Changing microcircuits in the subplate of the developing cortex.

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cortical Development

Background:

• Subplate neurons (SPNs) are transient neurons vital for mammalian cerebral cortex maturation.
• SPNs are known to receive subcortical input and influence cortical activity via feedforward pathways.
• The intracortical feedback projections to SPNs remain largely uncharacterized.

Purpose of the Study:

• To investigate the spatial distribution of intracortical synaptic inputs onto SPNs in the developing mouse auditory cortex.
• To identify distinct classes of SPNs based on their input patterns.
• To understand the developmental emergence and circuit integration of these inputs.

Main Methods:

• In vitro photostimulation in mouse auditory cortex.
• Analysis of spatial distribution of synaptic inputs to SPNs.
• Classification of SPNs based on input layer patterns.

Main Results:

• SPNs were classified into two main groups based on distinct spatial input patterns.
• One class received inputs solely from deep cortical layers.
• The second class received inputs from both deep and superficial cortical layers, including layer 4, with superficial inputs emerging in the second postnatal week.

Conclusions:

• SPNs are integrated into both early feedforward and later feedback intracortical circuits.
• Distinct subplate circuits exist, with superficial inputs potentially modulating thalamic information.
• These findings highlight the dynamic role of SPNs in developing thalamocortical and intracortical networks.