Abstract:

PURPOSE: Binocular rivalry arises when incompatible images are presented one to each eye. If the two eyes’ con?icting information were invisible with identical perceptual interpretations, does rivalry competition still occur? The current study investigated whether binocular rivalry can be induced from con?icting but invisible spatial patterns.
METHODS & RESULTS: A chromatic grating counter-phase ?ickering at 30 Hz appeared uniform, but produced signi?cant TAE and orientation-selective adaptation. The invisible pattern also generated significant BOLD activities in the early visual cortex, with minimal response in the parietal and frontal cortical areas. A monocularly presented invisible chromatic grating, compared to perceptually matched uniform stimuli, enhanced the rivalry competition with a low contrast visible grating presented to the fellow eye. Furthermore, switching from a uniform ?eld to a perceptually matched invisible chromatic grating produced interocular suppression at about 200 ms following the onset of the invisible grating. Experiments using briefly presented monocular probes revealed evidence for sustained rivalry competition between two invisible gratings during continuous dichoptic presentations.
CONCLUSIONS: These findings indicate that even without visible interocular conflict, and with minimal engagement of fronto-parietal cortex and consciousness related top-down feedbacks, perceptually identical patterns with invisible con?ict features produce rivalry competition in the early visual cortex.

Key words: Binocular rivalry, Awareness, Visual Cortex