December 4, 2003 - Nature

Humor tickles drug centre that gives hedonistic high. There's truth in the maxim 'laughter is a drug'. A comic cartoon fired up the same brain centre as a shot of cocaine, researchers are reporting.

A team at Stanford University in California asked lab mates, spouses and friends to select the wittiest newspaper cartoons from a portfolio. They showed the winning array to 16 volunteers while peering inside their heads by functional magnetic resonance imaging (fMRI).

The cartoons activated the same reward circuits in the brain that are tickled by cocaine, money or a pretty face, the neuroscientists found1. One brain region in particular, the nucleus accumbens, lit up seconds after a rib-tickler but remained listless after a lacklustre cartoon.

The nucleus accumbens is awash with the feelgood chemical dopamine. The region's buzz may explain the euphoria that follows a good joke, the team suggests. "Intuitively, it makes sense," agrees Bill Kelley, who studies humour at Dartmouth College in Hanover, New Hampshire.

Earlier investigations found that humour triggers brain regions that work out a joke's language and meaning, or those that control smiling and laughter. Kelley, for example, has studied people's brains while they watched episodes of television comedies Seinfeld and The Simpsons. "It's surprising it's not consistent," he says.

A powerful fMRI machine and a particularly detailed analysis may explain why the new study picked up activity in the reward areas as well, suggests lead researcher Allan Reiss.

Reiss hopes that the finding could help to diagnose the early stages of depression - or show whether antidepressants are taking effect - during which people's appreciation of humour is altered. "That would be a terrific way to use this type of work," he says.