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Getting Started with NBS Presentation
Sam
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#1
08-27-2020, 15:59 PM (This post was last modified: 09-23-2025, 20:32 PM by Dan.)
The EyeLink API can be accessed within the Neurobehavioral Systems Presentation (NBS) Presentation programming environment via the PresLink extension. PresLink uses Presentation’s native eye tracker extension capabilities to allow full interaction with EyeLink systems.

Key functionalities include:
  • Sending commands to configure and control the eye tracker.
  • Sending event-marking messages to the EyeLink data file (EDF) to log the timing of critical experimental events.
  • Accessing eye-tracking data in real-time (e.g., for gaze-contingent experimental designs).
  • Sending special messages to EyeLink Data Viewer, including trial variables, stimulus information, and more.
The use of both PresLink and the EyeLink Developers Kit is completely license-free.


Installation Instructions:
To set up EyeLink integration with NBS Presentation, please follow these steps:
  1. Configure your Display PC's network connection to communicate with the EyeLink Host PC.
  2. Install the latest version of Presentation.
  3. Install the latest version of the EyeLink Developers Kit for Windows.
  4. Register the PresLink Extension within Presentation:
    1. Launch the Presentation software.
    2. Navigate to the Tools > Extension Manager.
    3. Click the Select Extension File button.
    4. Browse to the following directory and select the PresLink.DLL file:

    5. In the Register As field, type PresLink.
    6. Click Register Extension to complete the process.
       


Testing your installation:
After registering the PresLink extension, you should test it to verify that Presentation can communicate with the EyeLink Host PC.
  1. Open the Extension Manager by navigating to Tools > Extension Manager.
  2. In the Registered Extensions list, select PresLink.
  3. Click the Test Extension button.
       
  4. In the Eye Tracker Extension Test dialog that appears, click the main Start button in the top-left corner.
  5. Next, test the individual components by clicking the Start buttons for the Tracking, Recording, and Data sections.
       

    If these actions complete without error, the connection is working correctly.

PresLink Templates/Example Projects:
The EyeLink Developers Kit for Windows includes example scripts that demonstrate how to integrate the EyeLink system with NBS Presentation.

After installing the Developers Kit, you can find the projects in the following location:
  • Windows Start Menu > All Programs > SR Research > EyeLink Sample Experiments > NBS Presentation

    Note on PCL: All calls to the EyeLink API must be made using Presentation's scripting language, PCL (Presentation Control Language). This can be done within the PCL section of your Scenario (.sce) file or from a separate .pcl file, as shown in the examples.
Description of Examples
A contents.sce file within the folder provides a detailed description of each demo. A summary is provided below.

 
Templates Descriptions
SimplePicture A basic demo that records eye movements while an image is presented. It illustrates the standard messages for integration with EyeLink Data Viewer.
SimpleVideo A simple video demo that records eye movements while a video is presented. It includes animated targets for calibration and drift correction.
Pursuit A smooth pursuit demo that records eye movements while a target moves sinusoidally. It also shows how to log dynamic interest area information for playback in Data Viewer.
MRIDemo An example illustrating an fMRI block design. It demonstrates continuous recording and how to synchronize trials with a scanner trigger (the 't' key).
FixWindowFastSamples A gaze-contingent demo where a trial begins only after gaze is held within a central window for 500 ms, demonstrating real-time sample access.
GCFastSamples A gaze-contingent demo where a dot overlaid on an image is updated in real-time based on the latest gaze sample.
GCLinkEvents A gaze-contingent demo where a dot's location is updated based on the end coordinates of each detected saccade event.


Experiment Walkthrough
The NBS Presentation examples folder also contains a PDF document, Getting Started With Presentation And PresLink, which provides a detailed walkthrough of the SimplePicture experiment.

Integrating with EyeLink Data Viewer
It is a best practice to send special messages to the EyeLink data file (EDF) to enable seamless integration with EyeLink Data Viewer. All of the examples demonstrate how to log important information like trial start/end times, variables, and stimulus details.

For more information on the messaging protocol, please refer to these resources:

Documentation:
Further documentation can be found in the following locations:
  • For Presentation's general eye tracker functions, see the Presentation User Manual (Help > Presentation Documentation, under the “Eye Tracker Extension” section).
  • For specific PresLink commands, see the PresLink User Manual (accessible from the SR Research folder in the Windows Start Menu).
  • For a detailed walkthrough of the SimplePicture example, see the Getting Started With Presentation And PresLink.pdf document, located in the NBS Presentation examples folder.