Exclusive functional subnetworks of intracortical projection neurons in primary visual cortex

Abstract

The rules by which neurons in neocortex choose their synaptic partners are not fully understood. In sensory cortex, intermingled neurons encode different attributes of sensory inputs and relay them to different long-range targets. While neurons with similar responses to sensory stimuli make connections preferentially, the relationship between synaptic connectivity within an area and long-range projection target remains unclear. We examined the local connectivity and visual responses of primary visual cortex neurons projecting to anterolateral (AL) and posteromedial (PM) higher visual areas in mice. Although the response properties of layer 2/3 neurons projecting to different targets were often similar, they avoided making connections with each other. Thus, projection target acts independently of response similarity to constrain local synaptic connectivity of cortical neurons. We propose that this segregated connectivity rule reduces the crosstalk between different populations of projection neurons, allowing top-down signal to modulate the activity of these output channels independently.