PRIMARY VISUAL CORTEX MERGES SELECTIVE THALAMOCORTICAL AND LESS SELECTIVE INTRACORTICAL INPUTS FOR MOVEMENT AND VISION

Dynamics of cortical activity are thought to underlie various forms of cognitive computation, yet their origins remain elusive. In particular, it is unclear whether transient elevations of cortical firing during active movement periods arise directly from enhanced sensory inputs via the thalamus, from other cortical origins, or from other sources. Here, using tangential insertions of high-density electrodes in the primary visual cortex (V1) of mice, we strengthen previous observations that across the thalamus and the visual cortex, there are increases of neuronal activity concomitant to running, active facial movements, and visual stimulation. In addition, using such techniques, we measured simultaneously thalamocortical and intracortical functional synaptic connections, meanwhile monitoring movements and vision. Surprisingly, in these two excitatory synaptic contacts, efficacy is higher in intracortical connections than in thalamocortical connections. In contrast, contribution and mutual information are higher in thalamocortical than intracortical connections. In addition, using generalized linear models, we estimated the regression coefficients between movement and vision periods in both pre- and postsynaptic partners. These revealed a stronger transmission of both movements and vision in thalamocortical compared to intracortical connections, as illustrated by the higher correlation of their pre- to postsynaptic regression coefficients. Consequently, thalamocortical synapses appear to transmit more of both movement and visual information compared to intracortical connections. This raises the question of whether the lower-selectivity/higher-efficacy of intracortical inputs thereby permits more flexible computational capabilities from the cortex, across varying movement and vision related activity levels.