Developmental neuronal origin regulates neocortical map formation

Sensory neurons in the neocortex exhibit distinct functional selectivity to constitute the neural map. While neocortical map of the visual cortex in higher mammals is clustered, it displays a striking salt-and-pepperpattern in rodents. However, little is known about the origin and basis of the interspersed neocortical map. Here we report that the intricate excitatory neuronal kinship-dependent synaptic connectivity influences pre-cise functional map organization in the mouse primary visual cortex. While sister neurons originating from the same neurogenic radial glial progenitors (RGPs) preferentially develop synapses, cousin neurons derived from amplifying RGPs selectively antagonize horizontal synapse formation. Accordantly, cousin neurons in similar layers exhibit clear functional selectivity differences, contributing to a salt-and-pepper architecture. Removal of clustered protocadherins (cPCDHs), the largest subgroup of the diverse cadherin superfamily, eliminates functional selectivity differences between cousin neurons and alters neocortical map organiza-tion. These results suggest that developmental neuronal origin regulates neocortical map formation via cPCDHs.

Automated summary

Sensory neurons in the neocortex play a key role in forming the neural map. The neocortical map of the visual cortex in rodents has a salt-and-pepper pattern, while in higher mammals it is clustered. This study reveals that synaptic connectivity among excitatory neurons, dependent on their kinship, influences the organization of the functional map in the mouse primary visual cortex. The removal of clustered protocadherins disrupts functional selectivity differences between neurons and alters neocortical map organization.