Relating variability in scalp EEG to variability in cortical morphology

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Sara Chaparian¹ (sarach@yorku.ca), Jeff Schall, Peter J. Kohler; ¹York University

Electroencephalography (EEG) is a widely used brain imaging modality that makes it possible to measure brain signals with minimal cost and invasiveness. A fundamental limitation to the usefulness of EEG is the challenge of relating signals measured at the scalp to the underlying cortical generators. Here we use previously collected EEG that was acquired under a Steady-State Visual Evoked Potentials (SSVEP) paradigm as participants (n=13) were viewing a stimulus set of regular textures. These data were acquired on two separate sessions, and the experimental design makes it possible to separately measure early visual responses related to image-level changes in the stimulus and more higher-level responses driven by symmetries within textures. We see substantial variability among individuals in early and especially in higher-level responses which clearly exceeds the variability between sessions. Because the underlying set of cortical areas that respond to symmetry is well-documented, it is possible to model the cortical sources of both low-level and higher-level symmetry-driven responses in individual participants. We do this based on structural MRI data for each of our participants and aim to quantify the extent to which variability in underlying cortical morphology determine variability in low-level and higher-level responses measured at the scalp. Specifically, we test whether features such as size of visual regions of interest, cortical thickness, and orientation of cortical surface can effectively predict the strength of responses.

Topic Area: PERCEPTION & ACTION: Vision