Use of channelrhodopsin for activation of CNS neurons.

Optogenetics-the use of optically activated proteins to control cell function-allows for control of neurons with an unprecedented degree of spatial, temporal, and neurochemical precision. Three protocols are presented in this unit describing the use of channelrhodopsin-2 (ChR2), a light-activated cation channel. These protocols emphasize practical issues of working with ChR2, including guidelines for selecting a gene delivery method, light source, and method of tissue implantation, as well as steps for fabricating fiber optic patch cables and chronic implantable optical fibers. The first protocol describes the use of ChR2 in electrophysiological recordings from brain slices. The second and third involve the use of ChR2 in vivo, with light delivered through chronic fiber implants or guide cannula.