HWNI, UC Berkeley
Long-range and local circuits for top-down modulation of visual cortical processing
Wednesday 08th of October 2014 at 12:00pm
Top-down modulation of sensory processing is a prominent cognitive process that allows
the animal to select sensory information most relevant to the current task, but the
underlying circuit mechanisms remain poorly understood. Here we show that a region of
mouse frontal cortex – the cingulate cortex (Cg) – can powerfully influence sensory
processing in the primary visual cortex (V1) through its long-range projection that
activates V1 local circuits containing specific subtypes of GABAergic interneurons.
Optogenetic activation of Cg neurons strongly enhanced V1 neuron responses and
improved the mouse’s performance of a visual discrimination task. Focal activation of Cg
axons in V1 caused a response increase at the activation site but decrease at nearby
locations. This center-surround modulation depended on local GABAergic interneurons,
with somatostatin-positive interneurons contributing preferentially to surround
suppression, and vasoactive intestinal peptide-positive interneurons contributing to center
facilitation. These findings reveal how long-range cortico-cortical projections act through
local microcircuits to exert spatially specific top-down modulation of sensory processing.
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