Optogenetics

This November 21 2008 Google tech talk of Karl Deisseroth on optogenetics is quite stunning. The idea of optogenetics is to genetically alter specific types of neurons of alive and behaving subjects (currently rats) with genes coding for opto-sensitive ion-pumps (ion-pumps are small proteins or "bio-machines" which reside in the membrane of the cell and which pump certain ions for the cell's surrounding to the cell and dump other ions out of the cell). The genes that are added to these specific neuron-types, are taken from simple single cell algae and microbial life where they code for optically driven ion pumps used by these simple lifeforms to directly extract their life's energy from photons. These optically driven ion pumps are then artificially placed in specific neuron cells, which allows to optically excite or inhibit very specific brain regions by, thanks to the bacteria's ion pumps, effectively injecting an electrical current in these cells by simply shining light on them. This incredible techniques allows for an unprecedented precision in the external control of neurons in the brain. As an example they show a modified rodent which they can externally steer, by simple pulses of light (the controlled rat really desires to walk in leftward circles). But this toy example really pales when the true far-reaching consequences of this technique are understood: it introduces a whole new ballgame in how we can start studying the exact operation of the brain up to the tiniest details, and it can provide cures for diseases such as depression, epilepsy, Parkinson's and Alzheimer's disease. I started studying Deisseroth's papers today.