Optogenetically Induced Spatiotemporal Gamma Oscillations in Visual Cortex

TL;DR

This study demonstrates that targeted optogenetic stimulation can induce sustained Gamma oscillations in the rat visual cortex, providing insights into their spatiotemporal dynamics and potential roles in cognition and neuropsychiatric disorders.

Contribution

It introduces a novel method of inducing and analyzing Gamma oscillations in vivo using optogenetics combined with computational modeling.

Findings

Optogenetic stimulation induces sustained Gamma oscillations in rat visual cortex.

Gamma waves exhibit specific spatiotemporal patterns during stimulation.

Computational analysis supports the experimental observations of Gamma dynamics.

Abstract

It has been hypothesized that Gamma cortical oscillations play important roles in numerous cognitive processes and may involve psychiatric conditions including anxiety, schizophrenia, and autism. Gamma rhythms are commonly observed in many brain regions during both waking and sleep states, yet their functions and mechanisms remain a matter of debate. Spatiotemporal Gamma oscillations can explain neuronal representation, computation, and the shaping of communication among cortical neurons, even neurological and neuropsychiatric disorders in neo-cortex. In this study, the neural network dynamics and spatiotemporal behavior in the cerebral cortex are examined during Gamma brain activity. We have directly observed the Gamma oscillations on visual processing as spatiotemporal waves induced by targeted optogenetics stimulation. We have experimentally demonstrated the constant optogenetics stimulation based on the ChR2 opsin under the control of the CaMKII{\alpha} promotor, which can induce sustained narrowband Gamma oscillations in the visual cortex of rats during their comatose states. The injections of the viral vector [LentiVirus CaMKII{\alpha} ChR2] was performed at two different depths, 200 and 500 \mu m. Finally, we computationally analyze our results via Wilson-Cowan model.