Development and application of control tools for use in optogenetics research

Abstract

Optogenetic actuators such as Channelrhodopsin-2 (ChR2) are seven-transmembrane proteins that function as light-gated ion channels. These naturally occurring proteins are found in green algae and serve as sensory photoreceptors controlling phototaxis. Operationally, they contain the light-isomerizable chromophore all-trans-retinal that, upon absorption of a photon at or around 473nm, a conformational change to 13-cis-retinal is induced. This change opens the channel allowing cations to flow through. In the absence of light, the 13-cis-retinal relaxes back to the resting all-trans-retinal conformation and the channel closes. When an actuators packaged into a lox-containing Adeno-associated virus is used in conjunction with a mouse that expresses the Cre recombinase enzyme in a specific cell type, cell specific expression of the opsin is achieved. When used with LEDs, lasers, or specifically fabricated light delivery tools, control of very specific neural networks is realized. This thesis provides a review of optogenetics and details the development and application of a novel wireless device to optically control neural circuits and behavior.