Investigating Evoked EEG Responses to Targets Presented in Virtual Reality

Area of Science:

• Neuroscience
• Virtual Reality Research
• Cognitive Science

Background:

• Virtual reality (VR) enables studying brain function in realistic settings.
• Analyzing neural responses in VR is complex due to high degrees of freedom.
• Traditional lab paradigms lack the ecological validity of VR.

Purpose of the Study:

• To investigate how electroencephalogram (EEG) data, specifically the P300 evoked response, is affected by different event-locking methods in VR.
• To analyze the latency and waveform shape of P300 responses when EEG is locked to target onset, saccade intersection, or first fixation.
• To assess the impact of these locking strategies on the discriminability of single-trial evoked responses.

Main Methods:

• A target detection task was designed within a 3D maze in VR.
• Target visual angle was varied as participants navigated the maze.
• EEG data was analyzed using three different event-locking approaches: target image onset, target-saccade intersection, and first fixation.

Main Results:

• Evoked response timing systematically shifted based on the chosen locking method.
• Differences in P300 waveform shape were observed across the different locking strategies.
• Single-trial analysis revealed that peak discriminability was similar for image- and saccade-locked data but decreased significantly for fixation-locked data.

Conclusions:

• The findings indicate a temporal and spatial spread in visual information perception within VR environments.
• The choice of event-locking strategy significantly influences the analysis of evoked neural responses in VR.
• Results highlight the need to adapt traditional analysis methods for complex, naturalistic VR paradigms to accurately capture neural processing.