This is really cool: the lab of Karl Deisseroth have been using precisely targeted viruses to deliver genes into neurons in a rat’s brain. The gene in question encodes for a light sensitive ‘switch’ in the neurons. If you shine the right color of light onto it, the neuron will fire. They inserted these genes into neurons in the primary motor cortex of the rat. This is what happens when they shine the light (which we can also see):
It seems like something straight out of sci-fi! Apart from being flat out cool, these studies are also providing a lot of insight into how we can properly interpret findings from fMRI studies, which is a question that has been somewhat controversial in the last decade. I expect that this will be the first of many exciting discoveries as a result of this technique.
Read more about the new science of optogenetics at Neurotopia.