Valentin Dragoi, The University of Texas Medical School at Houston

Population coding in visual cortical circuits

A fundamental property of cortical networks in the primary visual cortex (V1) of higher mammals is its functional organization, i.e., multiple stimulus dimensions are mapped such that neuronal response properties vary systematically across the cortical surface. Whether functional maps play any role in visual information processing and the pooling of signals relevant for perception is poorly understood. I will present recent results showing that optogenetic stimulation of distinct populations of excitatory neurons in V1 of macaque monkey can enhance the detection of an oriented stimulus when the stimulated population is tuned to the stimulus orientation. In contrast, activating populations of neurons untuned to the stimulus elicited a large increase in neuronal firing rates, but did not impact perception. By examining how optical stimulation influences the information encoded in population activity, we found that the light-induced improvement in behavioral performance was accompanied by a reduction in noise correlations and an increase in the population signal-to-noise ratio. These results demonstrate that causal manipulation of the responses of an informative population of excitatory neurons in V1 can bias the animal’s perceptual reports. We conclude that the functional architecture of V1 constrains the pooling of neural signals that influence perceptual decisions.

Organized by

Klaus Obermayer