Control of response reliability by parvalbumin-expressing interneurons in visual cortex

Area of Science:

• Neuroscience
• Visual Cortex Function
• Neural Inhibition

Background:

• Visual cortical neurons exhibit reliable and sparse responses to natural stimuli.
• Inhibitory interneurons are essential for these response properties, but their specific roles remain unclear.

Purpose of the Study:

• To investigate the distinct contributions of parvalbumin (PV) and somatostatin (SOM) interneurons to visual cortical processing.
• To determine the role of PV and SOM interneurons in response reliability and stimulus discrimination.

Main Methods:

• Optogenetic suppression of PV- and SOM-expressing interneurons in the primary visual cortex of mice.
• Recording neural responses to natural stimuli in anaesthetized and awake conditions.
• Analysis of firing rates, signal-to-noise ratio (SNR), and neural discrimination performance.

Main Results:

• Optogenetic suppression of PV interneurons reduced response reliability and impaired neural discrimination of natural stimuli.
• PV suppression altered firing rates, increasing low rates and decreasing high rates, thus reducing SNR.
• Suppression of SOM interneurons increased overall firing rates but did not affect SNR or stimulus discrimination.

Conclusions:

• Parvalbumin (PV) interneurons play a critical role in ensuring the reliability of visual cortical representations.
• PV interneurons are essential for accurate neural discrimination of natural stimuli.
• Somatostatin (SOM) interneurons have a different, less direct role in visual cortical processing compared to PV interneurons.