Developmental neuronal origin regulates neocortical map formation.

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• Neocortical maps in rodents display a "salt-and-pepper" pattern, unlike the clustered maps in higher mammals.
• The developmental origins and mechanisms underlying this interspersed neocortical map remain largely unknown.

Purpose of the Study:

• To investigate the role of neuronal kinship and synaptic connectivity in organizing the functional map of the mouse primary visual cortex.
• To elucidate the molecular mechanisms, specifically clustered protocadherins (cPCDHs), involved in this process.

Main Methods:

• Studied synaptic connectivity between sister and cousin neurons derived from radial glial progenitors (RGPs).
• Examined functional selectivity differences in neurons within similar cortical layers.
• Investigated the effects of removing clustered protocadherins (cPCDHs) on neuronal connectivity and map organization.

Main Results:

• Sister neurons preferentially form synapses, while cousin neurons selectively inhibit horizontal synapse formation.
• Cousin neurons exhibit distinct functional selectivity, contributing to the salt-and-pepper architecture.
• Deletion of cPCDHs abolishes functional selectivity differences between cousin neurons and disrupts neocortical map organization.

Conclusions:

• Developmental neuronal origin and kinship-dependent synaptic connectivity are critical for precise functional map formation in the neocortex.
• Clustered protocadherins (cPCDHs) play a key role in regulating neuronal functional selectivity and neocortical map organization.