Hierarchy in sensory processing reflected by innervation balance on cortical interneurons

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• Sensory processing relies on modulated neural circuits.
• Long-range inputs to cortical interneurons are crucial but their selectivity is unclear.
• Understanding interneuron connectivity is key to deciphering brain information flow.

Purpose of the Study:

• To investigate the selectivity of long-range inputs to different types of cortical interneurons.
• To map hierarchical connectivity in the visual processing pathway.
• To elucidate the role of interneuron-specific connectivity in brain function.

Main Methods:

• Rabies-virus tracing to map neuronal connections.
• Optogenetics-assisted recording for functional analysis.
• Algorithmic analysis of innervation weights to predict hierarchical positions.

Main Results:

• Hierarchical corticocortical and thalamocortical connectivity is reflected in input weights to parvalbumin-positive (PV+) and vasoactive intestinal peptide-positive (VIP+) neurons.
• Bottom-up inputs preferentially target PV+ neurons, while top-down inputs target VIP+ neurons.
• Developed algorithms accurately predicted the hierarchical position of brain areas based on interneuron innervation.

Conclusions:

• Preferential targeting of specific interneurons by long-range inputs is essential for hierarchical information processing.
• This selectivity provides a mechanism for context-dependent modulation of sensory information.
• Findings offer insights into the organizational principles of neural circuits in the brain.