Sensory integration in mouse insular cortex reflects GABA circuit maturation

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Computational Neuroscience

Background:

• The insular cortex (IC) integrates sensory, emotional, and cognitive information for complex behaviors.
• The developmental mechanisms underlying the IC's integrative capacity are not well understood.

Purpose of the Study:

• To investigate the emergence of multisensory integration (MSI) in the IC across different mouse strains.
• To identify potential circuit-level deficits contributing to impaired MSI in models of neurodevelopmental disorders.

Main Methods:

• Comparative analysis of MSI in C57BL/6 and BTBR T+tf/J mice.
• Assessment of γ-aminobutyric acid (GABA)ergic circuits and synaptic pruning.
• Pharmacological intervention with diazepam during a critical developmental window.
• Evaluation of MSI in additional monogenic models (GAD65, Shank3, Mecp2 knockout).

Main Results:

• Adult BTBR mice, a model for idiopathic autism, showed impaired MSI compared to C57BL/6 mice.
• The MSI deficit in BTBR mice was linked to weakened GABA circuits and compromised cross-modal input pruning.
• Early diazepam treatment in BTBR mice rescued adult inhibition and MSI.
• Impaired MSI was also observed in GAD65, Shank3, and Mecp2 knockout mouse models, all exhibiting parvalbumin-circuit abnormalities.

Conclusions:

• Developmental deficits in GABAergic circuits and synaptic pruning impair multisensory integration in the insular cortex.
• Early-life intervention targeting inhibition can rescue adult integrative functions in specific neurodevelopmental models.
• These findings provide insights into neural circuit dysfunction relevant to autism and schizophrenia.