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Optogenetic Activation of Interneuron Subtypes Modulates Visual Contrast Responses of Mouse V1 Neurons
Jared T Shapiro1, Nicole M Michaud1, Jillian L King1
1Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
Cerebral Cortex (New York, N.Y. : 1991)
|August 19, 2021
Summary
Optogenetic activation of different cortical interneuron subtypes (parvalbumin+, somatostatin+, vasoactive intestinal peptide+) in mouse V1 revealed distinct effects on neural contrast tuning, varying with cortical depth.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Cortical Circuitry
Background:
- Interneurons are crucial for cortical information processing.
- Previous in vitro and in vivo studies suggest distinct roles for parvalbumin (Pvalb+), somatostatin (SOM+), and vasoactive intestinal peptide (VIP+) interneurons in the primary visual cortex (V1).
- Discrepancies exist regarding the in vivo computational roles of these interneuron subtypes during orientation tuning tasks.
Purpose of the Study:
- To elucidate the differential effects of optogenetically activating Pvalb+, SOM+, and VIP+ interneurons on the contrast tuning of V1 neurons.
- To investigate the influence of cortical depth and photostimulation intensity on these interneuron-mediated effects.
Main Methods:
- Optogenetic stimulation of Pvalb+, SOM+, and VIP+ interneurons in the mouse primary visual cortex (V1).
- Measurement of contrast tuning properties of V1 neurons under varying photostimulation conditions and cortical depths.
- Utilizing a conductance-based model to interpret pyramidal cell modulation based on interneuron photostimulation effects.
Main Results:
- Optogenetic illumination of the cortical surface induced similar saturating additive photostimulation effects across all three interneuron subtypes.
- These photostimulation effects demonstrated a dependency on cortical depth, particularly for Pvalb+ and SOM+ cells, rather than light intensity.
- A conductance-based model successfully explained pyramidal cell modulation by incorporating the observed interneuron photostimulation effects.
Conclusions:
- Cortical depth is a key factor modulating the impact of optogenetic stimulation on Pvalb+ and SOM+ interneurons.
- The study provides a refined understanding of interneuron subtype function in V1 contrast processing.
- Computational models incorporating these depth-dependent effects can accurately predict pyramidal cell responses.
