The video below is exactly what it looks like: a pulse of light is being delivered directly into the mouse’s brain — its motor cortex — and forcing it to turn left. When the light turns off, the mouse returns back to its normal behavior. You’ve now seen first-hand what the emerging branch of science, termed optogenetics, is capable of doing. Fittingly, brain science is undergoing a current revolution at, er, the speed of light. Bah dum tsh!