Investigating Saccade-Onset Locked EEG Signatures of Face Perception during Free-Viewing in a Naturalistic Virtual...

Area of Science:

• Cognitive Neuroscience
• Human-Computer Interaction
• Neuroimaging

Background:

• Investigating cognitive processes in naturalistic settings is crucial.
• Virtual reality (VR) and electroencephalography (EEG) offer combined naturalistic environments with experimental control.
• Technical challenges remain in analyzing continuous gaze data, particularly regarding event triggers.

Purpose of the Study:

• To determine if saccade onsets are a suitable replacement for fixation onsets in analyzing continuous gaze trajectories.
• To assess if VR can detect category-specific differences in stimuli based on saccade durations.
• To investigate face perception using VR, EEG, and eye-tracking in a naturalistic environment.

Main Methods:

• An immersive virtual reality (VR) study was conducted with free viewing and movement.
• Participants (14 males, 19 females) viewed houses, background stimuli, and static/moving pedestrians.
• Electroencephalography (EEG) and eye-tracking data were collected, with trials aligned to saccade onsets and fixation onsets.

Main Results:

• Aligning trials to saccade onsets yielded more defined electroencephalography (EEG) event-related potentials (ERPs), especially for the P100 component, compared to fixation onsets.
• Saccade-onset ERPs proved to be a more suitable analysis method for this VR experiment.
• Category-based differences (face vs. background) in saccade-onset ERPs were observed across a wide temporal window and multiple electrode sites.

Conclusions:

• Saccade onsets are a more effective trigger for event-related potential (ERP) analysis in immersive VR experiments than fixation onsets.
• The study validates the use of VR, EEG, and eye-tracking for studying cognitive processes in naturalistic settings.
• Findings enhance understanding of face perception and the utility of saccade-based event triggers in neuroscientific research.