Center-surround inhibition deepens binocular rivalry suppression

Area of Science:

• Neuroscience
• Visual Perception
• Computational Neuroscience

Background:

• Binocular rivalry occurs when dissimilar images are presented to each eye, causing perception to alternate.
• Stimuli near rival targets influence perceptual dominance duration.
• Surrounding motion stimuli can modulate rivalry, decreasing dominance of same-direction targets.

Purpose of the Study:

• To investigate how a drifting surround grating affects binocular rivalry suppression depth.
• To determine if surround motion direction modulates this suppression.
• To explore the neural basis of enhanced suppression, hypothesizing a role for area MT (V5).

Main Methods:

• Used a stationary concentric grating rivaling with a drifting grating.
• Measured suppression depth via sensitivity to a speed discrimination probe on the rival grating.
• Varied surround grating motion (same, opposed, static, orthogonal) and presentation (monocular, binocular, contralateral).

Main Results:

• A drifting surround grating significantly increased binocular rivalry suppression depth compared to no surround.
• Same-direction surround motion yielded the strongest suppression, followed by opposed motion.
• Monocular, binocular, and contralateral surrounds were effective; static and orthogonal surrounds were not.

Conclusions:

• Surround motion enhances binocular rivalry suppression, particularly with congruent motion direction.
• Results support the hypothesis that surround inhibition in higher-level visual areas, like MT (V5), contributes to rivalry suppression.
• This suggests a summation of rivalry suppression and surround inhibition deepens the suppression of unseen targets.