Optogenetics 2.0: Brain control goes wireless via light, sound, or a drug
What the scientists had was a lab version of The Dog That Didn’t Bark — or, if Sherlock Holmes were chronicling the experiment, The Mice That Didn’t Freeze.
One at a time, the 20 mice went into a little cage in a lab at Caltech and nosed around for three minutes, until a tone sounded — and the metal floor of the cage zapped them with a mild shock. Twice more — tone, zap; tone, zap — to teach each mouse that sound meant imminent pain. A day later, the mice proved themselves quick studies: When they heard the tone they froze, a classic fear response.
