Experience-dependent reorganization of inhibitory neuron synaptic connectivity

Area of Science:

• Neuroscience
• Olfactory System
• Synaptic Plasticity

Background:

• Organisms adapt perceptual systems to environmental stimuli.
• Understanding how experience reorganizes neural circuits is crucial for neuroscience.

Purpose of the Study:

• Investigate experience-dependent reorganization of synaptic connectivity in the mouse olfactory (piriform) cortex.
• Determine how odor exposure affects neuronal connectivity and information processing.

Main Methods:

• Developed an in vivo method using a deep convolutional network to identify monosynaptic connections from spike-time cross-correlograms.
• Analyzed 4.4 million single-unit pairs to map synaptic connectivity.
• Utilized computational modeling and physiological measurements to assess network properties.

Main Results:

• Excitatory piriform neurons with similar odor tuning show higher connectivity, unaffected by odor exposure.
• Experience alters inhibitory interneuron connectivity: differentially responding neurons form more connections.
• This reorganization depends solely on the inhibitory interneuron's tuning.
• Computational models predict and physiological data confirm increased response dimensionality and separability for familiar stimuli.

Conclusions:

• Non-Hebbian reorganization of inhibitory interneuron connectivity enhances discrimination of familiar environmental features.
• This synaptic plasticity mechanism selectively improves the processing of experienced stimuli.
• The findings offer insights into how the brain adapts to and discriminates sensory information.