Binocular Inhibition: Using MEG and EEG to measure Binocular Integration in the Occipital Cortex

Abstract

Purpose: To determine if Binocular Inhibition and Binocular Summation are measurable using MEG, and explore their origins in the brain.

Methods: Binocular Inhibition was induced in 8 normal, healthy subjects using a neutral density filter in front of one eye. Visual evoked field Magnetoencephalography recordings were compared to visual evoked potential Electroencephalography recordings. Dynamic statistical parametric maps were generated to map brain activity under different viewing conditions.

Results: Binocular inhibition was measured at the occipital pole in both EEG and MEG using pattern reversal checkerboard stimuli for early components, MEG is less sensitive to late components. Flash stimuli did not induce binocular inhibition in either EEG or MEG sensors. The distribution of activity between binocular inhibition and binocular summation suggests that these are independent processes. Source estimation techniques produced limited interpretation for contributions of brain areas for inhibitory mechanisms but are able to capture generalized distributions in visual cortices.