Dynamics of Suppression in Macaque Primary Visual Cortex

By Matthew A. Smith, Wyeth Bair, J. Anthony Movshon. 2006

121 citations recorded by the source corpus.

The response of a neuron in primary visual cortex (V1) to an optimal stimulus in its classical receptive field (CRF) can be reduced by the presence of an orthogonal mask, a phenomenon known as cross-orientation suppression. The presence of a parallel stimulus outside the CRF can have a similar effect, in this case known as surround suppression. We used a novel stimulus to probe the time course of cross-orientation suppression and found that it is very fast, starting even before the response to optimal excitatory stimuli. However, it occurs with some delay after the offset response, considered to be a measure of the earliest excitatory signals that reach the CRF. We also examined the time course of response to a stimulus presented outside the CRF and found that cross-orientation suppression begins substantially earlier than surround suppression measured in the same cells. Together, these findings suggest that cross-orientation suppression is attributable to either direct feedforward signal paths to V1 neurons or a circuit involving fast local interneurons within V1. Feedback from higher cortical areas is implicated in surround suppression, but our results make this an implausible mechanism for cross-orientation suppression. We conclude that suppression from inside and outside the CRF occur through different mechanisms.

Subfields: Cellular and Molecular Neuroscience, Cognitive Neuroscience

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Citations in the corpus

Temporal properties of surround suppression in cat primary visual cortex (2007, background): “…for orientation ~Blakemore & Tobin, 1972; DeAngelis et al., 1994; Sengpiel et al., 1997! and its onset is relatively slow ~Bair et al., 2003; Smith et al., 2006!. Surround suppression could be provided by a subclass of V1 neurons that respond to faster drift rates than the majority of…”
Inhibition, spike threshold, and stimulus selectivity in primary visual cortex. (2008, unknown): “Fourth, the onset of suppression is coincident with the onset of neuronal responses, leaving no time for the activation of the inhibitory circuits (Smith et al., 2006).”
Inhibitory Stabilization of the Cortical Network Underlies Visual Surround Suppression (2009, background): “Lateral inhibition may thus be implemented through a network mechanism that leads to a reduction in local recurrent excitation together with a paradoxical decrease in synaptic inhibition, rather than the expected increase in inhibition.”