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2019 |
Ascensión Pagán; Kate Nation Learning words via reading: Contextual diversity, spacing, and retrieval effects in adults Journal Article In: Cognitive Science, vol. 43, no. 1, pp. 1–24, 2019. @article{Pagan2019a, We examined whether variations in contextual diversity, spacing, and retrieval practice influenced how well adults learned new words from reading experience. Eye movements were recorded as adults read novel words embedded in sentences. In the learning phase, unfamiliar words were presented either in the same sentence repeated four times (same context) or in four different sentences (diverse context). Spacing was manipulated by presenting the sentences under distributed or non-distributed practice. After learning, half of the participants were asked to retrieve the new words, and half had an extra exposure to the new words. Although words experienced in diverse contexts were acquired more slowly during learning, they enjoyed a greater benefit of learning at immediate posttest. Distributed practice also slowed learning, but no benefit was observed at posttest. Although participants who had an extra exposure showed the greatest learning benefit overall, learning also benefited from retrieval opportunity, when words were experienced in diverse contexts. These findings demonstrate that variation in the content and structure of the learning environment impacts on word learning via reading. |
Joan López-Moliner; Cécile Vullings; Laurent Madelain; Robert J. Beers Prediction and final temporal errors are used for trial-to-trial motor corrections Journal Article In: Scientific Reports, vol. 9, pp. 19230, 2019. @article{LopezMoliner2019, Many daily life situations (e.g. dodging an approaching object or hitting a moving target) require people to correct planning of future movements based on previous temporal errors. However, the actual temporal error can be difficult to perceive: imagine a baseball batter that swings and misses a fastball. Here we show that in such situations people can use an internal error signal to make corrections in the next trial. This signal is based on the discrepancy between the actual and the planned action onset time: the prediction error. In this study, we used three interception tasks: reaching movements, saccadic eye movements and a button press that released a cursor moving ballistically for a fixed time. We found that action onset depended on the previous temporal error in the arm movement experiment only and not in the saccadic and button press experiments. However, this dependency was modulated by the movement time: faster arm movements depended less on the previous actual temporal error. An analysis using a Kalman filter confirmed that people used the prediction error rather than the previous temporal error for trial-by-trial corrections in fast arm movements, saccades and button press. |
Ya Lou; Huajian Cai; Xuewei Liu; Xingshan Li Effects of self-enhancement on eye movements during reading Journal Article In: Frontiers in Psychology, vol. 10, pp. 343, 2019. @article{Lou2019, Previous studies show that readers' eye movements are influenced by text properties and readers' personal cognitive characteristics. In the current study, we further show that readers' eye movements are influenced by a social motivation of self-enhancement. We asked participants to silently read sentences that describe self or others with positive or negative traits while their eyes were monitored. First-fixation duration and gaze duration were longer when positive words were used to describe self than to describe others, but there was no such effect for negative words. These results suggest that eye movements can be influenced by the motivation of self-enhancement in addition to various stimuli features and cognitive factors. This finding indicates that the eye movement methodology can potentially be used to study implicit social cognition. |
Kaleb A. Lowe; Thomas R. Reppert; Jeffrey D. Schall Selective influence and sequential operations: A research strategy for visual search Journal Article In: Visual Cognition, vol. 27, no. 5-8, pp. 387–415, 2019. @article{Lowe2019, We discuss the problem of elucidating mechanisms of visual search. We begin by considering the history, logic, and methods of relating behavioural or cognitive processes with neural processes. We then survey briefly the cognitive neurophysiology of visual search and essential aspects of the neural circuitry supporting this capacity. We introduce conceptually and empirically a powerful but underutilized experimental approach to dissect the cognitive processes supporting performance of a visual search task with factorial manipulations of singleton-distractor identifiability and stimulus-response cue discriminability. We show that systems factorial technology can distinguish processing architectures from the performance of macaque monkeys. This demonstration offers new opportunities to distinguish neural mechanisms through selective manipulation of visual encoding, search selection, rule encoding, and stimulus-response mapping. |
Jia E. Loy; Hannah Rohde; Martin Corley Real-time social reasoning: The effect of disfluency on the meaning of some Journal Article In: Journal of Cultural Cognitive Science, vol. 3, pp. 159–173, 2019. @article{Loy2019, The scalar quantifier some is locally ambiguous between pragmatic (some-but-not-all) and literal (some-and-possibly-all) meanings. Although comprehenders typically favour an eventual pragmatic interpretation, debate persists regarding what factors influence interpretation, the time course of comprehension, and whether literal meaning takes precedence. We investigate how the interpretation of some depends on social reasoning derived from a speaker's manner of delivery. Specifically, we test the effect of disfluency on the derivation of meaning in a context where hesitation may signal speaker embarrassment due to potential face-loss associated with the literal meaning of ‘‘some''. Participants ðn ¼ 24Þ viewed displays comprising two different snack quantities while hearing a recorded utterance describing how much a speaker had eaten. Critical utterances ðn ¼ 16Þ contained the quantifier some, half with a filled pause disfluency (‘‘I ate $backslash$uh[, some oreos''). Participants' eye and mouse movements showed (via empirical logit regressions) that fluent utterances yielded a bias toward a pragmatic interpretation, while disfluency attenuated this bias in favour of the literal meaning (where the speaker ate all the oreos). Crucially, this difference emerged rapidly post-onset of some. Taken together, our findings do not support a literal-first account of scalar comprehension, but rather, suggest that some is interpreted rapidly in a context-dependent manner. |
Anne-Claude Luisier; Annick Clerc Berod; Anne Raphäelle Richoz; Junpeng Lao; Roberto Caldara; Moustafa Bensafi Visual and hedonic perception of food stimuli in children with autism spectrum disorders and their relationship to food neophobia Journal Article In: Perception, vol. 48, no. 3, pp. 197–213, 2019. @article{Luisier2019, The present study examined whether children with autism spectrum disorder (ASD) and typically developing (TD) children differed in visual perception of food stimuli at both sensorimotor and affective levels. A potential link between visual perception and food neophobia was also investigated. To these aims, 11 children with ASD and 11 TD children were tested. Visual pictures of food were used, and food neophobia was assessed by the parents. Results revealed that children with ASD explored visually longer food stimuli than TD children. Complementary analyses revealed that whereas TD children explored more multiple-item dishes (vs. simple-item dishes), children with ASD explored all the dishes in a similar way. In addition, children with ASD gave more negative appreciation in general. Moreover, hedonic rating was negatively cor- related with food neophobia scores in children with ASD, but not in TD children. In sum, we show here that children with ASD have more difficulty than TD children in liking a food when presented visually. Our findings also suggest that a prominent factor that needs to be considered is time management during the food choice process. They also provide new ways of measuring and understanding food neophobia in children with ASD. |
Jiří Lukavský Scene categorization in the presence of a distractor Journal Article In: Journal of Vision, vol. 19, no. 2, pp. 1–11, 2019. @article{Lukavsky2019, Humans display a very good understanding of the content in briefly presented photographs. To achieve this understanding, humans rely on information from both high-acuity central vision and peripheral vision. Previous studies have investigated the relative contribution of central and peripheral vision. However, the role of attention in this task remains unclear. In this study, we presented composite images with a scene in the center and another scene in the periphery. The two channels conveyed different information, and the participants were asked to focus on one channel while ignoring the other. In two experiments, we showed that (a) people are better at recognizing the central part, (b) the conflicting signal in the ignored part hinders performance, and (c) this effect is true for both parts (focusing on the central or peripheral part).We conclude that scene recognition is based on both central and peripheral information, even when participants are instructed to focus only on one part of the image and ignore the other. In contrast to the zoom-out hypothesis, we propose that the gist recognition process should be interpreted in terms of the evidence accumulation model in which information from the to-be-ignored parts is also included. |
Junxiang Luo; Keyan He; Ian Max Andolina; Xiaohong Li; Jiapeng Yin; Zheyuan Chen; Yong Gu; Wei Wang Going with the flow: The neural mechanisms underlying illusions of complex-flow motion Journal Article In: Journal of Neuroscience, vol. 39, no. 14, pp. 2664 –2685, 2019. @article{Luo2019, Studying the mismatch between perception and reality helps us better understand the constructive nature of the visual brain. The Pinna-Brelstaff motion illusion is a compelling example illustrating how a complex moving pattern can generate an illusory motion perception. When an observer moves toward (expansion) or away (contraction) from the Pinna-Brelstaff figure, the figure appears to rotate. The neural mechanisms underlying the illusory complex-flow motion of rotation, expansion, and contraction remain unknown. We studied this question at both perceptual and neuronal levels in behaving male macaques by using carefully parametrized Pinna-Brelstaff figures that induce the above motion illusions. We first demonstrate that macaques perceive illusory motion in a manner similar to that of human observers. Neurophysiological recordings were subsequently performed in the middle temporal area (MT) and the dorsal portion of the medial superior temporal area (MSTd). We find that subgroups of MSTd neurons encoding a particular global pattern of real complex-flow motion (rotation, expansion, contraction) also represent illusory motion patterns of the same class. They require an extra 15 ms to reliably discriminate the illusion. In contrast, MT neurons encode both real and illusory local motions with similar temporal delays. These findings reveal that illusory complex-flow motion is first represented in MSTd by the same neurons that normally encode real complex-flow motion. However, the extraction of global illusory motion in MSTd from other classes of real complex-flow motion requires extra processing time. Our study illustrates a cascaded integration mechanism from MT to MSTd underlying the transformation from external physical to internal nonveridical flow-motion perception. |
Liya Ma; Jason L. Chan; Kevin D. Johnston; Stephen G. Lomber; Stefan Everling Macaque anterior cingulate cortex deactivation impairs performance and alters lateral prefrontal oscillatory activities in a rule-switching task Journal Article In: PLoS Biology, vol. 17, no. 7, pp. e3000045, 2019. @article{Ma2019b, In primates, both the dorsal anterior cingulate cortex (dACC) and the dorsolateral prefrontal cortex (dlPFC) are key regions of the frontoparietal cognitive control network. To study the role of the dACC and its communication with the dlPFC in cognitive control, we recorded local field potentials (LFPs) from the dlPFC before and during the reversible deactivation of the dACC, in macaque monkeys engaging in uncued switches between 2 stimulus-response rules, namely prosaccade and antisaccade. Cryogenic dACC deactivation impaired response accuracy during maintenance of—but not the initial switching to—the cognitively demanding antisaccade rule, which coincided with a reduction in task-related theta activity and the correct-error (C-E) difference in dlPFC beta-band power. During both rule switching and maintenance, dACC deactivation prolonged the animals' reaction time and reduced task-related alpha power in the dlPFC. Our findings support a role of the dACC in prefrontal oscillatory activities that are involved the maintenance of a new, challenging task rule. |
Mary H. MacLean; Tom Bullock; Barry Giesbrecht Dual process coding of recalled locations in human oscillatory brain activity Journal Article In: Journal of Neuroscience, vol. 39, no. 34, pp. 6737–6750, 2019. @article{MacLean2019, A mental representation of the location of an object can be constructed using sensory information selected from the environment and information stored internally. Human electrophysiological evidence indicates that behaviorally relevant locations, regardless of the source of sensory information, are represented in alpha-band oscillations suggesting a shared process. Here, we present evidence from human subjects of either sex for two distinct alpha-band-based processes that separately support the representation of location, exploiting sensory evidence sampled either externally or internally. |
Apoorva Rajiv Madipakkam; Gabriele Bellucci; Marcus Rothkirch; Soyoung Q. Park The influence of gaze direction on food preferences Journal Article In: Scientific Reports, vol. 9, pp. 5604, 2019. @article{Madipakkam2019, In our information-rich environment, the gaze direction of another indicates their current focus of attention. Following the gaze of another, results in gaze-evoked shifts in joint attention, a phenomenon critical for the functioning of social cognition. Previous research in joint attention has shown that objects that are attended by another are more liked than ignored objects. Here, we investigated this effect of gaze-cueing on participants' preferences for unknown food items. Participants provided their willingness to pay (WTP), taste and health preferences for food items before and after a standard gaze-cueing paradigm. We observed a significant effect of gaze-cueing on participants' WTP bids. Specifically, participants were willing to pay more money for the food items that were looked at by another person. In contrast, there was a decrease in preference for the food items that were ignored by another person. Interestingly, this increase in WTP occurred without participants' awareness of the contingency between the cue and target. These results highlight the influence of social information on human choice behavior and lay the foundation for experiments in neuromarketing and consumer decision making. |
2018 |
Melissa E. Milanak; Matt R. Judah; Howard Berenbaum; Arthur F. Kramer; Mark Neider PTSD symptoms and overt attention to contextualized emotional faces: Evidence from eye tracking Journal Article In: Psychiatry Research, vol. 269, pp. 408–413, 2018. @article{Milanak2018, Abnormal patterns of attention to emotional faces and images are proposed by theories of posttraumatic stress disorder (PTSD), and this has been demonstrated empirically. However, few studies have examined how PTSD symptoms are associated with attention to emotional faces in the context of emotional background images. Eye tracking data were collected from seventy-eight undergraduates with a history of experiencing at least one traumatic event as they completed the Contextual Recognition of Affective Faces Task (CRAFT; Milanak and Berenbaum, 2014), which requires subjects to identify the emotion depicted by faces superimposed on an emotional background image. Greater PTSD symptom severity was associated with more time spent looking at background contexts and less time looking at target faces. This is consistent with greater susceptibility to distraction by task-irrelevant emotional stimuli. The duration of each gaze fixation upon fear faces was shorter for those with greater PTSD symptoms, and this pattern was marginally significant for disgust faces. These findings suggest that PTSD symptoms may relate to greater attention toward non-facial background scenes and less attention toward facial stimuli, especially when conveying a fear or disgust expression. |
Ulrich Ettinger; Désirée S. Aichert; Nicola Wöstmann; Sandra Dehning; Michael Riedel; Veena Kumari Response inhibition and interference control: Effects of schizophrenia, genetic risk, and schizotypy Journal Article In: Journal of Neuropsychology, vol. 12, no. 3, pp. 484–510, 2018. @article{Ettinger2018a, The ability to inhibit inappropriate responses and suppress irrelevant information is a core feature of executive control. In this study, we provide a detailed analysis of prepotent response inhibition and interference in patients with schizophrenia. To further test the role of genetic factors and subclinical schizophrenia‐like traits, we additionally studied clinically unaffected, first‐degree relatives of schizophrenia patients and assessed dimensions of schizotypy in both relatives and healthy controls. Inhibition and interference control were assessed using a battery comprising the antisaccade, Stroop, stop signal, go/no‐go, flanker, and Simon tasks. Schizophrenia patients differed from both relatives and controls in making more errors on the antisaccade task and having longer response times on the Stroop task, especially the incongruent condition. Patients also had general, that is, condition independent, increases in reaction times on the go/no‐go and flanker tasks and made more errors on the flanker and Simon tasks, suggesting general performance impairments independent of inhibitory demand. Relatives were characterized by hypometric antisaccade amplitude gain despite normal prosaccades, suggesting a selective deficit in non‐standard sensorimotor transformations. Schizotypy was correlated with inhibitory performance across a number of tasks in both relatives and controls. Generally, these effects were independent of verbal intelligence levels. Overall, the findings point to rather selective impairments of inhibitory control in the schizophrenia spectrum and confirm a previously observed deficit in antisaccade spatial accuracy as an endophenotype of schizophrenia. |
Ricardo Kienitz; Joscha T. Schmiedt; Katharine A. Shapcott; Kleopatra Kouroupaki; Richard C. Saunders; Michael C. Schmid Theta rhythmic neuronal activity and reaction times arising from cortical receptive field interactions during distributed attention Journal Article In: Current Biology, vol. 28, no. 15, pp. 2377–2387, 2018. @article{Kienitz2018, Growing evidence suggests that distributed spatial attention may invoke theta (3–9 Hz) rhythmic sampling processes. The neuronal basis of such attentional sampling is, however, not fully understood. Here we show using array recordings in visual cortical area V4 of two awake macaques that presenting separate visual stimuli to the excitatory center and suppressive surround of neuronal receptive fields (RFs) elicits rhythmic multi-unit activity (MUA)at 3–6 Hz. This neuronal rhythm did not depend on small fixational eye movements. In the context of a distributed spatial attention task, during which the monkeys detected a spatially and temporally uncertain target, reaction times (RTs) exhibited similar rhythmic fluctuations. RTs were fast or slow depend-ing on the target occurrence during high or low MUA, resulting in rhythmic MUA-RT cross-correlations at theta frequencies. These findings show that theta rhythmic neuronal activity can arise from competitiveRF interactions and that this rhythm may result in rhythmic RTs potentially subserving attentional sampling. |
Candice C. Morey; Silvana Mareva; Jaroslaw R. Lelonkiewicz; Nicolas Chevalier Gaze-based rehearsal in children under 7: A developmental investigation of eye movements during a serial spatial memory task Journal Article In: Developmental Science, vol. 21, pp. 1–8, 2018. @article{Morey2018, The emergence of strategic verbal rehearsal at around 7 years of age is widely considered a major milestone in descriptions of the development of short‐term memory across childhood. Likewise, rehearsal is believed by many to be a crucial factor in explaining why memory improves with age. This apparent qualitative shift in mnemonic processes has also been characterized as a shift from passive visual to more active verbal mnemonic strategy use, but no investigation of the development of overt spatial rehearsal has informed this explanation. We measured serial spatial order reconstruction in adults and groups of children 5–7 years old and 8–11 years old, while recording their eye movements. Children, particularly the youngest children, overtly fixated late‐list spatial positions longer than adults, suggesting that younger children are less likely to engage in covert rehearsal during stimulus presentation than older children and adults. However, during retention the youngest children overtly fixated more of the to‐be‐remembered sequences than any other group, which is inconsistent with the idea that children do nothing to try to remember. Altogether, these data are inconsistent with the notion that children under 7 do not engage in any attempts to remember. They are most consistent with proposals that children's style of remembering shifts around age 7 from reactive cue‐driven methods to proactive, covert methods, which may include cumulative rehearsal. |
Kivilcim Afacan-Seref; Natalie A. Steinemann; Annabelle Blangero; Simon P. Kelly Dynamic interplay of value and sensory information in high-speed decision making Journal Article In: Current Biology, vol. 28, no. 5, pp. 795–802, 2018. @article{AfacanSeref2018, In dynamic environments, split-second sensorimotor decisions must be prioritized according to potential payoffs to maximize overall rewards. The impact of relative value on deliberative perceptual judgments has been examined extensively [1–6], but relatively little is known about value-biasing mechanisms in the common situation where physical evidence is strong but the time to act is severely limited. In prominent decision models, a noisy but statistically stationary representation of sensory evidence is integrated over time to an action-triggering bound, and value-biases are affected by starting the integrator closer to the more valuable bound. Here, we show significant departures from this account for humans making rapid sensory-instructed action choices. Behavior was best explained by a simple model in which the evidence representation—and hence, rate of accumulation—is itself biased by value and is non-stationary, increasing over the short decision time frame. Because the value bias initially dominates, the model uniquely predicts a dynamic ‘‘turn-around'' effect on low-value cues, where the accumulator first launches toward the incorrect action but is then re-routed to the correct one. This was clearly exhibited in electrophysiological signals reflecting motor preparation and evidence accumulation. Finally, we construct an extended model that implements this dynamic effect through plausible sensory neural response modulations and demonstrate the correspondence between decision signal dynamics simulated from a behavioral fit of that model and the empirical decision signals. Our findings suggest that value and sensory information can exert simultaneous and dynamically countervailing influences on the trajectory of the accumulation-to-bound process, driving rapid, sensory-guided actions. |
Nicolas Chevalier; Bruno Dauvier; Agnès Blaye From prioritizing objects to prioritizing cues: A developmental shift for cognitive control Journal Article In: Developmental Science, vol. 21, no. 2, pp. 1–8, 2018. @article{Chevalier2018, Emerging cognitive control supports increasingly adaptive behaviors and predicts life success, while low cognitive control is a major risk factor during childhood. It is therefore essential to understand how it develops. The present study provides evidence for an age‐related shift in the type of information that children prioritize in their environment, from objects that can be directly acted upon to cues signaling how to act. Specifically, gaze patterns recorded while 3‐ to 12‐year‐olds and adults engaged in a cognitive control task showed that whereas younger children fixated on targets that they needed to respond to before gazing at task cues signaling how to respond, older children and adults showed the opposite pattern (which yielded better performance). This shift in information prioritization has important conceptual implications, suggesting that a major force behind cognitive control development may be non‐executive in nature, as well as opening new directions for interventions. |
Wendy Troop-Gordon; Robert D. Gordon; Bethany M. Schwandt; Gregor A. Horvath; Elizabeth Ewing Lee; Kari J. Visconti Allocation of attention to scenes of peer harassment: Visual–cognitive moderators of the link between peer victimization and aggression Journal Article In: Development and Psychopathology, pp. 1–16, 2018. @article{TroopGordon2018, As approximately one-third of peer-victimized children evidence heightened aggression (Schwartz, Proctor, & Chien, 2001), it is imperative to identify the circumstances under which victimization and aggression co-develop. The current study explored two potential moderators of victimization–aggression linkages: (a) attentional bias toward cues signaling threat and (b) attentional bias toward cues communicating interpersonal support. Seventy-two fifth- and sixth-grade children (34 boys = 11.67) were eye tracked while watching video clips of bullying. Each scene included a bully, a victim, a reinforcer, and a defender. Children's victimization was measured using peer, parent, and teacher reports. Aggression was measured using peer reports of overt and relational aggression and teacher reports of aggression. Victimization was associated with greater aggression at high levels of attention to the bully. Victimization was also associated with greater aggression at low attention to the defender for boys, but at high attention to the defender for girls. Attention to the victim was negatively correlated with aggression regardless of victimization history. Thus, attentional biases to social cues integral to the bullying context differentiate whether victimization is linked to aggression, necessitating future research on the development of these biases and concurrent trajectories of sociobehavioral development. |
Joshua D. Cosman; Kaleb A. Lowe; Wolf Zinke; Geoffrey F. Woodman; Jeffrey D. Schall Prefrontal control of visual distraction Journal Article In: Current Biology, vol. 28, no. 3, pp. 414–420, 2018. @article{Cosman2018, Avoiding distraction by conspicuous but irrelevant stimuli is critical to accomplishing daily tasks. Regions of prefrontal cortex control attention by enhancing the representation of task-relevant information in sensory cortex, which can be measured in modulation of both single neurons and event-related electrical potentials (ERPs) on the cranial surface [1, 2]. When irrelevant information is particularly conspicuous, it can distract attention and interfere with the selection of behaviorally relevant information. Such distraction can be minimized via top-down control [3–5], but the cognitive and neural mechanisms giving rise to this control over distraction remain uncertain and debated [6–9]. Bridging neurophysiology to electrophysiology, we simultaneously recorded neurons in prefrontal cortex and ERPs over extrastriate visual cortex to track the processing of salient distractors during a visual search task. Critically, when the salient distractor was successfully ignored, but not otherwise, we observed robust suppression of salient distractor representations. Like target selection, the distractor suppression was observed in prefrontal cortex before it appeared over extrastriate cortical areas. Furthermore, all prefrontal neurons that showed suppression of the task-irrelevant distractor also contributed to selecting the target. This suggests a common prefrontal mechanism is responsible for both selecting task-relevant and suppressing task-irrelevant information in sensory cortex. Taken together, our results resolve a long-standing debate over the mechanisms that prevent distraction, and provide the first evidence directly linking suppressed neural firing in prefrontal cortex with surface ERP measures of distractor suppression. |
Leanne Chukoskie; Marissa Westerfield; Jeanne Townsend A novel approach to training attention and gaze in ASD: A feasibility and efficacy pilot study Journal Article In: Developmental Neurobiology, vol. 78, no. 5, pp. 546–554, 2018. @article{Chukoskie2018, In addition to the social, communicative and behavioral symptoms that define the disorder, individuals with ASD have difficulty reorienting attention quickly and accurately. Similarly, fast reorienting saccadic eye movements are also inaccurate and more variable in both endpoint and timing. Atypical gaze and attention are among the earliest symptoms observed in ASD. Disruption of these foundation skills critically affects the development of higher level cognitive and social behavior. We propose that interventions aimed at these early deficits that support social and cognitive skills will be broadly effective. We conducted a pilot clinical trial designed to demonstrate the feasibility and preliminary efficacy of using gaze-contingent video games for low-cost in-home training of attention and eye movement. Eight adolescents with ASD participated in an 8-week training, with pre-, mid-and post-testing of eye movement and attention control. Six of the eight adolescents completed the 8 weeks of training and all six showed improvement in attention (orienting, disengagement) and eye movement control or both. All game systems remained intact for the duration of training and all participants could use the system independently. We delivered a robust, low-cost, gaze-contingent game system for home use that, in our pilot training sample, improved the attention orienting and eye movement performance of adolescent participants in 8 weeks of training. We are currently conducting a clinical trial to replicate these results and to examine what, if any, aspects of training transfer to more real-world tasks. |
Rosie Clark; Iain D. Gilchrist The relationship between reward and probability: Evidence that exploration may be intrinsically rewarding Journal Article In: Visual Cognition, vol. 26, no. 9, pp. 672–694, 2018. @article{Clark2018, The probability of an event occurring and the reward associated with the event can both modulate behaviour. Response times are decreased to stimuli that are either more rewarding or more likely. These two factors can be combined to give an Expected Value (EV) associated with the event (i.e., probability of the event x reward magnitude). In four experiments we investigate the effect of reward and probability on both saccadic and manual responses. When tested separately we find evidence for both a reward and probability effect across response types. When manipulations of reward magnitude and probability of the event were combined, the probability modulations dominated and these data were not well accounted for by the EV. However, a post-hoc model that included an additional intrinsic reward associated with responding provided an excellent account for the data. We argue that reward consists of both an explicit and intrinsic component. In our task, the saccadic and manual responses are linked to the information provided by the targets and the goals of the task, and successful completion of these is in itself rewarding. As a result, targets associated with a higher probability of being presented have a higher intrinsic reward. |
Meaghan Clough; Steven Mutimer; David K. Wright; Adrian Tsang; Daniel M. Costello; Andrew J. Gardner; Peter Stanwell; Richelle Mychasiuk; Mujun Sun; Rhys D. Brady; Stuart J. McDonald; Kyria M. Webster; Maddison R. Johnstone; Bridgette D. Semple; Denes V. Agoston; Owen B. White; Richard Frayne; Joanne Fielding; Terence J. O'Brien; Sandy R. Shultz Oculomotor cognitive control abnormalities in Australian rules football players with a history of concussion Journal Article In: Journal of Neurotrauma, vol. 35, no. 5, pp. 730–738, 2018. @article{Clough2018, This study used oculomotor, cognitive, and multi-modal magnetic resonance imaging (MRI) measures to assess for neurological abnormalities in current asymptomatic amateur Australian rules footballers (i.e., Australia's most participated collision sport) with a history of sports-related concussion (SRC). Participants were 15 male amateur Australian rules football players with a history of SRC greater than 6 months previously, and 15 sex-, age-, and education-matched athlete control subjects that had no history of neurotrauma or participation in collision sports. Participants completed a clinical interview, neuropsychological measures, and oculomotor measures of cognitive control. MRI investigation involved structural imaging, as well as diffusion tensor imaging and resting-state functional MRI sequences. Despite no group differences on conventional neuropsychological tests and multi-modal MRI measures, Australian rules football players with a history of SRC performed significantly worse on an oculomotor switch task: a measure of cognitive control that interleaves the response of looking towards a target (i.e., a prosaccade) with the response of looking away from a target (i.e., an antisaccade). Specifically, Australian footballers performed significantly shorter latency prosaccades and found changing from an antisaccade trial to a prosaccade trial (switch cost) significantly more difficult than control subjects. Poorer switch cost was related to poorer performance on a number of neuropsychological measures of inhibitory control. Further, when comparing performance on the cognitively more demanding switch task with performance on simpler, antisaccade/prosaccades tasks which require a single response, Australian footballers demonstrated a susceptibility to increased cognitive load, compared to the control group who were unaffected. These initial results suggest that current asymptomatic amateur Australian rules football players with a history of SRC may have persisting, subtle, cognitive changes, which are demonstrable on oculomotor cognitive measures. Future studies are required in order to further elucidate the full nature and clinical relevance of these findings. |
Moreno I. Coco; Rick Dale; Frank Keller Performance in a collaborative search task: The role of feedback and alignment Journal Article In: Topics in Cognitive Science, vol. 10, no. 1, pp. 55–79, 2018. @article{Coco2018, When people communicate, they coordinate a wide range of linguistic and non-linguistic behaviors. This process of coordination is called alignment, and it is assumed to be fundamental to successful communication. In this paper, we question this assumption and investigate whether disalignment is a more successful strategy in some cases. More specifically, we hypothesize that alignment correlates with task success only when communication is interactive. We present results from a spot-the-difference task in which dyads of interlocutors have to decide whether they are viewing the same scene or not. Interactivity was manipulated in three conditions by increasing the amount of information shared between interlocutors (no exchange of feedback, minimal feedback, full dialogue). We use recurrence quantification analysis to measure the alignment between the scan-patterns of the interlocutors. We found that interlocutors who could not exchange feedback aligned their gaze more, and that increased gaze alignment correlated with decreased task success in this case. When feedback was possible, in contrast, interlocutors utilized it to better organize their joint search strategy by diversifying visual attention. This is evidenced by reduced over-all alignment in the minimal feedback and full dialogue conditions. However, only the dyads engaged in a full dialogue increased their gaze alignment over time to achieve successful performances. These results suggest that alignment per se does not imply communicative success, as most models of dialogue assume. Rather, the effect of alignment depends on the type of alignment, on the goals of the task, and on the presence of feedback. |
Carlotta Cogoni; Andrea Carnaghi; Aleksandra Mitrovic; Helmut Leder; Carlo Fantoni; Giorgia Silani Understanding the mechanisms behind the sexualized-body inversion hypothesis: The role of asymmetry and attention biases Journal Article In: PLoS ONE, vol. 13, no. 4, pp. e0193944, 2018. @article{Cogoni2018, A controversial hypothesis, named the Sexualized Body Inversion Hypothesis (SBIH), claims similar visual processing of sexually objectified women (i.e., with a focus on the sexual body parts) and inanimate objects as indicated by an absence of the inversion effect for both type of stimuli. The current study aims at shedding light into the mechanisms behind the SBIH in a series of 4 experiments. Using a modified version of Bernard et al.'s (2012) visual-matching task, first we tested the core assumption of the SBIH, namely that a similar processing style occurs for sexualized human bodies and objects. In Experiments 1 and 2 a non-sexualized (personalized) condition plus two object-control conditions (mannequins, and houses) were included in the experimental design. Results showed an inversion effect for images of personalized women and mannequins, but not for sexualized women and houses. Second, we explored whether this effect was driven by differences in stimulus asymmetry, by testing the mediating and moderating role of this visual feature. In Experiment 3, we provided the first evidence that not only the sexual attributes of the images but also additional perceptual features of the stimuli, such as their asymmetry, played a moderating role in shaping the inversion effect. Lastly, we investigated the strategy adopted in the visual-matching task by tracking eye movements of the participants. Results of Experiment 4 suggest an association between a specific pattern of visual exploration of the images and the presence of the inversion effect. Findings are discussed with respect to the literature on sexual objectification. |
Haggar Cohen-Dallal; Isaac Fradkin; Yoni Pertzov Are stronger memories forgotten more slowly? No evidence that memory strength influences the rate of forgetting Journal Article In: PLoS ONE, vol. 13, no. 7, pp. e0200292, 2018. @article{CohenDallal2018, Information stored in visual short-term memory is used ubiquitously in daily life; however, it is forgotten rapidly within seconds. When more items are to be remembered, they are forgotten faster, potentially suggesting that stronger memories are forgotten less rapidly. Here we tested this prediction with three experiments that assessed the influence of memory strength on the rate of forgetting of visual information without manipulating the number of items. Forgetting rate was assessed by comparing the accuracy of reports in a delayed-estimation task following relatively short and long retention intervals. In the first experiment, we compared the forgetting rate of items that were directly fixated, to items that were not. In Experiments 2 and 3 we manipulated memory strength by extending the exposure time of one item in the memory array. As expected, direct fixation and longer exposure led to better accuracy of reports, reflecting stronger memory. However, in all three experiments, we did not find evidence that increased memory strength moderated the forgetting rate. |
Olympia Colizoli; Jan Willem Gee; Anne E. Urai; Tobias H. Donner Task-evoked pupil responses reflect internal belief states Journal Article In: Scientific Reports, vol. 8, pp. 13702, 2018. @article{Colizoli2018, Perceptual decisions about the state of the environment are often made in the face of uncertain evidence. Internal uncertainty signals are considered important regulators of learning and decision-making. A growing body of work has implicated the brain's arousal systems in uncertainty signaling. Here, we found that two specific computational variables, postulated by recent theoretical work, evoke boosts of arousal at different times during a perceptual decision: decision confidence (the observer's internally estimated probability that a choice was correct given the evidence) before feedback, and prediction errors (deviations from expected reward) after feedback. We monitored pupil diameter, a peripheral marker of central arousal state, while subjects performed a challenging perceptual choice task with a delayed monetary reward. We quantified evoked pupil responses during decision formation and after reward-linked feedback. During both intervals, decision difficulty and accuracy had interacting effects on pupil responses. Pupil responses negatively scaled with decision confidence prior to feedback and scaled with uncertainty-dependent prediction errors after feedback. This pattern of pupil responses during both intervals was in line with a model using the observer's graded belief about choice accuracy to anticipate rewards and compute prediction errors. We conclude that pupil-linked arousal systems are modulated by internal belief states. |
Jason C. Coronel; Matthew D. Sweitzer Remembering political messages in dynamic information environments: Insights from eye movements Journal Article In: Human Communication Research, vol. 44, no. 4, pp. 374–398, 2018. @article{Coronel2018, An important but understudied characteristic of the information environment involves political information changing across time. This dynamic feature of the environment can make it difficult for voters to possess accurate political knowledge. In this study, we assessed memory for political information using self-report and eye movement methods. We used these metrics to examine how individuals learn facts about policies whose important features have changed across time. We find that eye movements can accurately assess changes in political information even when self-reports fail to do so. Our results highlight the utility of a converging methods approach in the study of dynamic information environments, and specify mechanisms that facilitate or inhibit people's capacity to recognize changes in political information. |
Antoine Coutrot; Janet H. Hsiao; Antoni B. Chan Scanpath modeling and classification with hidden Markov models Journal Article In: Behavior Research Methods, vol. 50, pp. 362–379, 2018. @article{Coutrot2018, How people look at visual information reveals fundamental information about them; their interests and their states of mind. Previous studies showed that scanpath, i.e., the sequence of eye movements made by an observer exploring a visual stimulus, can be used to infer observer- related (e.g., task at hand) and stimuli-related (e.g., image semantic category) information. However, eye movements are complex signals and many of these studies rely on lim- ited gaze descriptors and bespoke datasets. Here, we provide a turnkey method for scanpath modeling and classification. This method relies on variational hidden Markov models (HMMs) and discriminant analysis (DA). HMMs encap- sulate the dynamic and individualistic dimensions of gaze behavior, allowing DA to capture systematic patterns diag- nostic of a given class of observers and/or stimuli. We test our approach on two very different datasets. Firstly, we use fixations recorded while viewing 800 static natural scene images, and infer an observer-related characteristic: the task at hand. We achieve an average of 55.9% correct classification rate (chance = 33%). We show that correct classification rates positively correlate with the number of salient regions present in the stimuli. Secondly, we use eye positions recorded while viewing 15 conversational videos, and infer a stimulus-related characteristic: the presence or absence of original soundtrack. We achieve an average 81.2% correct classification rate (chance = 50%). HMMs allow to integrate bottom-up, top-down, and oculomotor influences into a single model of gaze behavior. This syn- ergistic approach between behavior and machine learning will open new avenues for simple quantification of gazing behavior. We release SMAC with HMM, a Matlab toolbox freely available to the community under an open-source license agreement. |
Cynthia Y. H. Chan; Antoni B. Chan; Tatia M. C. Lee; Janet H. Hsiao Eye-movement patterns in face recognition are associated with cognitive decline in older adults Journal Article In: Psychonomic Bulletin & Review, vol. 25, no. 6, pp. 2200–2207, 2018. @article{Chan2018, The Hidden Markov Modeling approach for eye-movement data analysis is able to quantitatively assess differences and similarities among individual patterns. Here we applied this approach to examine the relationships between eye-movement patterns in face recognition and age-related cognitive decline. We found that significantly more older than young adults adopted "holistic" patterns, in which most eye fixations landed around the face center, as opposed to "analytic" patterns, in which eye movements switched among the two eyes and the face center. Participants showing analytic patterns had better performance than those with holistic patterns regardless ofage. Interestingly, older adults with lower cognitive status (as assessed by the Montreal Cognitive Assessment), particularly in executive and visual attention functioning (as assessed by Tower of London and Trail Making Tests) were associated with a higher likelihood of holistic patterns. This result suggests the possibility of using eye movements as an easily deployable screening assessment for cognitive decline in older adults. |
Chun-Ting Chen; Chen-Ying Huang; Joseph Tao-yi Wang A window of cognition: Eyetracking the reasoning process in spatial beauty contest games Journal Article In: Games and Economic Behavior, vol. 111, pp. 143–158, 2018. @article{Chen2018b, We study the reasoning process in an environment where final choices are well understood and the associated theory is procedural by introducing two-person beauty contest games played spatially on two-dimensional grid maps. Players choose locations and are rewarded by hitting targets dependent on opponents' choice locations. By tracking subjects' eye movements (lookups), we infer their reasoning process and classify subjects into various levels. More than a half of the subjects' classifications coincides with their classifications using final choices, supporting a literal interpretation of the level-k model for subject's reasoning process. Lookup analyses reveal that the center area is where most subjects initially look at. This sheds light on the level-0 belief. Moreover, learning lookups of a trial on average could increase payoffs of that trial and eliminates roughly 60% of the gap to empirical best response, indicating how valuable lookups can help predict choices. |
Dinah Chen; Jorge Otero-Millan; Priyanka Kumar; Aasef G. Shaikh; Fatema F. Ghasia Visual search in amblyopia: Abnormal fixational eye movements and suboptimal sampling strategies Journal Article In: Investigative Ophthalmology & Visual Science, vol. 59, no. 11, pp. 4506–4517, 2018. @article{Chen2018a, Purpose: Microsaccades shift the image on the fovea and counteract visual fading. They are also thought to serve as an optimal sampling strategy while viewing complex visual scenes. The goal of our study was to assess visual search in amblyopic children. Methods: Twenty-one amblyopic children with varying severity of amblyopia and 10 healthy controls were recruited. Eye movements were recorded using infrared video-oculography during amblyopic and fellow eye viewing while the subjects performed (1) visual fixation, (2) exploration of a blank scene, and (3) visual search task (spot the difference between two images). The number of correctly identified picture differences and reaction time were recorded. Microsaccade, saccades, and intersaccadic drifts were analyzed in patients without latent nystagmus (LN). Slow phase velocities were computed for patients with LN. Results: Both patients with and without LN were able to spot the same number of differences but took longer during fellow eye viewing compared to controls. The ability to identify differences was diminished during amblyopic eye viewing particularly those with LN and severe amblyopia. We found reduced frequencies of microsaccades and saccades in both amblyopic and fellow eyes during fixation and visual search but not during exploration of blank scene. Across all tasks, amblyopes with LN had increased intersaccadic drifts. Conclusions: Our findings suggest that deficient microsaccade and saccadic activity contributes to poorer sampling strategy in amblyopia, which is seen in both amblyopic and fellow eye. These deficits are more notable among subjects who experienced binocular decorrelation earlier in life, with subsequent development of LN. |
Xuqian Chen; Wei Yang; Lijun Ma; Jiaxin Li In: Frontiers in Psychology, vol. 9, pp. 211, 2018. @article{Chen2018, Recent findings have shown that information about changes in an object's environmental location in the context of discourse is stored in working memory during sentence comprehension. However, in these studies, changes in the object's location were always consistent with world knowledge (e.g., in “The writer picked up the pen from the floor and moved it to the desk,” the floor and the desk are both common locations for a pen). How do people accomplish comprehension when the object-location information in working memory is inconsistent with world knowledge (e.g., a pen being moved from the floor to the bathtub)? In two visual world experiments, with a “look-and-listen” task, we used eye-tracking data to investigate comprehension of sentences that described location changes under different conditions of appropriateness (i.e., the object and its location were typically vs. unusually coexistent, based on world knowledge) and antecedent context (i.e., contextual information that did vs. did not temporarily normalize unusual coexistence between object and location). Results showed that listeners' retrieval of the critical location was affected by both world knowledge and working memory, and the effect of world knowledge was reducedwhen the antecedent context normalized unusual coexistence of object and location. More importantly, activation of world knowledge and working memory seemed to change during the comprehension process. These results are important because they demonstrate that interference between world knowledge and information in working memory, appears to be activated dynamically during sentence comprehension. |
Mariya V. Cherkasova; Luke Clark; Jason J. S. Barton; Michael Schulzer; Mahsa Shafiee; Alan Kingstone; A. Jon Stoessl; Catharine A. Winstanley Win-concurrent sensory cues can promote riskier choice Journal Article In: Journal of Neuroscience, vol. 38, no. 48, pp. 10362–10370, 2018. @article{Cherkasova2018, Reward-related stimuli can potently influence behavior; for example, exposure to drug-paired cues can trigger drug use and relapse in people with addictions. Psychological mechanisms that generate such outcomes likely include cue-induced cravings and attentional biases. Recent animal data suggest another candidate mechanism: reward-paired cues can enhance risky decision making, yet whether this translates to humans is unknown. Here, we examined whether sensory reward-paired cues alter decision making under uncertainty and risk, as measured respectively by the Iowa Gambling Task and a two-choice lottery task. In the cued versions of both tasks, gain feedback was augmented with reward-concurrent audiovisual stimuli. Healthy human volunteers (53 males, 78 females) performed each task once, one with and the other without cues (cued Iowa Gambling Task/uncued Vancouver Gambling Task: n = 63; uncued Iowa Gambling Task/cued Vancouver Gambling Task: n = 68), with concurrent eye-tracking. Reward-paired cues did not affect choice on the Iowa Gambling Task. On the two-choice lottery task, the cued group displayed riskier choice and reduced sensitivity to probability information. The cued condition was associated with reduced eye fixations on probability information shown on the screen and greater pupil dilation related to decision and reward anticipation. This pupil effect was unrelated to the risk-promoting effects of cues: the degree of pupil dilation for risky versus risk-averse choices did not differ as a function of cues. Together, our data show that sensory reward cues can promote riskier decisions and have additional and distinct effects on arousal. |
Gregory J. Christie; Thomas M. Spalek; John J. McDonald Salience drives overt selection of two equally relevant visual targets Journal Article In: Attention, Perception, and Psychophysics, vol. 80, no. 6, pp. 1342–1349, 2018. @article{Christie2018, In the present study, we investigated whether salience determines the sequence of selection when participants search for two equally relevant visual targets. To do this, attentional selection was tracked overtly as observers inspected two items of differing physical salience: one a highly salient color singleton, and the other a less salient shape singleton. Participants were instructed to make natural eye movements in order to determine whether two line segments contained within the two singletons were oriented in the same or in different directions. Because both singleton items were task-relevant, participants had no reason to inspect one item before the other. As expected, observers fixated both targets on the majority of trials. Critically, saccades to the color singleton preceded saccades to the less salient shape singleton on the majority of trials. This demonstrates that the order of attentional object selection is largely determined by stimulus salience when task relevance is equated. |
Philippe Bernard; Sarah J. Gervais; Arianne M. Holland; Michael D. Dodd When do people "check out" male bodies? Appearance-focus increases the objectifying gaze toward men Journal Article In: Psychology of Men & Masculinity, vol. 19, no. 3, pp. 484–489, 2018. @article{Bernard2018, Objectification studies have mostly focused on why and how women are objectified, but relatively little is known about what drives the objectification of men. This article aims to examine the objectifying gaze toward men, which is operationalized in the present article as decreased focus on men's faces and increased focus on men's body parts (arms, chest, and stomach). We considered the role of appearance (vs. personality) focus and ideal body shape on the objectifying gaze toward men. Specifically, we instructed 65 participants (36 men) to either evaluate the appearance or the personality of men while their eyes were monitored. To assess the objectifying gaze, we examined dwell time (i.e., total time spent fixating on an area) on targets' face, arms, chest, and stomach as well as first fixation time (i.e., how quickly face, arms, and stomach were fixated relative to the onset of the image). Consistent with our main hypothesis, results indicated that appearance-focused participants looked at faces for less time and chests, arms, and stomachs for more time than personality-focused participants. Participants also looked at men's arms for more time for men's bodies with high (vs. average and low) ideal body shapes. We discus these results and their implications in the light of objectification and body perception theories. |
Jutta Billino; Goedele Belle; Bruno Rossion; Gudrun Schwarzer The nature of individual face recognition in preschool children: Insights from a gaze-contingent paradigm Journal Article In: Cognitive Development, vol. 47, pp. 168–180, 2018. @article{Billino2018, The development of individual face recognition has been intensively studied and supports early expertise in childhood. However, how the differential use of holistic and analytical face processing modes contribute to the well-documented prolonged development of individual face recognition until adulthood remains poorly understood. We applied a gaze-contingency approach to study individual face recognition in 5-year-old children and young adults, allowing selective manipulation of processing modes and providing insights into facial information use through fixation patterns. Although both age groups relied on similar processing modes, children were less efficient in compensating for processing manipulations, in particular when analytical processing was emphasized. They were also less flexible in using facial information. Our findings suggest that efficiency in adaptively exploiting visual information contributes to still developing individual face recognition abilities in children. |
Daniel K. Bjornn; Bonnie Brinton Anderson; Anthony Vance; Jeffrey L. Jenkins; C. Brock Kirwan Tuning out security warnings: A longitudinal examination of habituation through fMRI, eye tracking, and field experiments Journal Article In: MIS Quarterly, vol. 42, no. 2, pp. 355–380, 2018. @article{Bjornn2018, Research in the fields of information systems and human-computer interaction has shown that habituation— decreased response to repeated stimulation—is a serious threat to the effectiveness of security warnings. Although habituation is a neurobiological phenomenon that develops over time, past studies have only examined this problem cross-sectionally. Further, past studies have not examined how habituation influences actual security warning adherence in the field. For these reasons, the full extent of the problem of habituation is unknown. We address these gaps by conducting two complementary longitudinal experiments. First, we performed an experiment collecting fMRI and eye-tracking data simultaneously to directly measure habituation to security warnings as it develops in the brain over a five-day workweek. Our results show not only a general decline of participants' attention to warnings over time but also that attention recovers at least partially between workdays without exposure to the warnings. Further, we found that updating the appearance of a warning— that is, a polymorphic design—substantially reduced habituation of attention. Second, we performed a three-week field experiment in which users were naturally exposed to privacy permis-sion warnings as they installed apps on their mobile devices. Consistent with our fMRI results, users' warning adherence substantially decreased over the three weeks. However, for users who received polymorphic permis-sion warnings, adherence dropped at a substantially lower rate and remained high after three weeks, compared to users who received standard warnings. Together, these findings provide the most complete view yet of the problem of habituation to security warnings and demonstrate that polymorphic warnings can substantially improve adherence. |
Nicholas S. Bland; Jason B. Mattingley; Martin V. Sale No evidence for phase-specific effects of 40 Hz HD-tACS on multiple object tracking Journal Article In: Frontiers in Psychology, vol. 9, pp. 304, 2018. @article{Bland2018, Phase synchronisation drives connectivity between neural oscillators, providing a flexible mechanism through which information can be effectively and selectively routed between task-relevant cortical areas. The ability to keep track of objects moving between the left and right visual hemifields, for example, requires the integration of information between the two cerebral hemispheres. Both animal and human studies have suggested that coherent (or phase-locked) gamma oscillations (30–80 Hz) might underlie this ability. While most human evidence has been strictly correlational, high-density transcranial alternating current stimulation (HD-tACS) has been used to manipulate ongoing interhemispheric gamma phase relationships. Previous research showed that 40 Hz tACS delivered bilaterally over human motion complex could bias the perception of a bistable ambiguous motion stimulus (Helfrich et al., 2014). Specifically, this work showed that in-phase (0° offset) stimulation boosted endogenous interhemispheric gamma coherence and biased perception toward the horizontal (whereby visual tokens moved between visual hemifields—requiring interhemispheric integration). By contrast, anti-phase (180° offset) stimulation decreased interhemispheric gamma coherence and biased perception toward the vertical (whereby tokens moved within separate visual hemifields). Here we devised a multiple object tracking arena comprised of four quadrants whereby discrete objects moved either entirely within the left and right visual hemifields, or could cross freely between visual hemifields, thus requiring interhemispheric integration. Using the same HD-tACS montages as Helfrich et al. (2014), we found no phase-specific effect of 40 Hz stimulation on overall tracking performance. While tracking performance was generally lower during between-hemifield trials (presumably reflecting a cost of integration), this difference was unchanged by in- versus anti-phase stimulation. Our null results could be due to a failure to reliably modulate coherence in our study, or that our task does not rely as heavily on this network of coherent gamma oscillations as other visual integration paradigms. |
Johannes Bloechle; Stefan Huber; Elise Klein; Julia Bahnmueller; Johannes Rennig; Korbinian Moeller; Julia F. Huber Spatial arrangement and set size influence the coding of non-symbolic quantities in the intraparietal sulcus Journal Article In: Frontiers in Human Neuroscience, vol. 12, pp. 54, 2018. @article{Bloechle2018a, Performance in visual quantification tasks shows two characteristic patterns as a function of set size. A precise subitizing process for small sets (up to four) was contrasted with an approximate estimation process for larger sets. The spatial arrangement of elements in a set also influences visual quantification performance, with frequently perceived arrangements (e.g., dice patterns) being faster enumerated than random arrangements. Neuropsychological and imaging studies identified the intraparietal sulcus (IPS), as key brain area for quantification, both within and above the subitizing range. However, it is not yet clear if and how set size and spatial arrangement of elements in a set modulate IPS activity during quantification. In an fMRI study, participants enumerated briefly presented dot patterns with random, canonical or dice arrangement within and above the subitizing range. We evaluated how activity amplitude and pattern in the IPS were influenced by size and spatial arrangement of a set. We found a discontinuity in the amplitude of IPS response between subitizing and estimation range, with steep activity increase for sets exceeding four elements. In the estimation range, random dot arrangements elicited stronger IPS response than canonical arrangements which in turn elicited stronger response than dice arrangements. Furthermore, IPS activity patterns differed systematically between arrangements. We found a signature in the IPS response for a transition between subitizing and estimation processes during quantification. Differences in amplitude and pattern of IPS activity for different spatial arrangements indicated a more precise representation of non-symbolic numerical magnitude for dice and canonical than for random arrangements. These findings challenge the idea of an abstract coding of numerosity in the IPS even within a single notation. |
Sage E. P. Boettcher; Dejan Draschkow; Eric Dienhart; Melissa L. -H. Võ Anchoring visual search in scenes: Assessing the role of anchor objects on eye movements during visual search Journal Article In: Journal of Vision, vol. 18, no. 13, pp. 1–13, 2018. @article{Boettcher2018, The arrangement of the contents of real-world scenes follows certain spatial rules that allow for extremely efficient visual exploration. What remains underexplored is the role different types of objects hold in a scene. In the current work, we seek to unveil an important building block of scenes—anchor objects. Anchors hold specific spatial predictions regarding the likely position of other objects in an environment. In a series of three eye tracking experiments we tested what role anchor objects occupy during visual search. In all of the experiments, participants searched through scenes for an object that was cued in the beginning of each trial. Critically, in half of the scenes a target relevant anchor was swapped for an irrelevant, albeit semantically consistent, object. We found that relevant anchor objects can guide visual search leading to faster reaction times, less scene coverage, and less time between fixating the anchor and the target. The choice of anchor objects was confirmed through an independent large image database, which allowed us to identify key attributes of anchors. Anchor objects seem to play a unique role in the spatial layout of scenes and need to be considered for understanding the efficiency of visual search in realistic stimuli. |
Anil Bollimunta; Amarender R. Bogadhi; Richard J. Krauzlis Comparing frontal eye field and superior colliculus contributions to covert spatial attention Journal Article In: Nature Communications, vol. 9, pp. 3553, 2018. @article{Bollimunta2018, The causal roles of the frontal eye fields (FEF) and superior colliculus (SC) in spatial selective attention have not been directly compared. Reversible inactivation is an established method for testing causality but comparing results between FEF and SC is complicated by differences in size and morphology of the two brain regions. Here we exploited the fact that inactivation of FEF and SC also changes the metrics of saccadic eye movements, providing an independent benchmark for the strength of the causal manipulation. Using monkeys trained to covertly perform a visual motion-change detection task, we found that inactivation of either FEF or SC could cause deficits in attention task performance. However, SC-induced attention deficits were found with saccade changes half the size needed to get FEF-induced attention deficits. Thus, performance in visual attention tasks is vulnerable to loss of signals from either structure, but suppression of SC activity has a more devastating effect. |
Michael B. Bone; Marie St-Laurent; Christa Dang; Douglas A. McQuiggan; Jennifer D. Ryan; Bradley R. Buchsbaum; Jennifer D. Ryan; Christa Dang; Michael B. Bone; Marie St-Laurent Eye movement reinstatement and neural reactivation during mental imagery Journal Article In: Cerebral Cortex, vol. 29, no. 3, pp. 1075–1089, 2018. @article{Bone2018, Half a century ago, Donald Hebb posited that mental imagery is a constructive process that emulates perception. Specifically, Hebb claimed that visual imagery results from the reactivation of neural activity associated with viewing images. He also argued that neural reactivation and imagery benefit from the re-enactment of eye movement patterns that first occurred at viewing (fixation reinstatement). To investigate these claims, we applied multivariate pattern analyses to functional MRI (fMRI) and eye-tracking data collected while healthy human participants repeatedly viewed and visualized complex images. We observed that the specificity of neural reactivation correlated positively with vivid imagery and with memory for stimulus image details. Moreover, neural reactivation correlated positively with fixation reinstatement, meaning that image-specific eye movements accompanied image-specific patterns of brain activity during visualization. These findings support the conception of mental imagery as a simulation of perception, and provide evidence of the supportive role of eye-movement in neural reactivation. |
Paul J. Boon; Silvia Zeni; Jan Theeuwes; Artem V. Belopolsky Rapid updating of spatial working memory across saccades Journal Article In: Scientific Reports, vol. 8, pp. 1072, 2018. @article{Boon2018, Each time we make an eye movement, positions of objects on the retina change. In order to keep track of relevant objects their positions have to be updated. The situation becomes even more complex if the object is no longer present in the world and has to be held in memory. In the present study, we used saccadic curvature to investigate the time-course of updating a memorized location across saccades. Previous studies have shown that a memorized location competes with a saccade target for selection on the oculomotor map, which leads to saccades curving away from it. In our study participants performed a sequence of two saccades while keeping a location in memory. The trajectory of the second saccade was used to measure when the memorized location was updated after the first saccade. The results showed that the memorized location was rapidly updated with the eyes curving away from its spatial coordinates within 130 ms after the first eye movement. The time-course of updating was comparable to the updating of an exogenously attended location, and depended on how well the location was memorized. |
Rudolf Burggraaf; Josef N. Geest; Maarten A. Frens; Ignace T. C. Hooge Visual search accelerates during adolescence Journal Article In: Journal of Vision, vol. 18, no. 5, pp. 1–11, 2018. @article{Burggraaf2018, We studied changes in visual-search performance and behavior during adolescence. Search performance was analyzed in terms of reaction time and response accuracy. Search behavior was analyzed in terms of the objects fixated and the duration of these fixations. A large group of adolescents (N ¼ 140; age: 12-19 years; 47% female, 53% male) participated in a visual-search experiment in which their eye movements were recorded with an eye tracker. The experiment consisted of 144 trials (50% with a target present), and participants had to decide whether a target was present. Each trial showed a search display with 36 Gabor patches placed on a hexagonal grid. The target was a vertically oriented element with a high spatial frequency. Nontargets differed from the target in spatial frequency, orientation, or both. Search performance and behavior changed during adolescence; with increasing age, fixation duration and reaction time decreased. Response accuracy, number of fixations, and selection of elements to fixate upon did not change with age. Thus, the speed of foveal discrimination increases with age, while the efficiency of peripheral selection does not change. We conclude that the way visual information is gathered does not change during adolescence, but the processing of visual information becomes faster. |
Pablo I. Burgos; Juan J. Mariman; Scott Makeig; Gonzalo Rivera-Lillo; Pedro E. Maldonado Visuomotor coordination and cortical connectivity of modular motor learning Journal Article In: Human Brain Mapping, vol. 39, no. 10, pp. 3836–3853, 2018. @article{Burgos2018, The ability to transfer sensorimotor skill components to new actions and the capacity to use skill components from whole actions are characteristic of the adaptability of the human sensorimotor system. However, behavioral evidence suggests complex limitations for transfer after combined or modular learning of motor adaptations. Also, to date, only behavioral analysis of the consequences of the modular learning has been reported, with little understanding of the sensorimotor mechanisms of control and the interaction between cortical areas. We programmed a video game with distorted kinematic and dynamic features to test the ability to combine sensorimotor skill components learned modularly (composition) and the capacity to use separate sensorimotor skill components learned in combination (decomposition). We examined motor performance, eye-hand coordination, and EEG connectivity. When tested for integrated learning, we found that combined practice initially performed better than separated practice, but differences disappeared after integrated practice. Separate learning promotes fewer anticipatory control mechanisms (depending more on feedback control), evidenced in a lower gaze leading behavior and in higher connectivity between visual and premotor domains, in comparison with the combined practice. The sensorimotor system can acquire motor modules in a separated or integrated manner. However, the system appears to require integrated practice to coordinate the adaptations with the skill learning and the networks involved in the integrated behavior. This integration seems to be related to the acquisition of anticipatory mechanism of control and with the decrement of feedback control. |
Sarah E. Burke; Immanuel Babu Henry Samuel; Qing Zhao; Jackson Cagle; Ronald A. Cohen; Benzi Kluger; Mingzhou Ding Task-based cognitive fatigability for older adults and validation of mental fatigability subscore of pittsburgh fatigability scale Journal Article In: Frontiers in Aging Neuroscience, vol. 10, pp. 327, 2018. @article{Burke2018, Cognitive fatigue and cognitive fatigability are distinct constructs. Cognitive fatigue reflects perception of cognitive fatigue outside of the context of activity level and duration and can be reliably assessed via established instruments such as the Fatigue Severity Scale (FSS) and the Modified Fatigue Impact Scale (MFIS). In contrast, cognitive fatigability reflects change in fatigue levels quantified within the context of the level and duration of cognitive activity, and currently there are no reliable measures of cognitive fatigability. A recently published scale, the Pittsburgh Fatigability Scale (PFS), attempts to remedy this problem with a focus on the aged population. While the physical fatigability subscore of PFS has been validated using physical activity derived measures, the mental fatigability subscore of PFS remains to be tested against equivalent measures derived from cognitive activities. To this end, we recruited 35 older, healthy adult participants (mean age 73.77 ± 5.9) to complete the PFS as well as a prolonged continuous performance of a Stroop task (>2 h). Task-based assessments included time-on-task changes in self-reported fatigue scores (every 20 min), reaction time, and pupil diameter. Defining subjective fatigability, behavioral fatigability, and physiologic/autonomic fatigability to be the slope of change over time-on-task in the above three assessed variables, we found that the PFS mental subscore was not correlated with any of the three task-based fatigability measures. Instead, the PFS mental subscore was correlated with trait level fatigue measures FSS (ρ = 0.63, p < 0.001), and MFIS cognitive subsection (ρ = 0.36 |
Clara Cámara; Cristina Malla; Joan López-Moliner; Eli Brenner Eye movements in interception with delayed visual feedback Journal Article In: Experimental Brain Research, vol. 236, no. 7, pp. 1837–1847, 2018. @article{Camara2018, The increased reliance on electronic devices such as smartphones in our everyday life exposes us to various delays between our actions and their consequences. Whereas it is known that people can adapt to such delays, the mechanisms underlying such adaptation remain unclear. To better understand these mechanisms, the current study explored the role of eye movements in interception with delayed visual feedback. In two experiments, eye movements were recorded as participants tried to intercept a moving target with their unseen finger while receiving delayed visual feedback about their own movement. In Experiment 1, the target randomly moved in one of two different directions at one of two different velocities. The delay between the participant's finger movement and movement of the cursor that provided feedback about the finger movements was gradually increased. Despite the delay, participants followed the target with their gaze. They were quite successful at hitting the target with the cursor. Thus, they moved their finger to a position that was ahead of where they were looking. Removing the feedback showed that participants had adapted to the delay. In Experiment 2, the target always moved in the same direction and at the same velocity, while the cursor's delay varied across trials. Participants still always directed their gaze at the target. They adjusted their movement to the delay on each trial, often succeeding to intercept the target with the cursor. Since their gaze was always directed at the target, and they could not know the delay until the cursor started moving, participants must have been using peripheral vision of the delayed cursor to guide it to the target. Thus, people deal with delays by directing their gaze at the target and using both experience from previous trials (Experiment 1) and peripheral visual information (Experiment 2) to guide their finger in a way that will make the cursor hit the target. |
Ian G. M. Cameron; Deanna L. Wallace; Ahmad Al-Zughoul; Andrew S. Kayser; Mark D'Esposito Effects of tolcapone and bromocriptine on cognitive stability and flexibility Journal Article In: Psychopharmacology, vol. 235, no. 4, pp. 1295–1305, 2018. @article{Cameron2018, Rationale: The prefrontal cortex (PFC) and basal ganglia (BG) have been associated with cognitive stability and cognitive flexibility, respectively. We hypothesized that increasing PFC dopamine tone by administering tolcapone (a catechol-O-methyltransferase (COMT) inhibitor) to human subjects should promote stability; conversely, increasing BG dopamine tone by administering bromocriptine (a D2 receptor agonist) should promote flexibility. Objective: We assessed these hypotheses by administering tolcapone, bromocriptine, and a placebo to healthy subjects who performed a saccadic eye movement task requiring stability and flexibility. Methods: We used a randomized, double-blind, within-subject design that was counterbalanced across drug administration sessions. In each session, subjects were cued to prepare for a pro-saccade (look towards a visual stimulus) or anti-saccade (look away) on every trial. On 60% of the trials, subjects were instructed to switch the response already in preparation. We hypothesized that flexibility would be required on switch trials, whereas stability would be required on non-switch trials. The primary measure of performance was efficiency (the percentage correct divided by reaction time for each trial type). Results: Subjects were significantly less efficient across all trial types under tolcapone, and there were no significant effects of bromocriptine. After grouping subjects based on Val158Met COMT polymorphism, we found that Met/Met and Val/Met subjects (greater PFC dopamine) were less efficient compared to Val/Val subjects. Conclusions: Optimal behavior was based on obeying the environmental stimuli, and we found reduced efficiency with greater PFC dopamine tone. We suggest that greater PFC dopamine interfered with the ability to flexibly follow the environment. |
Teng Cao; Lan Wang; Zhouyuan Sun; Stephen A. Engel; Sheng He The independent and shared mechanisms of intrinsic brain dynamics: Insights from bistable perception Journal Article In: Frontiers in Psychology, vol. 9, pp. 589, 2018. @article{Cao2018, In bistable perception, constant input leads to alternating perception. The dynamics of the changing perception reflects the intrinsic dynamic properties of the ‘unconscious inferential' process in the brain. Under the same condition, individuals differ in how fast they experience the perceptual alternation. In this study, testing many forms of bistable perception in a large number of observers, we investigated the key question of whether there is a general and common mechanism or multiple and independent mechanisms that control the dynamics of the inferential brain. Bistable phenomena tested include binocular rivalry, vase-face, Necker cube, moving plaid, motion induced blindness, biological motion, spinning dancer, rotating cylinder, Lissajous-figure, rolling wheel, and translating diamond. Switching dynamics for each bistable percept was measured in 100 observers. Results show that the switching rates of subsets of bistable percept are highly correlated. The clustering of dynamic properties of some bistable phenomena but not an overall general control of switching dynamics implies that the brain's inferential processes are both shared and independent – faster in constructing 3D structure from motion does not mean faster in integrating components into an objects. |
Irene Caprara; Peter Janssen; Maria C. Romero Investigating object representations in the macaque dorsal visual stream using single-unit recordings Journal Article In: Journal of Visualized Experiments, no. 138, pp. 1–10, 2018. @article{Caprara2018a, Previous studies have shown that neurons in parieto-frontal areas of the macaque brain can be highly selective for real-world objects, disparity-defined curved surfaces, and images of real-world objects (with and without disparity) in a similar manner as described in the ventral visual stream. In addition, parieto-frontal areas are believed to convert visual object information into appropriate motor outputs, such as the pre-shaping of the hand during grasping. To better characterize object selectivity in the cortical network involved in visuomotor transformations, we provide a battery of tests intended to analyze the visual object selectivity of neurons in parieto-frontal regions. |
Irene Caprara; Elsie Premereur; Maria C. Romero; Pedro Faria; Peter Janssen Shape responses in a macaque frontal area connected to posterior parietal cortex Journal Article In: NeuroImage, vol. 179, pp. 298–312, 2018. @article{Caprara2018, The primate dorsal visual stream processes object shape to guide actions involving an object, but the transmission of shape information beyond posterior parietal cortex remains largely unknown. To clarify the information flow between parietal and frontal cortex, we applied electrical microstimulation during functional Magnetic Resonance Imaging (fMRI) in a shape-selective patch in the posterior part of the Anterior Intraparietal area (pAIP) to chart its connectivity. Subsequently, we recorded single-unit responses to images of objects in the fMRI activation in prefrontal cortex, corresponding to area 45B, elicited by pAIP microstimulation. Neurons in area 45B had properties similar to neurons in pAIP, responding selectively to shape contours and to very small shape fragments measuring less than one deg at exceedingly short latencies. However, contrary to the prevailing view on the hierarchical organization of cortical areas, neurons in area 45B preferred even smaller shape fragments and had smaller receptive fields than neurons in pAIP. These findings provide the first evidence for ultra-fast shape processing in prefrontal cortex, and suggest that the pathway from pAIP to area 45B may not be important for object grasping. |
Christophe Carlei; Dirk Kerzel Stronger interference from distractors in the right hemifield during visual search Journal Article In: Laterality, vol. 23, no. 2, pp. 152–165, 2018. @article{Carlei2018, The orientation-bias hypothesis states that there is a bias to attend to the right visual hemifield (RVF) when there is spatial competition between stimuli in the left and right hemifield [Pollmann, S. (1996). A pop-out induced extinction-like phenomenon in neurologically intact subjects. Neuropsychologia, 34(5), 413?425. doi:10.1016/0028-3932(95)00125-5]. In support of this hypothesis, stronger interference was reported for RVF distractors with contralateral targets. In contrast, previous studies using rapid serial visual presentation (RSVP) found stronger interference from distractors in the left visual hemifield (LVF). We used the additional singleton paradigm to test whether this discrepancy was due to the different distractor features that were employed (colour vs. orientation). Interference from the colour distractor with contralateral targets was larger in the RVF than in the LVF. However, the asymmetrical interference disappeared when observers had to search for an inconspicuous colour target instead of the inconspicuous shape target. We suggest that the LVF orienting-bias is limited to situations where search is driven by bottom-up saliency (singleton search) instead of top-down search goals (feature search). In contrast, analysis of the literature suggests the opposite for the LVF bias in RSVP tasks. Thus, the attentional asymmetry may depend on whether the task involves temporal or spatial competition, and whether search is based on bottom-up or top-down signals. |
Thomas Carsten; Charlotte Desmet; Ruth M. Krebs; Marcel Brass Pupillary contagion is independent of the emotional expression of the face Journal Article In: Emotion, pp. 1–11, 2018. @article{Carsten2018, The concept of pupillary contagion refers to the automatic imitation of observed pupil size and reflects shared autonomic arousal. Previous studies have linked the experience of sadness to changes in pupil size. Accordingly, in a 2006 Social Cognitive and Affective Neuroscience article, Harrison, Singer, Rotshtein, Dolan, and Critchley found evidence for pupillary contagion when the observed face expressed sadness but not when it showed a neutral, happy, or angry expression. However, differences in eye movements might have influenced these results. Furthermore, the relatively small sample size of the study merits additional replication. In the current study, we modified the experimental design of Harrison et al. by requiring high attention toward the eye region of the face, which minimized differences in eye movements between facial expressions. In doing so, we demonstrate that the degree of pupillary contagion is independent of the observed emotional expression. Instead, pupil size and emotional expression of the shown face independently contribute to the observer's pupil size. The role of pupillary contagion for social communication is discussed. |
Tyler Cash-Padgett; Habiba Azab; Seng Bum Michael Yoo; Benjamin Y. Hayden Opposing pupil responses to offered and anticipated reward values Journal Article In: Animal Cognition, vol. 21, no. 5, pp. 671–684, 2018. @article{CashPadgett2018, Previous studies have shown that the pupils dilate more in anticipation of larger rewards. This finding raises the possibility of a more general association between reward amount and pupil size. We tested this idea by characterizing macaque pupil responses to offered rewards during evaluation and comparison in a binary choice task. To control attention, we made use of a design in which offers occurred in sequence. By looking at pupil responses after choice but before reward, we confirmed the previously observed positive association between pupil size and anticipated reward values. Surprisingly, however, we find that pupil size is negatively correlated with the value of offered gambles before choice, during both evaluation and comparison stages of the task. These results demonstrate a functional distinction between offered and anticipated rewards and present evidence against a narrow version of the simulation hypothesis; the idea that we represent offers by reactivating states associated with anticipating them. They also suggest that pupil size is correlated with relative, not absolute, values of offers, suggestive of an accept–reject model of comparison. |
Natalie Caspari; John T. Arsenault; Rik Vandenberghe; Wim Vanduffel Functional similarity of medial superior parietal areas for shift-selective attention signals in humans and monkeys Journal Article In: Cerebral Cortex, vol. 28, no. 6, pp. 2085–2099, 2018. @article{Caspari2018, We continually shift our attention between items in the visual environment. These attention shifts are usually based on task relevance (top-down) or the saliency of a sudden, unexpected stimulus (bottom-up), and are typically followed by goal-directed actions. It could be argued that any species that can covertly shift its focus of attention will rely on similar, evolutionarily conserved neural substrates for processing such shift-signals. To address this possibility, we performed comparative fMRI experiments in humans and monkeys, combining traditional, and novel, data-driven analytical approaches. Specifically, we examined correspondences between monkey and human brain areas activated during covert attention shifts. When " shift " events were compared with " stay " events, the medial (superior) parietal lobe (mSPL) and inferior parietal lobes showed similar shift sensitivities across species, whereas frontal activations were stronger in monkeys. To identify, in a data-driven manner, monkey regions that corresponded with human shift-selective SPL, we used a novel interspecies beta-correlation strategy whereby task-related beta-values were correlated across voxels or regions-of-interest in the 2 species. Monkey medial parietal areas V6/V6A most consistently correlated with shift-selective human mSPL. Our results indicate that both species recruit corresponding, evolutionarily conserved regions within the medial superior parietal lobe for shifting spatial attention. |
Monica S. Castelhano; Effie J. Pereira The influence of scene context on parafoveal processing of objects Journal Article In: Quarterly Journal of Experimental Psychology, vol. 71, no. 1, pp. 229–240, 2018. @article{Castelhano2018, Many studies in reading have shown the enhancing effect of context on the processing of a word before it is directly fixated (parafoveal processing of words; Balota et al., 1985; Balota & Rayner, 1983; Ehrlich & Rayner, 1981). Here, we examined whether scene context influences the parafoveal processing of objects and enhances the extraction of object information. Using a modified boundary paradigm (Rayner, 1975), the Dot-Boundary paradigm, participants fixated on a suddenly‐onsetting cue before the preview object would onset 4° away. The preview object could be identical to the target, visually similar, visually dissimilar, or a control (black rectangle). The preview changed to the target object once a saccade toward the object was made. Critically, the objects were presented on either a consistent or an inconsistent scene background. Results revealed that there was a greater processing benefit for consistent than inconsistent scene backgrounds and that identical and visually similar previews produced greater processing benefits than other previews. In the second experiment, we added an additional context condition in which the target location was inconsistent, but the scene semantics remained consistent. We found that changing the location of the target object disrupted the processing benefit derived from the consistent context. Most importantly, across both experiments, the effect of preview was not enhanced by scene context. Thus, preview information and scene context appear to independently boost the parafoveal processing of objects without any interaction from object-scene congruency. |
Kyle R. Cave; Tamaryn Menneer; Mohammad S. Nomani; Michael J. Stroud; Nick Donnelly Dual target search is neither purely simultaneous nor purely successive Journal Article In: Quarterly Journal of Experimental Psychology, vol. 71, no. 1, pp. 169–178, 2018. @article{Cave2018, Previous research shows that visual search for two different targets is less efficient than search for a single target. Stroud, Menneer, Cave and Donnelly (2012) concluded that two target colours are represented separately based on modeling the fixation patterns. Although those analyses provide evidence for two separate target representations, they do not show whether participants search simultaneously for both targets, or first search for one target and then the other. Some studies suggest that multiple target representations are simultaneously active, while others indicate that search can be voluntarily simultaneous, or switching, or a mixture of both. Stroud et al.'s participants were not explicitly instructed to use any particular strategy. These data were revisited to determine which strategy was employed. Each fixated item was categorised according to whether its colour was more similar to one target or the other. Once an item similar to one target is fixated, the next fixated item is more likely to be similar to that target than the other, showing that at a given moment during search, one target is generally favoured. However, the search for one target is not completed before search for the other begins. Instead, there are often short runs of one or two fixations to distractors similar to one target, with each run followed by a switch to the other target. Thus, the results suggest that one target is more highly weighted than the other at any given time, but not to the extent that search is purely successive. |
Bertrand Degos; Ilhame Ameqrane; Sophie Rivaud-Péchoux; Pierre Pouget; Marcus Missal Short-term temporal memory in idiopathic and Parkin-associated Parkinson's disease Journal Article In: Scientific Reports, vol. 8, pp. 7637, 2018. @article{Degos2018, In a rapidly changing environment, we often know when to do something before we have to do it. This preparation in the temporal domain is based on a ‘perception' of elapsed time and short-term memory of previous stimulation in a similar context. These functions could be perturbed in Parkinson's disease. Therefore, we investigated their role in eye movement preparation in sporadic Parkinson's disease and in a very infrequent variant affecting the Parkin gene. We used a simple oculomotor task where subjects had to orient to a visual target and movement latency was measured. We found that in spite of an increased average reaction time, the influence of elapsed time on movement preparation was similar in controls and the two groups of PD patients. However, short-term temporal memory of previous stimulation was severely affected in sporadic PD patients either ON or OFF dopaminergic therapy. We conclude that the two different contributions to temporal preparation could be dissociated. Moreover, a short-term temporal memory deficit might underlie temporal cognition deficits previously observed in PD. |
Tao Deng; Hongmei Yan; Yong-Jie Li Learning to boost bottom-up fixation prediction in driving environments via random forest Journal Article In: IEEE Transactions on Intelligent Transportation Systems, vol. 19, no. 9, pp. 3059–3067, 2018. @article{Deng2018, Saliency detection, an important step in many computer vision applications, can, for example, predict where drivers look in a vehicular traffic environment. While many bottom-up and top-down saliency detection models have been proposed for fixation prediction in outdoor scenes, no specific attempt has been made for traffic images. Here, we propose a learning saliency detection model based on a random forest (RF) to predict drivers' fixation positions in a driving environment. First, we extract low-level (color, intensity, orientation, etc.) and high-level (e.g., the vanishing point and center bias) features and then predict the fixation points via RF-based learning. Finally, we evaluate the performance of our saliency prediction model qualitatively and quantitatively. We use quantitative evaluation metrics that include the revised receiver operating characteristic (ROC), the area under the ROC curve value, and the normalized scan-path saliency score. The experimental results on real traffic images indicate that our model can more accurately predict a driver's fixation area, while driving than the state-of-the-art bottom-up saliency models. |
Rachel N. Denison; William T. Adler; Marisa Carrasco; Wei Ji Ma Humans incorporate attention-dependent uncertainty into perceptual decisions and confidence Journal Article In: Proceedings of the National Academy of Sciences, vol. 115, no. 43, pp. 11090–11095, 2018. @article{Denison2018, Perceptual decisions are better when they take uncertainty into account. Uncertainty arises not only from the properties of sensory input but also from cognitive sources, such as different levels of attention. However, it is unknown whether humans appropriately adjust for such cognitive sources of uncertainty during perceptual decision-making. Here we show that, in a task in which uncertainty is relevant for performance, human categorization and confidence decisions take into account uncertainty related to attention. We manipulated uncertainty in an orientation categorization task from trial to trial using only an attentional cue. The categorization task was designed to disambiguate decision rules that did or did not depend on attention. Using formal model comparison to evaluate decision behavior, we found that category and confidence decision boundaries shifted as a function of attention in an approximately Bayesian fashion. This means that the observer's attentional state on each trial contributed probabilistically to the decision computation. This responsiveness of an observer's decisions to attention-dependent uncertainty should improve perceptual decisions in natural vision, in which attention is unevenly distributed across a scene. |
Benjamin Denkinger; Madeline Kinn Own-age bias and positivity effects in facial recognition Journal Article In: Experimental Aging Research, vol. 44, no. 5, pp. 411–426, 2018. @article{Denkinger2018, Background/Study Context - In the current study, we evaluated two age-related differences in recognition memory: the own-age bias, wherein older and younger adults best recognize those of their own age group, and an age-related positivity effect, wherein older adults recall positive emotional information better than negative information relative to younger adults. We sought to extend previous research that jointly investigated these variables in recognition memory. Methods - Younger (age 18 – 27) and older (age 62 – 80) adults completed an incidental encoding task on a sequence of 50 positive, negative, or neutrally valenced images of older and younger adult faces. After a distractor task, participants made forced-choice recog- nition judgments and rated their decision confidence for images that were repeated with the same or a different emotional expression, and for novel, previously unseen faces. Results – Older and younger adults' recognition discriminability did not differ significantly between age groups. Notably, the data indi- cated an own-age bias in young adults, but not in older adults, and both age groups' recognition accuracy was greatest for faces that had originally been shown with a positive emotional expression. Conclusion - To our knowledge, this research is the first to demonstrate an own-age recognition bias in younger adults for emotional faces. Although our predictions of a differential impact by emotional faces on recognition of same and other-age faces were not supported, we identify a number of factors that contextualize these findings in the recent literature. |
Jonathan Denniss; Chris Scholes; Paul V. McGraw; Se-Ho Nam; Neil W. Roach Estimation of contrast sensitivity from fixational eye movements Journal Article In: Investigative Ophthalmology & Visual Science, vol. 59, no. 13, pp. 5408–5416, 2018. @article{Denniss2018, Purpose: Even during steady fixation, people make small eye movements such as microsaccades, whose rate is altered by presentation of salient stimuli. Our goal was to develop a practical method for objectively and robustly estimating contrast sensitivity from microsaccade rates in a diverse population. Methods: Participants, recruited to cover a range of contrast sensitivities, were visually normal (n = 19), amblyopic (n = 10), or had cataract (n = 9). Monocular contrast sensitivity was estimated behaviorally while binocular eye movements were recorded during interleaved passive trials. A probabilistic inference approach was used to establish the likelihood of observed microsaccade rates given the presence or absence of a salient stimulus. Contrast sensitivity was estimated from a function fitted to the scaled log-likelihood ratio of the observed microsaccades in the presence or absence of a salient stimulus across a range of contrasts. Results: Microsaccade rate signature shapes were heterogeneous; nevertheless, estimates of contrast sensitivity could be obtained in all participants. Microsaccade-estimated contrast sensitivity was unbiased compared to behavioral estimates (1.2% mean), with which they were strongly correlated (Spearman's rho 0.74, P < 0.001, median absolute difference 7.6%). Measurement precision of microsaccade-based contrast sensitivity estimates was worse than that of behavioral estimates, requiring more than 20 times as many presentations to equate precision. Conclusions: Microsaccade rate signatures are heterogeneous in shape when measured across populations with a broad range of contrast sensitivities. Contrast sensitivity can be robustly estimated from rate signatures by probabilistic inference, but more stimulus presentations are currently required to achieve similarly precise estimates to behavioral techniques. |
Nicolas Deravet; Gunnar Blohm; Jean-Jacques Orban Xivry; Philippe Lefèvre Weighted integration of short-term memory and sensory signals in the oculomotor system Journal Article In: Journal of Vision, vol. 18, no. 5, pp. 1–19, 2018. @article{Deravet2018, Oculomotor behaviors integrate sensory and prior information to overcome sensory-motor delays and noise. After much debate about this process, reliability-based integration has recently been proposed and several models of smooth pursuit now include recurrent Bayesian integration or Kalman filtering. However, there is a lack of behavioral evidence supporting these theoretical predictions. Here, we independently manipulated the reliability of visual and prior information in a smooth pursuit task. Our results show that both smooth pursuit eye velocity and catch-up saccade amplitude were modulated by visual and prior information reliability. We interpret these findings as the continuous reliability-based integration of a short-term memory of target motion with visual information, which support modelling work. Furthermore, we suggest that saccadic and pursuit systems share this short-term memory. We propose that this short-term memory of target motion is quickly built and continuously updated, and constitutes a general building-block present in all sensorimotor systems. |
Gerard Derosiere; Pierre-Alexandre Klein; Sylvie Nozaradan; Alexandre Zénon; André Mouraux; Julie Duque Visuomotor correlates of conflict expectation in the context of motor decisions Journal Article In: Journal of Neuroscience, vol. 38, no. 44, pp. 9486–9504, 2018. @article{Derosiere2018, Many behaviors require choosing between conflicting options competing against each other in visuomotor areas. Such choices can benefit from top-down control processes engaging frontal areas in advance of conflict when it is anticipated. Yet, very little is known about how this proactive control system shapes the visuomotor competition. Here, we used electroencephalography in human subjects (male and female) to identify the visual and motor correlates of conflict expectation in a version ofthe Eriksen Flanker task that required left or right responses according to the direction of a central target arrow surrounded by congruent or incongruent (conflicting) flankers. Visual conflict was either highly expected (it occurred in 80% of trials; mostly incongruent blocks) or very unlikely (20% of trials; mostly congruent blocks). We evaluated selective attention in the visual cortex by recording target- and flanker-related steady-state visual- evoked potentials (SSVEPs) and probed action selection by measuring response-locked potentials (RLPs) in the motor cortex. Conflict expectation enhanced accuracy in incongruent trials, but this improvement occurred at the cost ofspeed in congruent trials. Intriguingly, this behavioral adjustment occurred while visuomotor activity was less finely tuned: target-related SSVEPs were smaller while flanker related SSVEPs were higher in mostly incongruent blocks than in mostly congruent blocks, and incongruent trials were associated with larger RLPs in the ipsilateral (nonselected) motor cortex. Hence, our data suggest that conflict expectation recruits control processes that augment the tolerance for inappropriate visuomotor activations (rather than processes that down regulate their amplitude), allowing for overflow activity to occur without having it turn into the selection of an incorrect response. |
Moussa Diarra; Benjamin Rich Zendel; Jessica Benady‑Chorney; Caroll‑Ann Blanchette; Franco Lepore; Isabelle Peretz; Sylvie Belleville; Gregory L. West Playing Super Mario increases oculomotor inhibition and frontal eye field grey matter in older adults Journal Article In: Experimental Brain Research, pp. 1–11, 2018. @article{Diarra2018, Aging is associated with cognitive decline and decreased capacity to inhibit distracting information. Video game training holds promise to increase inhibitory mechanisms in older adults. In the current study, we tested the impact of 3D-platform video game training on performance in an antisaccade task and on related changes in grey matter within the frontal eye fields (FEFs) of older adults. An experimental group (VID group) engaged in 3D-platform video game training over a period of 6 months, while an active control group was trained on piano lessons (MUS group), and a no-contact control group did not participate in any intervention (CON group). Increased performance in oculomotor inhibition, as measured by the antisaccade task, and increased grey matter in the right FEF was observed uniquely in the VID group. These results demonstrate that 3D-platform video game training can improve inhibitory control known to decline with age. |
Katharina Dobs; Johannes Schultz; Isabelle Bülthoff; Justin L. Gardner Task-dependent enhancement of facial expression and identity representations in human cortex Journal Article In: NeuroImage, vol. 172, pp. 689–702, 2018. @article{Dobs2018, What cortical mechanisms allow humans to easily discern the expression or identity of a face? Subjects detected changes in expression or identity of a stream of dynamic faces while we measured BOLD responses from topographically and functionally defined areas throughout the visual hierarchy. Responses in dorsal areas increased during the expression task, whereas responses in ventral areas increased during the identity task, consistent with previous studies. Similar to ventral areas, early visual areas showed increased activity during the identity task. If visual responses are weighted by perceptual mechanisms according to their magnitude, these increased responses would lead to improved attentional selection of the task-appropriate facial aspect. Alternatively, increased responses could be a signature of a sensitivity enhancement mechanism that improves representations of the attended facial aspect. Consistent with the latter sensitivity enhancement mechanism, attending to expression led to enhanced decoding of exemplars of expression both in early visual and dorsal areas relative to attending identity. Similarly, decoding identity exemplars when attending to identity was improved in dorsal and ventral areas. We conclude that attending to expression or identity of dynamic faces is associated with increased selectivity in representations consistent with sensitivity enhancement. |
Samuel F. Dodge; Lina J. Karam Visual saliency prediction using a mixture of deep neural networks Journal Article In: IEEE Transactions on Image Processing, vol. 27, no. 8, pp. 4080–4090, 2018. @article{Dodge2018, Visual saliency models have recently begun to incorporate deep learning to achieve predictive capacity much greater than previous unsupervised methods. However, most existing models predict saliency without explicit knowledge of global scene semantic information. We propose a model (MxSalNet) that incorporates global scene semantic information in addition to local information gathered by a convolutional neural network. Our model is formulated as a mixture of experts. Each expert network is trained to predict saliency for a set of closely related images. The final saliency map is computed as a weighted mixture of the expert networks' output, with weights determined by a separate gating network. This gating network is guided by global scene information to predict weights. The expert networks and the gating network are trained simultaneously in an end-to-end manner. We show that our mixture formulation leads to improvement in performance over an otherwise identical non-mixture model that does not incorporate global scene information. Additionally, we show that our model achieves better performance than several other visual saliency models. |
Deborah A. Cronin; David E. Irwin Visual working memory supports perceptual stability across saccadic eye movements Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 44, no. 11, pp. 1739–1759, 2018. @article{Cronin2018, Vision is suppressed during saccadic eye movements. To create a stable perception of the visual world we must compensate for the gaps in visual input caused by this suppression. Some theories of perceptual stability, such as the Saccade Target Object Theory (McConkie & Currie, 1996), propose that stability relies on object correspondence across saccades. According to these views, the visual system encodes features of the saccade target into visual working memory (VWM) before a saccade is made. After the saccade, participants attempt to locate those features within a small region near the fovea. If this locating process succeeds, perceptual stability is maintained. The present study investigated directly whether perceptual stability relies on VWM. If it does, perceived stability should be impaired when VWM is loaded with other visual information. Participants detected saccade target displacements while simultaneously maintaining a VWM or verbal working memory (AWM) load. In three experiments, a VWM load negatively impacted participants' ability to detect saccade target displacements and the saccade target displacement task negatively impacted memory for VWM task items. Neither of these effects were apparent when AWM was loaded, suggesting that performance on VWM and saccade target displacement detection tasks, and thus perceptual stability, relies on VWM resources. |
Emily M. Crowe; Iain D. Gilchrist; Christopher Kent New approaches to the analysis of eye movement behaviour across expertise while viewing brain MRIs Journal Article In: Cognitive Research: Principles and Implications, vol. 3, pp. 1–14, 2018. @article{Crowe2018, Brain tumour detection and diagnosis requires clinicians to inspect and analyse brain magnetic resonance images. Eye-tracking is commonly used to examine observers' gaze behaviour during such medical image interpretation tasks, but analysis of eye movement sequences is limited. We therefore used ScanMatch, a novel technique that compares saccadic eye movement sequences, to examine the effect of expertise and diagnosis on the similarity of scanning patterns. Diagnostic accuracy was also recorded. Thirty-five participants were classified as Novices, Medics and Experts based on their level of expertise. Participants completed two brain tumour detection tasks. The first was a whole-brain task, which consisted of 60 consecutively presented slices from one patient; the second was an independent-slice detection task, which consisted of 32 independent slices from five different patients. Experts displayed the highest accuracy and sensitivity followed by Medics and then Novices in the independent-slice task. Experts showed the highest level of scanning pattern similarity, with medics engaging in the least similar scanning patterns, for both the whole-brain and independent-slice task. In the independent-slice task, scanning patterns were the least similar for false negatives across all expertise levels and most similar for experts when they responded correctly. These results demonstrate the value of using ScanMatch in the medical image perception literature. Future research adopting this tool could, for example, identify cases that yield low scanning similarity and so provide insight into why diagnostic errors occur and ultimately help in training radiologists. |
Elizabeth K. Cutrone; David J. Heeger; Marisa Carrasco On spatial attention and its field size on the repulsion effect Journal Article In: Journal of Vision, vol. 18, no. 6, pp. 1–15, 2018. @article{Cutrone2018, We investigated the attentional repulsion effect-stimuli appear displaced further away from attended locations-in three experiments: one with exogenous (involuntary) attention, and two with endogenous (voluntary) attention with different attention-field sizes. It has been proposed that differences in attention-field size can account for qualitative differences in neural responses elicited by attended stimuli. We used psychophysical comparative judgments and manipulated either exogenous attention via peripheral cues or endogenous attention via central cues and a demanding rapid serial visual presentation task. We manipulated the attention field size of endogenous attention by presenting streams of letters at two specific locations or at two of many possible locations during each block. We found a robust attentional repulsion effect in all three experiments: with endogenous and exogenous attention and with both attention-field sizes. These findings advance our understanding of the influence of spatial attention on the perception of visual space and help relate this repulsion effect to possible neurophysiological correlates. |
Marshall A. Dalton; Peter Zeidman; Cornelia McCormick; Eleanor A. Maguire Differentiable processing of objects, associations, and scenes within the hippocampus Journal Article In: Journal of Neuroscience, vol. 38, no. 38, pp. 8146–8159, 2018. @article{Dalton2018, The hippocampus is known to be important for a range of cognitive functions including episodic memory, spatial navigation and future-thinking. Wide agreement on the exact nature of its contribution has proved elusive, with some theories emphasising associative processes and another proposing that scene construction is its primary role. To directly compare these accounts of hippocampal function in human males and females, we devised a novel mental imagery paradigm where different tasks were closely matched for associative processing and mental construction, but either did or did not evoke scene representations, and we combined this with high resolution functional MRI. The results were striking in showing that differentiable parts of the hippocampus, along with distinct cortical regions, were recruited for scene construction or non-scene-evoking associative processing. The contrasting patterns of neural engagement could not be accounted for by differences in eye movements, mnemonic processing or the phenomenology of mental imagery. These results inform conceptual debates in the field by showing that the hippocampus does not seem to favour one type of process over another; it is not a story of exclusivity. Rather, there may be different circuits within the hippocampus, each associated with different cortical inputs, which become engaged depending on the nature of the stimuli and the task at hand. Overall, our findings emphasise the importance of considering the hippocampus as a heterogeneous structure, and that a focus on characterising how specific portions of the hippocampus interact with other brain regions may promote a better understanding of its role in cognition. |
Jean-Bernard Damasse; Laurent U. Perrinet; Laurent Madelain; Anna Montagnini Reinforcement effects in anticipatory smooth eye movements Journal Article In: Journal of Vision, vol. 18, no. 11, pp. 1–18, 2018. @article{Damasse2018, When predictive information about target motion is available, anticipatory smooth pursuit eye movements (aSPEM) are consistently generated before target appearance, thereby reducing the typical sensorimotor delay between target motion onset and foveation.By manipulating the probability for target motion direction, we were able to bias the direction and mean velocity of aSPEM. This suggests that motion-direction expectancy has a strong effect on the initiation of anticipatory movements. To further understand the nature of anticipatory smooth eye movements, we investigated different effects of reinforcement on aSPEM. In a first experiment, the reinforcement was contingent to a particular anticipatory behavior. A monetary reward was associated to a criterion-matching anticipatory velocity as estimated online during the gap before target motion onset. Our results showed a small but significant effect of behavior-contingent monetary reward on aSPEM. In a second experiment, the proportion of rewarded trials was manipulated across motion directions (right vs. left) independently from participants' behavior. Our results indicate that a bias in expected reward does not systematically affect anticipatory eye movements. Overall, these findings strengthen the notion that anticipatory eye movements can be considered as an operant behavior (similar to visually guided ones), whereas the expectancy for a noncontingent reward cannot efficiently bias them. |
James Danckert; Tina Hammerschmidt; Jeremy Marty-Dugas; Daniel Smilek Boredom: Under-aroused and restless Journal Article In: Consciousness and Cognition, vol. 61, pp. 24–37, 2018. @article{Danckert2018, Boredom is a common experience associated with a range of negative outcomes. Debate remains as to whether boredom should be considered a high or low arousal state. We employed passages of text to induce either boredom or interest and probed self-reported levels of boredom, arousal, and restlessness. Results replicated known associations between mind-wandering and state boredom (i.e., mind-wandering was highest for the boredom mood induction). Reports of sleepiness (a proxy for arousal level) were highest for the boring induction. While restlessness was not different for the boring and interesting inductions when they were performed first, restlessness was significantly higher for the boredom induction when it was experienced last. We discuss these results within the context of the debate regarding boredom and arousal. |
Frederic R. Danion; J. Randall Flanagan Different gaze strategies during eye versus hand tracking of a moving target Journal Article In: Scientific Reports, vol. 8, pp. 10059, 2018. @article{Danion2018, The ability to visually track, using smooth pursuit eye movements, moving objects is critical in both perceptual and action tasks. Here, by asking participants to view a moving target or track it with their hand, we tested whether different task demands give rise to different gaze strategies. We hypothesized that during hand tracking, in comparison to eye tracking, the frequency of catch-up saccades would be lower, and the smooth pursuit gain would be greater, because it limits the loss of stable retinal and extra-retinal information due to saccades. In our study participants viewed a visual target that followed a smooth but unpredictable trajectory in a horizontal plane and were instructed to either track the target with their gaze or with a cursor controlled by a manipulandum. Although the mean distance between gaze and target was comparable in both tasks, we found, consistent with our hypothesis, an increase in smooth pursuit gain and a decrease in the frequency of catch-up saccades during hand tracking. We suggest that this difference in gaze behavior arises from different tasks demands. Whereas keeping gaze close to the target is important in both tasks, obtaining stable retinal and extra-retinal information is critical for guiding hand movement. |
Ravi K. Das; Grace Gale; Vanessa Hennessy; Sunjeev K. Kamboj A prediction error-driven retrieval procedure for destabilizing and rewriting maladaptive reward memories in hazardous drinkers Journal Article In: Journal of Visualized Experiments, no. 131, pp. 1–12, 2018. @article{Das2018, Maladaptive reward memories (MRMs) can become unstable following retrieval under certain conditions, allowing their modification by subsequent new learning. However, robust (well-rehearsed) and chronologically old MRMs, such as those underlying substance use disorders, do not destabilize easily when retrieved. A key determinate of memory destabilization during retrieval is prediction error (PE). We describe a retrieval procedure for alcohol MRMs in hazardous drinkers that specifically aims to maximize the generation of PE and therefore the likelihood of MRM destabilization. The procedure requires explicitly generating the expectancy of alcohol consumption and then violating this expectancy (withholding alcohol) following the presentation of a brief set of prototypical alcohol cue images (retrieval + PE). Control procedures involve presenting the same cue images, but allow alcohol to be consumed, generating minimal PE (retrieval-no PE) or generate PE without retrieval of alcohol MRMs, by presenting orange juice cues (no retrieval + PE). Subsequently, we describe a multisensory disgust-based counterconditioning procedure to probe MRM destabilization by re-writing alcohol cue-reward associations prior to reconsolidation. This procedure pairs alcohol cues with images invoking pathogen disgust and an extremely bitter-tasting solution (denatonium benzoate), generating gustatory disgust. Following retrieval + PE, but not no retrieval + PE or retrieval-no PE, counterconditioning produces evidence of MRM rewriting as indexed by lasting reductions in alcohol cue valuation, attentional capture, and alcohol craving. |
Fabian J. David; Lisa C. Goelz; Ruth Z. Tangonan; Leonard Verhagen Metman; Daniel M. Corcos Bilateral deep brain stimulation of the subthalamic nucleus increases pointing error during memory-guided sequential reaching Journal Article In: Experimental Brain Research, vol. 236, no. 4, pp. 1053–1065, 2018. @article{David2018, Deep brain stimulation of the subthalamic nucleus (STN DBS) significantly improves clinical motor symptoms, as well as intensive aspects of movement like velocity and amplitude in patients with Parkinson's disease (PD). However, the effects of bilateral STN DBS on integrative and coordinative aspects of motor control are equivocal. The aim of this study was to investigate the effects of bilateral STN DBS on integrative and coordinative aspects of movement using a memory-guided sequential reaching task. The primary outcomes were eye and finger velocity and end-point error. We expected that bilateral STN DBS would increase reaching velocity. More importantly, we hypothesized that bilateral STN DBS would increase eye and finger end-point error and this would not simply be the result of a speed accuracy trade-off. Ten patients with PD and bilaterally implanted subthalamic stimulators performed a memory-guided sequential reaching task under four stimulator conditions (DBS-OFF, DBS-LEFT, DBS-RIGHT, and DBS-BILATERAL) over 4 days. DBS-BILATERAL significantly increased eye velocity compared to DBS-OFF, DBS-LEFT, and DBS-RIGHT. It also increased finger velocity compared to DBS-OFF and DBS-RIGHT. DBS-BILATERAL did not change eye end-point error. The novel finding was that DBS-BILATERAL increased finger end-point error compared to DBS-OFF, DBS-LEFT, and DBS-RIGHT even after adjusting for differences in velocity. We conclude that bilateral STN DBS may facilitate basal ganglia–cortical networks that underlie intensive aspects of movement like velocity, but it may disrupt selective basal ganglia–cortical networks that underlie certain integrative and coordinative aspects of movement such as spatial accuracy. |
Anouk J. Brouwer; Mohammed Albaghdadi; J. Randall Flanagan; Jason P. Gallivan Using gaze behavior to parcellate the explicit and implicit contributions to visuomotor learning Journal Article In: Journal of Neurophysiology, vol. 120, no. 4, pp. 1602–1615, 2018. @article{Brouwer2018, Successful motor performance relies on our ability to adapt to changes in the environment by learning novel mappings between motor commands and sensory outcomes. Such adaptation is thought to involve two distinct mechanisms: an implicit, error-based component linked to slow learning and an explicit, strategic component linked to fast learning and savings (i.e., faster relearning). Because behavior, at any given moment, is the resultant combination of these two processes, it has remained a challenge to parcellate their relative contributions to performance. The explicit component to visuomotor rotation (VMR) learning has recently been measured by having participants verbally report their aiming strategy used to counteract the rotation. However, this procedure has been shown to magnify the explicit component. Here we tested whether task-specific eye movements, a natural component of reach planning, but poorly studied in motor learning tasks, can provide a direct readout of the state of the explicit component during VMR learning. We show, by placing targets on a visible ring and including a delay between target presentation and reach onset, that individual differences in gaze patterns during sensorimotor learning are linked to participants' rates of learning and their expression of savings. Specifically, we find that participants who, during reach planning, naturally fixate an aimpoint rotated away from the target location, show faster initial adaptation and readaptation 24 h later. Our results demonstrate that gaze behavior cannot only uniquely identify individuals who implement cognitive strategies during learning but also how their implementation is linked to differences in learning. |
Anouk J. Brouwer; Jason P. Gallivan; J. Randall Flanagan Visuomotor feedback gains are modulated by gaze position Journal Article In: Journal of Neurophysiology, vol. 120, no. 5, pp. 2522–2531, 2018. @article{Brouwer2018a, During goal-directed reaching, people typically direct their gaze to the target before the start of the hand movement and maintain fixation until the hand arrives. This gaze strategy improves reach accuracy in two ways. It enables the use of central vision at the end of movement, and it allows the use of extraretinal information in guiding the hand to the target. Here we tested whether fixating the reach target further facilitates reach accuracy by optimizing the use of peripheral vision in detecting, and rapidly responding to, reach errors during the ongoing movement. We examined automatic visuomotor corrections in response to displacements of the cursor representing the hand position as a function of gaze fixation location during unimanual goal-directed reaching. Eight fixation targets were positioned either in line with, or at different angles relative to, the straight-ahead movement direction (manipulation of fixation angle), and at different distances from the location of the visual perturbation (manipulation of fixation distance). We found that corrections were fastest and strongest when gaze was directed at the reach target compared with when gaze was directed to a different location in the workspace. We found that the gain of the visuomotor response was strongly affected by fixation angle, and to a smaller extent by fixation distance, with lower gains as the angle or distance increased. We submit that fixating the reach target improves reach accuracy by facilitating rapid visuomotor responses to reach errors viewed in peripheral vision. |
Michelle I. C. Haan; Sonja Wel; Renée M. Visser; H. Steven Scholte; Guido A. Wingen; Merel Kindt The influence of acoustic startle probes on fear learning in humans Journal Article In: Scientific Reports, vol. 8, pp. 14552, 2018. @article{Haan2018, Even though human fear-conditioning involves affective learning as well as expectancy learning, most studies assess only one of the two distinct processes. Commonly used read-outs of associative fear learning are the fear-potentiated startle reflex (FPS), pupil dilation and US-expectancy ratings. FPS is thought to reflect the affective aspect of fear learning, while pupil dilation reflects a general arousal response. However, in order to measure FPS, aversively loud acoustic probes are presented during conditioning, which might in itself exert an effect on fear learning. Here we tested the effect of startle probes on fear learning by comparing brain activation (fMRI), pupil dilation and US-expectancy ratings with and without acoustic startle probes within subjects. Regardless of startle probes, fear conditioning resulted in enhanced dACC, insula and ventral striatum activation. Interaction analyses showed that startle probes diminished differential pupil dilation between CS+ and CS− due to increased pupil responses to CS−. A trend significant interaction effect was observed for US-expectancy and amygdala activation. Startle probes affect differential fear learning by impeding safety learning, as measured with pupil dilation, a read-out of the cognitive component of fear learning. However, we observed no significant effect of acoustic startle probes on other measures of fear learning. |
Benjamin Haas; Dietrich Samuel Schwarzkopf Spatially selective responses to Kanizsa and occlusion stimuli in human visual cortex Journal Article In: Scientific Reports, vol. 8, pp. 611, 2018. @article{Haas2018, Early visual cortex responds to illusory contours in which abutting lines or collinear edges imply the presence of an occluding surface, as well as to occluded parts of an object. Here we used functional magnetic resonance imaging (fMRI) and population receptive field (pRF) analysis to map retinotopic responses in early visual cortex using bar stimuli defined by illusory contours, occluded parts of a bar, or subtle luminance contrast. All conditions produced retinotopic responses in early visual field maps even though signal-to-noise ratios were very low. We found that signal-to-noise ratios and coherence with independent high-contrast mapping data increased from V1 to V2 to V3. Moreover, we found no differences of signal-to-noise ratios or pRF sizes between the low-contrast luminance and illusion conditions. We propose that all three conditions mapped spatial attention to the bar location rather than activations specifically related to illusory contours or occlusion. |
Yehudit Botschko; Merav Yarkoni; Mati Joshua Smooth pursuit eye movement of monkeys naive to laboratory setups with pictures and artificial stimuli Journal Article In: Frontiers in Systems Neuroscience, vol. 12, pp. 15, 2018. @article{Botschko2018, When animal behavior is studied in a laboratory environment, the animals are often extensively trained to shape their behavior. A crucial question is whether the behavior observed after training is part of the natural repertoire of the animal or represents an outlier in the animal's natural capabilities. This can be investigated by assessing the extent to which the target behavior is manifested during the initial stages of training and the time course of learning. We explored this issue by examining smooth pursuit eye movements in monkeys naïve to smooth pursuit tasks. We recorded the eye movements of monkeys from the first days of training on a step-ramp paradigm. We used bright spots, monkey pictures and scrambled versions of the pictures as moving targets. We found that during the initial stages of training, the pursuit initiation was largest for the monkey pictures and in some direction conditions close to target velocity. When the pursuit initiation was large, the monkeys mostly continued to track the target with smooth pursuit movements while correcting for displacement errors with small saccades. Two weeks of training increased the pursuit eye velocity in all stimulus conditions, whereas further extensive training enhanced pursuit slightly more. The training decreased the coefficient of variation of the eye velocity. Anisotropies that grade pursuit across directions were observed from the first day of training and mostly persisted across training. Thus, smooth pursuit in the step-ramp paradigm appears to be part of the natural repertoire of monkeys' behavior and training adjusts monkeys' natural predisposed behavior. |
Jessica Bourgin; Nathalie Guyader; Alan Chauvin; Alexandra Juphard; Mathilde Sauvée; Olivier Moreaud; Laetitia Silvert; Pascal Hot Early emotional attention is impacted in Alzheimer's disease: An eye-tracking study Journal Article In: Journal of Alzheimer's Disease, vol. 63, no. 4, pp. 1445–1458, 2018. @article{Bourgin2018, Emotional deficits have been repetitively reported in Alzheimer's disease (AD) without clearly identifying how emotional processing is impaired in this pathology. This paper describes an investigation of early emotional processing, as measured by the effects of emotional visual stimuli on a saccadic task involving both pro (PS) and anti (AS) saccades. Sixteen patients with AD and 25 age-matched healthy controls were eye-tracked while they had to quickly move their gaze toward a positive, negative, or neutral image presented on a computer screen (in the PS condition) or away from the image (in the AS condition). The age-matched controls made more AS mistakes for negative stimuli than for other stimuli, and triggered PSs toward negative stimuli more quickly than toward other stimuli. In contrast, patients with AD showed no difference with regard to the emotional category in any of the tasks. The present study is the first to highlight a lack of early emotional attention in patients with AD. These results should be taken into account in the care provided to patients with AD, since this early impairment might seriously degrade their overall emotional functioning. |
Luc Boutsen; Nathan A. Pearson; Martin Jüttner Differential impact of disfiguring facial features on overt and covert attention Journal Article In: Acta Psychologica, vol. 190, pp. 122–134, 2018. @article{Boutsen2018, Observers can form negative impressions about faces that contain disfiguring features (e.g., scars). Previous research suggests that this might be due to the ability of disfiguring features to capture attention — as evidenced by contrasting observers' responses to faces with or without disfiguring features. This, however, confounds the effects of salience and perceptual interpretation, i.e. whether the feature is seen as integral to the face, or separate from it. Furthermore, it remains unclear to what extent disfiguring features influence covert as well as overt attention. We addressed these issues by studying attentional effects by photographs of unfamiliar faces containing a unilateral disfigurement (a skin discoloration) or a visually similar control feature that was partly occluding the face. Disfiguring and occluding features were first matched for salience (Experiment 1). Experiments 2 and 3 assessed the effect of these features on covert attention in two cueing tasks involving discrimination of a (validly or invalidly cued) target in the presence of, respectively, a peripheral or central distractor face. In both conditions, disfigured and occluded faces did not differ significantly in their impact on response-time costs following invalid cues. In Experiment 4 we compared overt attention to these faces by analysing patterns of eye fixations during an attractiveness rating task. Critically, faces with disfiguring features attracted more fixations on the eyes and incurred a higher number of recurrent fixations compared to faces with salience-matched occluding features. Together, these results suggest a differential impact of disfiguring facial features on overt and covert attention, which is mediated both by the visual salience of such features and by their perceptual interpretation. |
Stanislas Boyer; Pierre-Vincent Paubel; Robert Ruiz; Radouane El Yagoubi; Agnès Daurat Human voice as a measure of mental load level Journal Article In: Journal of Speech, Language, and Hearing Research, vol. 61, no. 11, pp. 2722–2734, 2018. @article{Boyer2018, Purpose: The aim of this study was to determine a reliable and efficient set of acoustic parameters of the human voice able to estimate individuals' mental load level. Implementing detection methods and real-time analysis of mental load is a major challenge for monitoring and enhancing human task performance, especially during high-risk activities (e.g., flying aircraft). Method: The voices of 32 participants were recorded during a cognitive task featuring word list recall. The difficulty of the task was manipulated by varying the number of words in each list (i.e., between 1 and 7, corresponding to 7 mental load conditions). Evoked pupillary response, known to be a useful proxy of mental load, was recorded simultaneously with speech to attest variations in mental load level during the experimental task. Results: Classic features (fundamental frequency, its standard deviation, number of periods) and original features (frequency modulation and short-term variation in digital amplitude length) of the acoustic signals were predictive of memory load condition. They varied significantly according to the number of words to recall, specifically beyond a threshold of 3-5 words to recall, that is, when memory performance started to decline. Conclusions: Some acoustic parameters of the human voice could be an appropriate and efficient means for detecting mental load levels. |
James A. Brissenden; Sean M. Tobyne; David E. Osher; Emily J. Levin; Mark A. Halko; David C. Somers Topographic cortico-cerebellar networks revealed by visual attention and working memory Journal Article In: Current Biology, vol. 28, pp. 3364–3372, 2018. @article{Brissenden2018, Substantial portions of the cerebellum appear to support non-motor functions; however, previous investigations of cerebellar involvement in cognition have revealed only a coarse degree of specificity. Although somatotopic maps have been observed within cerebellum, similar precision within corticocerebellar networks supporting non-motor functions has not previously been reported. Here, we find that human cerebellar lobule VIIb/VIIIa differentially codes key aspects of visuospatial cognition. Ipsilateral visuospatial representations were observed during both a visual working memory and an attentionally demanding visual receptive field-mapping fMRI task paradigm. Moreover, within lobule VIIb/VIIIa, we observed a functional dissociation between spatial coding and visual working memory processing. Visuospatial representations were found in the dorsomedial portion of lobule VIIb/VIIIa, and load dependent visual working memory processing was shifted ventrolaterally. A similar functional gradient for spatial versus load processing was found in posterior parietal cortex. This cerebral cortical organization was well predicted by functional connectivity with spatial and load regions of cerebellar lobule VIIb/VIIIa. Collectively, our findings indicate that recruitment by visuospatial attentional functions within cerebellar lobule VIIb/VIIIa is highly specific. Furthermore, the topographic arrangement of these functions is mirrored in frontal and parietal cortex. These findings motivate a closer examination of cortico-cerebellar functional specialization across a broad range of cognitive domains. |
Andreas Brocher; Raphael Harbecke; Tim Graf; Daniel Memmert; Stefanie Hüttermann Using task effort and pupil size to track covert shifts of visual attention independently of a pupillary light reflex Journal Article In: Behavior Research Methods, vol. 50, no. 6, pp. 2551–2567, 2018. @article{Brocher2018b, We tested the link between pupil size and the task effort involved in covert shifts of visual attention. The goal of this study was to establish pupil size as a marker of attentional shifting in the absence of luminance manipulations. In three experiments, participants evaluated two stimuli that were presented peripherally, appearing equidistant from and on opposite sides of eye fixation. The angle between eye fixation and the peripherally presented target stimuli varied from 12.5 degrees to 42.5 degrees . The evaluation of more distant stimuli led to poorer performance than did the evaluation of more proximal stimuli throughout our study, confirming that the former required more effort than the latter. In addition, in Experiment 1 we found that pupil size increased with increasing angle and that this effect could not be reduced to the operation of low-level visual processes in the task. In Experiment 2 the pupil dilated more strongly overall when participants evaluated the target stimuli, which required shifts of attention, than when they merely reported on the target's presence versus absence. Both conditions yielded larger pupils for more distant than for more proximal stimuli, however. In Experiment 3, we manipulated task difficulty more directly, by changing the contrast at which the target stimuli were presented. We replicated the results from Experiment 1 only with the high-contrast stimuli. With stimuli of low contrast, ceiling effects in pupil size were observed. Our data show that the link between task effort and pupil size can be used to track the degree to which an observer covertly shifts attention to or detects stimuli in peripheral vision. |
Garvin Brod; Marcus Hasselhorn; Silvia A. Bunge When generating a prediction boosts learning: The element of surprise Journal Article In: Learning and Instruction, vol. 55, pp. 22–31, 2018. @article{Brod2018, Using both behavioral and eye-tracking methodology, we tested whether and how asking students to generate predictions is an efficient technique to improve learning. In particular, we designed two tasks to test whether the surprise induced by outcomes that violate expectations enhances learning. Data from the first task revealed that asking participants to generate predictions, as compared to making post hoc evaluations, facilitated acquisition of geography knowledge. Pupillometry measurements revealed that expectancy-violating outcomes led to a surprise response only when a prediction was made beforehand, and that the strength of this response was positively related to the amount of learning. Data from the second task demonstrated that making predictions about the outcomes of soccer matches specifically improved memory for expectancy-violating events. These results suggest that a specific benefit of making predictions in learning contexts is that it creates the opportunity for the learner to be surprised. Implications for theory and educational practice are discussed. |
Rotem Broday-Dvir; Shany Grossman; Edna Furman-Haran; Rafael Malach Quenching of spontaneous fluctuations by attention in human visual cortex Journal Article In: NeuroImage, vol. 171, pp. 84–98, 2018. @article{BrodayDvir2018, In the absence of a task, the human brain enters a mode of slow spontaneous fluctuations. A fundamental, unresolved question is whether these fluctuations are ongoing and thus persist during task engagement, or alternatively, are quenched and replaced by task-related activations. Here, we examined this issue in the human visual cortex, using fMRI. Participants were asked to either perform a recognition task of randomly appearing face and non-face targets (attended condition) or watch them passively (unattended condition). Importantly, in approximately half of the trials, all sensory stimuli were absent. Our results show that even in the absence of stimuli, spontaneous fluctuations were suppressed by attention. The effect occurred in early visual cortex as well as in fronto-parietal attention network regions. During unattended trials, the activity fluctuations were negatively linked to pupil diameter, arguing against attentional fluctuations as underlying the effect. The results demonstrate that spontaneous fluctuations do not remain unchanged with task performance, but are rather modulated according to behavioral and cognitive demands. |
Suzon Ajasse; Ryad B. Benosman; Jean Lorenceau Effects of pupillary responses to luminance and attention on visual spatial discrimination Journal Article In: Journal of Vision, vol. 18, no. 11, pp. 1–14, 2018. @article{Ajasse2018, The optic quality of the eyes is, at least in part, determined by pupil size. Large pupils let more light enter the eyes, but degrade the point spread function, and thus the spatial resolution that can be achieved (Campbell & Gregory, 1960). In natural conditions, the pupil is mainly driven by the luminance (and possibly the color and contrast) at the gazed location, but is also modulated by attention and cognitive factors. Whether changes in eyes' optics related to pupil size modulation by luminance and attention impacts visual processing was assessed in two experiments. In Experiment 1, we measured pupil size using a constantly visible display made of four disks with different luminance levels, with no other task than fixating the disks in succession. The results confirmed that pupil size depends on the luminance of the gazed stimulus. Experiment 2, using similar settings as Experiment 1, used a two-interval forced-choice design to test whether discriminating high spatial frequencies that requires covert attention to parafoveal stimuli is better during the fixation of bright disks that entails a small pupil size, and hence better eyes' optics, as compared to fixating dark disks that entails a large pupil size, and hence poorer eyes' optics. As in Experiment 1, we observed large modulations of pupil size depending on the luminance of the gazed stimulus, but pupil dynamics was more variable, with marked pupil dilation during stimulus encoding, presumably because the demanding spatial frequency discrimination task engaged attention. However, discrimination performance and mean pupil size were not correlated. Despite this lack of correlation, the slopes of pupil dilation during stimulus encoding were correlated to performance, while the slopes of pupil dilation during decision-making were not. We discuss these results regarding the possible functional roles of pupil size modulations. |
Sara Ajina; Holly Bridge Blindsight relies on a functional connection between hMT+ and the lateral geniculate nucleus, not the pulvinar Journal Article In: PLoS Biology, vol. 16, no. 7, pp. e2005769, 2018. @article{Ajina2018, When the primary visual cortex (V1) is damaged, the principal visual pathway is lost, causing a loss of vision in the opposite visual field. While conscious vision is impaired, patients can still respond to certain images; this is known as ‘blindsight'. Recently, a direct anatomical connection between the lateral geniculate nucleus (LGN) and human motion area hMT+ has been implicated in blindsight. However, a functional connection between these structures has not been demonstrated. We quantified functional MRI responses to motion in 14 patients with unilateral V1 damage (with and without blindsight). Patients with blindsight showed significant activity and a preserved sensitivity to speed in motion area hMT+, which was absent in patients without blindsight. We then compared functional connectivity between motion area hMT+ and a number of structures implicated in blindsight, including the ventral pulvinar. Only patients with blindsight showed an intact functional connection with the LGN but not the other structures, supporting a specific functional role for the LGN in blindsight. |
Andrea Alamia; Oleg Solopchuk; Alexandre Zénon Strong conscious cues suppress preferential gaze allocation to unconscious cues Journal Article In: Frontiers in Human Neuroscience, vol. 12, pp. 427, 2018. @article{Alamia2018, Visual attention allows relevant information to be selected for further processing. Both conscious and unconscious visual stimuli can bias attentional allocation, but how these two types of visual information interact to guide attention remains unclear. In this study, we explored attentional allocation during a motion discrimination task with varied motion strength and unconscious associations between stimuli and cues. Participants were instructed to report the motion direction of two colored patches of dots. Unbeknown to participants, dot colors were sometimes informative of the correct response. We found that subjects learnt the associations between colors and motion direction but failed to report this association using the questionnaire filled at the end of the experiment, confirming that learning remained unconscious. The eye movement analyses revealed that allocation of attention to unconscious sources of information occurred mostly when motion coherence was low, indicating that unconscious cues influence attentional allocation only in the absence of strong conscious cues. All in all, our results reveal that conscious and unconscious sources of information interact with each other to influence attentional allocation and suggest a selection process that weights cues in proportion to their reliability. |
Concetta F. Alberti; Peter J. Bex Binocular contrast summation and inhibition depends on spatial frequency, eccentricity and binocular disparity Journal Article In: Ophthalmic and Physiological Optics, vol. 38, no. 5, pp. 525–537, 2018. @article{Alberti2018, Purpose: When central vision is compromised, visually-guided behaviour becomes dependent on peripheral retina, often at a preferred retinal locus (PRL). Previous studies have examined adaptation to central vision loss with monocular 2D paradigms, whereas in real tasks, patients make binocular eye movements to targets of various sizes and depth in 3D environments. Methods: We therefore examined monocular and binocular contrast sensitivity functions with a 26-AFC (alternate forced choice) band-pass filtered letter identification task at 2° or 6° eccentricity in observers with simulated central vision loss. Binocular stimuli were presented in corresponding or non-corresponding stereo- scopic retinal locations. Gaze-contingent scotomas (0.5° radius disks of pink noise) were simulated independently in each eye with a 1000 Hz eye tracker and 120 Hz dichoptic shutter glasses. Results: Contrast sensitivity was higher for binocular than monocular conditions, but only exceeded probability summation at low-mid spatial frequencies in corresponding retinal locations. At high spatial frequencies or non-corresponding retinal locations, binocular contrast sensitivity showed evidence of interocular suppression. Conclusions: These results suggest that binocular vision deficits may be underestimated by monocular vision tests and identify a method that can be used to select a PRL based on binocular contrast summation. |
Robert G. Alexander; Gregory J. Zelinsky Occluded information is restored at preview but not during visual search Journal Article In: Journal of Vision, vol. 18, no. 11, pp. 1–16, 2018. @article{Alexander2018, Objects often appear with some amount of occlusion. We fill in missing information using local shape features even before attending to those objects—a process called amodal completion. Here we explore the possibility that knowledge about common realistic objects can be used to ‘‘restore'' missing information even in cases where amodal completion is not expected. We systematically varied whether visual search targets were occluded or not, both at preview and in search displays. Button-press responses were longest when the preview was unoccluded and the target was occluded in the search display. This pattern is consistent with a target-verification process that uses the features visible at preview but does not restore missing information in the search display. However, visual search guidance was weakest whenever the target was occluded in the search display, regardless of whether it was occluded at preview. This pattern suggests that information missing during the preview was restored and used to guide search, thereby resulting in a feature mismatch and poor guidance. If this process were preattentive, as with amodal completion, we should have found roughly equivalent search guidance across all conditions because the target would always be unoccluded or restored, resulting in no mismatch. We conclude that realistic objects are restored behind occluders during search target preview, even in situations not prone to amodal completion, and this restoration does not occur preattentively during search. |
Ken-ichi Amemori; Satoko Amemori; Daniel J. Gibson; Ann M. Graybiel Striatal microstimulation induces persistent and repetitive negative decision-making predicted by striatal beta-band oscillation Journal Article In: Neuron, vol. 99, no. 4, pp. 829–841.e6, 2018. @article{Amemori2018, Persistent thoughts inducing irrationally pessimistic and repetitive decisions are often symptoms of mood and anxiety disorders. Regional neural hyperactivities have been associated with these disorders, but it remains unclear whether there is a specific brain region causally involved in these persistent valuations. Here, we identified potential sources of such persistent states by microstimulating the striatum of macaques performing a task by which we could quantitatively estimate their subjective pessimistic states using their choices to accept or reject conflicting offers. We found that this microstimulation induced irrationally repetitive choices with negative evaluations. Local field potentials recorded in the same microstimulation sessions exhibited modulations of beta-band oscillatory activity that paralleled the persistent negative states influencing repetitive decisions. These findings demonstrate that local striatal zones can causally affect subjective states influencing persistent negative valuation and that abnormal beta-band oscillations can be associated with persistency in valuation accompanied by an anxiety-like state. Amemori et al. identified candidate subcortical loci potentially related to persistency of anxiety-like states and inflexibility in OCD. The authors' work in non-human primates shows that striatal stimulation induces repetitive negative choice pattern, accompanied by modulation of striatal beta oscillation. |
Brian A. Anderson; Haena Kim Mechanisms of value-learning in the guidance of spatial attention Journal Article In: Cognition, vol. 178, pp. 26–36, 2018. @article{Anderson2018, The role of associative reward learning in the guidance of feature-based attention is well established. The extent to which reward learning can modulate spatial attention has been much more controversial. At least one demonstration of a persistent spatial attention bias following space-based associative reward learning has been reported. At the same time, multiple other experiments have been published failing to demonstrate enduring attentional biases towards locations at which a target, if found, yields high reward. This is in spite of evidence that participants use reward structures to inform their decisions where to search, leading some to suggest that, unlike feature-based attention, spatial attention may be impervious to the influence of learning from reward structures. Here, we demonstrate a robust bias towards regions of a scene that participants were previously rewarded for selecting. This spatial bias relies on representations that are anchored to the configuration of objects within a scene. The observed bias appears to be driven specifically by reinforcement learning, and can be observed with equal strength following non-reward corrective feedback. The time course of the bias is consistent with a transient shift of attention, rather than a strategic search pattern, and is evident in eye movement patterns during free viewing. Taken together, our findings reconcile previously conflicting reports and offer an integrative account of how learning from feedback shapes the spatial attention system. |
Brian A. Anderson; Haena Kim On the representational nature of value-driven spatial attentional biases Journal Article In: Journal of Neurophysiology, vol. 120, no. 5, pp. 2654–2658, 2018. @article{Anderson2018a, Reward learning biases attention toward both reward-associated objects and reward-associated regions of space. The relationship between objects and space in the value-based control of attention, as well as the contextual specificity of space-reward pairings, remains unclear. In the present study, using a free-viewing task, we provide evidence of overt attentional biases toward previously rewarded regions of texture scenes that lack objects. When scrutinizing a texture scene, participants look more frequently toward, and spend a longer amount of time looking at, regions that they have repeatedly oriented to in the past as a result of performance feedback. These biases were scene specific, such that different spatial contexts produced different patterns of habitual spatial orienting. Our findings indicate that reinforcement learning can modify looking behavior via a representation that is purely spatial in nature in a context-specific manner. |
Eduardo A. Aponte; Dominic G. Tschan; Klaas E. Stephan; Jakob Heinzle Inhibition failures and late errors in the antisaccade task: Influence of cue delay Journal Article In: Journal of Neurophysiology, vol. 120, no. 6, pp. 3001–3016, 2018. @article{Aponte2018, In the antisaccade task participants are required to saccade in the opposite direction of a peripheral visual cue (PVC). This paradigm is often used to investigate inhibition of reflexive responses as well as voluntary response generation. However, it is not clear to what extent different versions of this task probe the same underlying processes. Here, we explored with the Stochastic Early Reaction, Inhibition, and late Action (SERIA) model how the delay between task cue and PVC affects reaction time (RT) and error rate (ER) when pro- and antisaccade trials are randomly interleaved. Specifically, we contrasted a condition in which the task cue was presented before the PVC with a condition in which the PVC served also as task cue. Summary statistics indicate that ERs and RTs are reduced and contextual effects largely removed when the task is signaled before the PVC appears. The SERIA model accounts for RT and ER in both conditions and better so than other candidate models. Modeling demonstrates that voluntary pro- and antisaccades are frequent in both conditions. Moreover, early task cue presentation results in better control of reflexive saccades, leading to fewer fast antisaccade errors and more rapid correct prosaccades. Finally, high-latency errors are shown to be prevalent in both conditions. In summary, SERIA provides an explanation for the differences in the delayed and nondelayed antisaccade task. |
Fabrice Arcizet; Richard J. Krauzlis Covert spatial selection in primate basal ganglia Journal Article In: PLoS Biology, vol. 16, no. 10, pp. e2005930, 2018. @article{Arcizet2018, The basal ganglia are important for action selection. They are also implicated in perceptual and cognitive functions that seem far removed from motor control. Here, we tested whether the role of the basal ganglia in selection extends to nonmotor aspects of behavior by recording neuronal activity in the caudate nucleus while animals performed a covert spatial attention task. We found that caudate neurons strongly select the spatial location of the relevant stimulus throughout the task even in the absence of any overt action. This spatially selective activity was dependent on task and visual conditions and could be dissociated from goal-directed actions. Caudate activity was also sufficient to correctly identify every epoch in the covert attention task. These results provide a novel perspective on mechanisms of attention by demonstrating that the basal ganglia are involved in spatial selection and tracking of behavioral states even in the absence of overt orienting movements. |
Scott P. Ardoin; Katherine S. Binder; Andrea M. Zawoyski; Tori E. Foster Examining the maintenance and generalization effects of repeated practice: A comparison of three interventions Journal Article In: Journal of School Psychology, vol. 68, pp. 1–18, 2018. @article{Ardoin2018, Repeated reading (RR) procedures are consistent with the procedures recommended by Haring and Eaton's (1978) Instructional Hierarchy (IH) for promoting students' fluent responding to newly learned stimuli. It is therefore not surprising that an extensive body of literature exists, which supports RR as an effective practice for promoting students' reading fluency of practiced passages. Less clear, however, is the extent to which RR helps students read the words practiced in an intervention passage when those same words are presented in a new passage. The current study employed randomized control design procedures to examine the maintenance and generalization effects of three interventions that were designed based upon Haring and Eaton's (1978) IH. Across four days, students either practiced reading (a) the same passage seven times (RR+RR), (b) one passage four times and three passages each once (RR+Guided Wide Reading [GWR]), or (c) seven passages each once (GWR+GWR). Students participated in the study across 2 weeks, with intervention being provided on a different passage set each week. All passages practiced within a week, regardless of condition, contained four target low frequency and four high frequency words. Across the 130 students for whom data were analyzed, results indicated that increased opportunities to practice words led to greater maintenance effects when passages were read seven days later but revealed minimal differences across conditions in students' reading of target words presented within a generalization passage. |
Wesley R. Barnhart; Samuel Rivera; Christopher W. Robinson Effects of linguistic labels on visual attention in children and young adults Journal Article In: Frontiers in Psychology, vol. 9, pp. 358, 2018. @article{Barnhart2018, Effects of linguistic labels on learning outcomes are well-established; however, developmental research examining possible mechanisms underlying these effects have provided mixed results. We used a novel paradigm where 8-year-olds and adults were simultaneously trained on three sparse categories (categories with many irrelevant or unique features and a single rule defining feature). Category members were either associated with the same label, different labels, or no labels (silent baseline). Similar to infant paradigms, participants passively viewed individual exemplars and we examined fixations to category relevant features across training. While it is well established that adults can optimize their attention in forced-choice categorization tasks without linguistic input, the present findings provide support for label induced attention optimization: simply hearing the same label associated with different exemplars was associated with increased attention to category relevant features over time, and participants continued to focus on these features on a subsequent recognition task. Participants also viewed images longer and made more fixations when images were paired with unique labels. These findings provide support for the claim that labels may facilitate categorization by directing attention to category relevant features. |