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Optogenetics: A light switch for nerve cells

How cool would it be if we could switch living cells in our bodies on and off just like all our gadgets and appliances? Well, science has made it possible, thanks to all the researchers who thought of this ingenious idea and also made it work. The science of optogenetics uses ‘light’ to play around with and manipulate living cells in tissues, specifically the nerve cells aka neurons in our brains.

Brain, the most complex and spectacular of all organs houses billions of neurons of numerous types. They are connected in networks and communicate with each other via chemical and electrical signals. In order to better understand how our brains work and figure out what goes wrong in case of disorders, zooming in at the cellular level is essential. Optogenetics is one technique which enables that, bringing together the tools of optics and genetics.

A class of light-sensitive proteins called ‘opsins’ are found across the tree of life from microbes to vertebrates. One particular opsin, the ‘Channel rhodopsin’, found in the light-sensing algae Chlamydomonas, regulates the flow of charges across cell membranes when exposed to blue light. These proteins are more like the solar cells that convert light into electricity to charge a battery.  Neurons are essentially tiny electrical devices and the idea is to bring in these light-sensitive opsins into neurons and make the cells respond to light by controlling their electrical activity.

Neurons of our interest are made to express these proteins with the help of the molecular biologist’s toolkit, genetic engineering. Now the cells are ready to be controlled by light pulses. Switching a particular group of cells ‘on’ or ‘off’ in a network help us understand their function better. This revolutionary technique has already furthered our understanding of some important psychiatric diseases. Optogenetics is just getting better by the day as different types of opsins are being discovered and molecular engineering tools are being developed.