Physics

Control engineering

Neuroscience

Perception

Visual cortex

Feed forward

Biology

Sensory system

Engineering

Voltage

Paleontology

Receptive field

Psychology

Surround suppression

Visual perception

Primate

Context (archaeology)

Quantum mechanics

Optogenetics

Negative feedback

Nature Communications

Sensory information travels along feedforward connections through a hierarchy of cortical areas, which, in turn, send feedback connections to lower-order areas. Feedback has been implicated in attention, expectation, and sensory context, but the mechanisms underlying these diverse feedback functions are unknown. Using specific optogenetic inactivation of feedback connections from the secondary visual area (V2), we show how feedback affects neural responses in the primate primary visual cortex (V1). Reducing feedback activity increases V1 cells’ receptive field (RF) size, decreases their responses to stimuli confined to the RF, and increases their responses to stimuli extending into the proximal surround, therefore reducing surround suppression. Moreover, stronger reduction of V2 feedback activity leads to progressive increase in RF size and decrease in response amplitude, an effect predicted by a recurrent network model. Our results indicate that feedback modulates RF size, surround suppression and response amplitude, similar to the modulatory effects of visual spatial attention.

Top-down feedback controls spatial summation and response amplitude in primate visual cortex