Optogenetics is a biological technique that involves the use of light to control neurons that have been genetically modified to express light-sensitive ion channels. As such, optogenetics is a neuromodulation method that uses a combination of techniques from optics and genetics to control the activities of individual neurons in living tissue – even within freely-moving animals.

How to deliver light deep within the brain or other tissues has been a common problem. A light-guiding hydrogel-based implant may help solve this problem.

In some usages, optogenetics also refers to optical monitoring of neuronal activity or control of other biochemical pathways in non-neuronal cells, although these research activities preceded the use of light-sensitive ion channels in neurons.

As optogenetics is used by some authors to refer to only optical control of the activity of genetically defined neurons and not these additional research approaches, the term optogenetics is an example of polysemy.

Neuronal control is achieved using optogenetic actuators like channelrhodopsin, halorhodopsin, and archaerhodopsin, while optical recording of neuronal activities can be made with the help of optogenetic sensors for calcium (GCaMPs), vesicular release (synapto-pHluorin), neurotransmitters (GluSnFRs), or membrane voltage. Control (or recording) of activity is restricted to genetically defined neurons and performed in a spatiotemporal-specific manner by light.

 

Note:   The above text is excerpted from the Wikipedia article Optogenetics, which has been released under the GNU Free Documentation License.