Effects of binocular suppression on surround suppression

Area of Science:

• Neuroscience
• Visual Perception
• Computational Neuroscience

Background:

• Neuronal responses in the primary visual cortex (V1) are modulated by surrounding stimuli.
• Surround suppression, the inhibition by stimuli outside the classical receptive field (CRF), impacts visual perception, such as reducing the perceived contrast of central stimuli.
• Previous research suggests two distinct mechanisms (early and late) underlie surround suppression.

Purpose of the Study:

• To investigate the neural substrates of early and late surround suppression mechanisms.
• To determine the differential effects of rendering surround stimuli invisible on these two mechanisms.

Main Methods:

• Utilized binocular suppression to selectively mask surround stimuli, rendering them invisible to observers.
• Assessed the impact of this visual masking on the previously identified early and late mechanisms of surround suppression.

Main Results:

• The early mechanism of surround suppression remained unaffected by binocular suppression (i.e., surround stimuli remained effective even when invisible).
• The late mechanism of surround suppression was completely eliminated by binocular suppression (i.e., invisible surround stimuli no longer suppressed V1 responses).

Conclusions:

• The distinct sensitivities of the early and late mechanisms to binocular suppression indicate they originate from different neural substrates.
• This finding provides crucial insights into the neural basis of visual surround suppression and its influence on perception.