From initial formation to developmental refinement: GABAergic inputs shape neuronal subnetworks in the primary...

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Systems Neuroscience

Background:

• Neuronal subnetworks (ensembles) are crucial for information processing in the adult brain.
• Understanding their early formation is key to comprehending brain development.

Purpose of the Study:

• To investigate the establishment and maturation of neuronal subnetworks in the mouse primary somatosensory cortex (S1) during early postnatal development (P11-P21).
• To explore the role of gamma-aminobutyric acid (GABA)ergic activity in modulating subnetwork coherence during this critical period.

Main Methods:

• Utilized *in vivo* two-photon calcium imaging in mice.
• Analyzed neuronal activity patterns and employed clustering techniques to identify subnetworks.
• Manipulated GABAergic activity to assess its impact on subnetwork coherence.

Main Results:

• Neuronal activity transitioned from highly synchronized at P11 to sparser by P21.
• The number of subnetworks remained constant, but their activity patterns became more distinct and coherent.
• Increased GABAergic activity at P15/16 enhanced subnetwork coherence during maturation.

Conclusions:

• Neuronal subnetworks are established early in postnatal development in the S1 cortex.
• GABAergic inputs are critical modulators of developing S1 neuronal subnetworks.
• These findings provide insights into the developmental trajectory of functional neural circuits.