The winners of the Nobel in Physiology or Medicine have been announced: it’s Karl Deisseroth, Georg Nagel and Peter Hegemann, for their work in optogenetics.

Back in my day, we’d have to pull a fine glass electrode and jab it into a cell to put an electrical current in it, and see what twitched or secreted or changed gene expression in response. It was admittedly a bit clumsy and had side effects: most of the cells I stabbed would die in response. Optogenetics lets a researcher modify the genetics of precursor cells so that they would produce a novel channel, a light sensitive rhodopsin derived from algae, that lurked in the membrane, and would only open when a light was shone on it. Instead of a needle, you could aim a laser at the cell, and trigger a current across the membrane non-invasively.

It’s a neat trick. You can have a whole nervous system laid out on your microscope, loaded with inherited copies of this rhodopsin, and cruise around zapping cells with a beam of light, and see what happens when those cells are stimulated. Or put a fiber optic in a brain and switch on neurons with a pulse of light. There are so many fun things to do!