State-Dependent Regulation of Cortical Processing Speed via Gain Modulation

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Animals require behavioral flexibility to adapt to dynamic environments and internal states.
• Top-down projections and neuromodulatory pathways are implicated in contextual modulation of sensory processing.
• The computational mechanisms underlying these top-down effects on cortical information processing speed remain largely unknown.

Purpose of the Study:

• To develop a theoretical framework for classifying the impact of cell type-specific top-down perturbations on cortical circuit information processing speed.
• To elucidate the role of intrinsic gain modulation in controlling neural circuit dynamics and stimulus processing.
• To link circuit connectivity, dynamics, and information processing through gain modulation.

Main Methods:

• Introduction of a theoretical framework to predict perturbation effects on stimulus processing via intrinsic gain modulation.
• Testing model predictions using large-scale electrophysiological recordings in the visual hierarchy of freely running mice.
• Analysis of single-cell intrinsic gain changes during locomotion and their effect on visual processing speed.

Main Results:

• The theoretical framework demonstrates that intrinsic gain modulation predicts perturbation effects on stimulus processing speed.
• Model predictions include counterintuitive outcomes, such as performance enhancement with increased input variance.
• Electrophysiological recordings in mice showed that decreased single-cell intrinsic gain during locomotion accelerated visual processing.

Conclusions:

• A novel theory of cell type-specific perturbations is established, applicable to top-down modulation and experimental manipulations (optogenetics, pharmacology).
• The theory establishes a link between circuit connectivity, neural dynamics, and information processing speed mediated by gain modulation.
• Findings highlight the role of intrinsic gain modulation in adapting neural circuit speed to behavioral context and internal states.