You may not need a sophisticated medical device to find your funny bone, but researchers have used MRI scans to identify portions of the brain that appreciate humour.
Our ability to comprehend a joke seems to be concentrated in the lower frontal lobes of the brain, which may explain why people who have suffered strokes to that part of the brain often have drastic changes to their personality, including a loss of sense of humour.
"There have been few studies of humour's place in the brain, but understanding the basis of positive emotions will likely be as helpful as understanding the negative ones," said Dr. Dean Shibata, assistant professor of radiology at the University of Rochester School of Medicine in New York. He presented results of the study yesterday at a meeting of the Radiological Society of North America in Chicago.
Functional magnetic resonance imaging (MRI) scans were done on 13 people in a series of tests that considered different aspects of humour.
Dr. Shibata and his colleagues found that just joining in the laughter activated a motor-control area near the top of the brain that is normally associated with planning movement and initiating speech.
But when the people viewed the written jokes and cartoons, activity was most prominent in the frontal lobe.
"As with almost any behaviour, we found that laughing at a joke involves several parts of the brain," Dr. Shibata said.
The frontal lobes were once regarded by as non-essential to daily function, leading to the treatment of many psychiatric disorders with frontal lobotomies earlier this century. Scientists now know that those regions are responsible for much of our complex social and emotional behaviour.