Activation of specific interneurons improves V1 feature selectivity and visual perception.

Area of Science:

• Neuroscience
• Visual Processing
• Cellular Electrophysiology

Background:

• Cortical inhibitory interneurons, particularly GABAergic subtypes, are crucial for neural circuit function.
• The precise contribution of distinct interneuron subtypes to sensory processing remains incompletely understood.
• Parvalbumin-positive (PV+) interneurons are a major subtype in the neocortex, but their specific role in visual information processing requires elucidation.

Purpose of the Study:

• To investigate the causal role of parvalbumin-positive (PV+) interneuron activity in modulating neural selectivity and perceptual performance in the primary visual cortex (V1).
• To determine if enhancing PV+ interneuron activity can improve visual feature discrimination.

Main Methods:

• Utilized optogenetic techniques, including channelrhodopsin-2 (ChR2) for activation and archaerhodopsin-3 (Arch) for silencing, in the mouse V1.
• Employed multichannel silicon probe recordings to assess neuronal activity and feature selectivity (orientation tuning, direction selectivity).
• Compared the effects of activating PV+ interneurons versus silencing excitatory neurons and activating other interneuron subtypes (somatostatin, Vasoactive Intestinal Peptide).

Main Results:

• Optogenetic activation of PV+ interneurons significantly sharpened orientation tuning and enhanced direction selectivity of nearby V1 neurons.
• These effects were specifically attributed to PV+ interneuron activation, as silencing excitatory neurons or activating other interneuron subtypes did not yield similar improvements.
• PV+ interneuron activation in awake mice led to a significant improvement in orientation discrimination performance, correlating with enhanced V1 orientation tuning.

Conclusions:

• Increased spiking activity of PV+ interneurons causally enhances visual feature selectivity in the primary visual cortex.
• This enhancement of neural coding by PV+ interneurons directly translates to improved perceptual discrimination in mice.
• Provides the first evidence that specific cortical inhibitory interneuron subtypes can directly improve visual processing and perception.