Case pinpoints possible happiness center in brain

NEW YORK (Reuters Health)

Researchers found the tickle spot on one epileptic woman's brain when they realized that stimulating a specific brain region caused her to feel happy and laugh.

The finding strongly suggests that, at least in this woman, laughter and "mirth" are linked to this zone of the brain, the authors note.

The brain region, known as the inferior temporal gyrus, has also been linked to language and memory, study author Takeshi Satow, of the Kyoto University Graduate School of Medicine in Japan, told Reuters Health.

The researchers made their discovery in a 24-year-old woman who was about to undergo surgery to help control her epileptic seizures.

Before surgery, Satow and colleagues applied electric stimulation to the surface of her brain to determine the "functional areas" of that layer, which should be avoided during surgery.

When they applied a slight amount of stimulation for one second to the woman's inferior temporal gyrus, the patient reported feelings of "mirth." At the same time, she said a melody she remembered from childhood popped into her head.

The longer the investigators applied the stimulation, the longer she felt happy. And after five seconds of stimulation, she smiled.

The case report appears in the Journal of Neurology, Neurosurgery & Psychiatry.

Explaining why the childhood melody accompanied the woman's happy feelings, Satow speculated that stimulating that brain region simultaneously elicited pleasant memories -- in this case, a favored childhood song.

When the researchers applied stronger stimulation to the inferior temporal gyrus, the woman's feelings of happiness progressed to laughter. However, when the authors asked her to read sentences aloud while applying the stimulation, she did not laugh "because she paid strong attention to the task itself," Satow said.

Satow added that previous research has linked laughter to other regions of the brain, which suggests that applying stimulation to one region -- such as the inferior temporal gyrus -- ends up stimulating other brain sites as well.

"Several different (brain) areas can be responsible for mirth and laughter, independently," Satow said.