Alien limb syndrome isn’t as extraterrestrial as it sounds—but it’s still pretty freaky. Patients complain that one of their hands has gone “rogue,” reaching for things without their knowledge.

“They sit on their hand trying to get it not to move,” says Ryan Darby, a neurologist and neuroscientist at Vanderbilt University in Nashville. “They’re not crazy. They know there’s not something controlling their arm, that it’s not possessed. But they really feel like they don’t have control.”

Now, a study analyzing the locations of brain lesions in these patients—and those who have akinetic mutism, in which people can scratch an itch and chew food placed into their mouths without being aware they’ve initiated these movements—are shedding light on how our brains know what’s going on with our bodies.

(continue reading)

Icon-O