An Accumulating Neural Signal Underlying Binocular Rivalry Dynamics.

Area of Science:

• Neuroscience
• Visual Perception
• Cognitive Science

Background:

• Binocular rivalry involves alternating perception between conflicting images presented to each eye.
• Models suggest gradual changes in neural signals trigger perceptual alternations, but direct evidence was lacking.

Purpose of the Study:

• To identify and characterize physiological neural signals in the human visual cortex during binocular rivalry.
• To test whether these signals exhibit properties predicted by computational models of rivalry.

Main Methods:

• Measured steady-state visual evoked potentials (SSVEPs) using EEG in 84 participants viewing flickering gratings.
• Correlated SSVEP amplitude changes with reported percept durations during binocular rivalry.

Main Results:

• SSVEP amplitudes corresponding to suppressed stimuli increased, while those for dominant stimuli decreased, throughout each percept.
• Longer percept durations correlated with slower signal changes, consistent with gradual accumulation models.
• Rapid signal changes at percept end suggested transitions.

Conclusions:

• Identified human visual cortex signals exhibiting gradual dynamics consistent with neural models of binocular rivalry.
• Provides the first physiological evidence supporting threshold-based models of perceptual switching.
• Opens avenues for testing models of rivalry, bistable perception, and neural suppression.