Characterizing Mouse V1 Optogenetic-Mediated Rebound Effects
Date
2023-08-28
Authors
Shapiro, Jared
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Cortical circuits comprise excitatory pyramidal (Pyr) cells and inhibitory interneurons that work together to perform neural computations. Optogenetic studies in mouse primary visual cortex (V1) have focused on (i) sketching the connectivity between Pyr cells and distinct interneuron subtypes that express parvalbumin (Pvalb+), somatostatin (SOM+) and vasoactive intestinal peptide (VIP+), and (ii) examining how photostimulating these inhibitory interneuron subtypes shape Pyr cell receptive field properties. Rebound effects have been reported after the optogenetic light source is turned off, but no systematic analysis of rebounds has been performed. Here, we sought to characterize optogenetic-mediated rebound effects and investigate whether network features like V1 activity and connectivity can affect rebound magnitude.
Description
We leveraged optogenetics in mouse V1 to investigate whether network activity or connectivity affect post-photostimulation rebound effects in this circuit. We coupled differing levels of bottom-up visual stimulation of mouse V1 with photostimulation of Pvalb+, SOM+, or VIP+ interneurons separately to address these two questions. We collected data from 3 separate experiments using different visual stimuli and/or photostimulation protocols. We found converging evidence that coupling interneuron photostimulation with visual stimuli producing the strongest V1 responses also produced stronger rebound effects that were more prevalent across Pyr cell and interneuron populations. Importantly, Pyr cell and interneuron rebound effects differed in directionality and timing. We also report rebound effects were strongest and most prevalent when we coupled visual stimuli with Pvalb+ photostimulation rather than activating SOM+ or VIP+ interneurons. Overall, these results provide insight on experimental paradigms most conducive for producing optogenetic-mediated rebound effects in mouse V1, including coupling strong bottom-up visual stimulation with optogenetic activation of Pvalb+ cells in this circuit.
Keywords
Cortex, Visual Cortex, Optogenetics, Post-Inhibitory Rebound, Circuitry, Mouse