Neocortical inhibitory imbalance predicts successful sensory detection

Area of Science:

• Neuroscience
• Computational Neuroscience

Background:

• Fast-spiking, parvalbumin-positive interneurons (FS/PVs) are critical for perceptual processing.
• Competing theories exist regarding the role of FS/PV dynamics in pyramidal (PYR) neuron firing rates and correlations.

Purpose of the Study:

• To investigate the dynamics of FS/PVs and PYR neurons during perceptual threshold detection.
• To reconcile opposing theories on optimal neural firing rates and correlations.

Main Methods:

• Population calcium imaging of FS/PVs and PYR neurons in somatosensory and visual neocortex.
• Computational modeling to simulate neural network dynamics.

Main Results:

• A subset of PYR neurons increased firing rate and correlations during successful detection ('hits').
• FS/PV populations predicted hits via either rate increases or decreases.
• Computational models demonstrated that inhibitory imbalance explains observed PYR activity patterns.

Conclusions:

• Transient inhibitory imbalance, driven by FS/PV interactions, is key to selecting informative PYR ensembles.
• This mechanism represents a common motif for optimal neocortical processing.
• FS/PVs differentially modulate PYR activity to facilitate accurate perception.