New study identifies brain circuits behind spontaneous and voluntary laughter

Laughter is a universal social signal that connects us with others, but the brain regions underlying laughter are not well understood, in part because it's hard to elicit genuine laughter in the lab.

In a review publishing on June 23 in the Cell Press journal Trends in Neurosciences, researchers analyze reports from medical procedures in which the brain is electrically stimulated in awake patients. Laughter can be an unintentional byproduct of these stimulations, allowing scientists to pinpoint laughter-evoking brain areas. By examining these reports and other clinical and animal studies, the authors describe two distinct networks in the brain for laughter: one that elicits spontaneous outbursts, and another that produces voluntary, conversational laughter.

Think about the last time you were laughing and you could not stop. Something set of you off and you are helpless with mirth."

That, she says, is spontaneous, involuntary, and sometimes uncontrollable laughter, which can be associated with certain types of seizure disorders, mood disorders, Alzheimer's disease, and schizophrenia.