By Suzanne Rostler

NEW YORK (Reuters Health) - What do engineers use for birth control? Their personalities!

Whether you found this joke funny might reveal something about the way your brain works, according to researchers. Their study, which investigated how the human brain processes this joke and 29 others, identified a particular area of the brain that appears to be involved in your sense of humor.

In an interview with Reuters Health, lead author Dr. Vinod Goel said that this area is known as the medial ventral prefrontal cortex. Patients with damage to that region are sometimes ``emotionally flat and unresponsive,'' or in other words, they lack a sense of humor, he explained.

The study also revealed that ``getting'' or understanding a particular type of joke involves different brain areas. For example, understanding a joke that is based on a pun (Why did the golfer wear two sets of pants? He got a hole in one!) involves an area of the brain that is activated during speech production, while understanding a so-called semantic joke such as the one about the engineer, involves a region that is used to process language.

``However, the feeling of amusement or mirth associated with both types of jokes involves a common area,'' Goel said.

The findings are published in the March issue of Nature Neuroscience.

Goel and co-author, Dr. Raymond J. Dolan of the Institute of Neurology in London, UK, used functional MRI--a type of brain imaging technique--to monitor brain activity of 14 people as they listened to two types of jokes. The study participants then rated the jokes, which were either semantic or based on puns, on a ``funniness'' scale.

The investigators found that the greater the activity in the medial ventral prefrontal cortex, the funnier an individual rated a joke.

SOURCE: Nature Neuroscience 2001;4:237-238.SOURCE: Nature Neuroscience