The mind, said Raquel Welch, is an erogenous zone. And it is the brain, and how it organizes our erogenous zones, that has intrigued scientists for decades. Why is a nuzzled neck sexy when few would be turned on by a nuzzled nose? And why do men seem to have fewer erogenous zones than women? A new study has measured just how erotic our body bits are — and there are a few surprises for neuroscientists.