Reduced inhibition in depression impairs stimulus processing in human cortical microcircuits

Area of Science:

• Neuroscience
• Computational Biology
• Psychiatry

Background:

• Cortical processing relies on balanced excitatory and inhibitory neural connections.
• Major depressive disorder (MDD) is linked to reduced inhibition, particularly involving somatostatin interneurons.
• The mechanistic link between reduced inhibition and cognitive deficits in human MDD requires further elucidation.

Purpose of the Study:

• To investigate the impact of reduced somatostatin interneuron-mediated inhibition on human cortical microcircuit processing.
• To establish mechanistic, quantitative links between altered inhibition and cognitive deficits in MDD.

Main Methods:

• Developed data-driven computational models of human cortical microcircuits.
• Integrated human cellular, circuit, and gene expression data for health and MDD models.
• Simulated microcircuit baseline and response activity to assess processing efficiency.

Main Results:

• Models showed reduced signal-to-noise ratio in MDD due to higher baseline activity.
• Increased false/failed stimulus detection was observed in the MDD models.
• Demonstrated mechanistically how reduced inhibition impairs cortical processing in depression.

Conclusions:

• Reduced somatostatin interneuron inhibition is a key factor in impaired cortical processing in MDD.
• Computational modeling provides quantitative insights into the neural basis of cognitive deficits in depression.
• Findings highlight the role of inhibitory circuit dysfunction in MDD pathophysiology.