Humor and the Brain

Humor plays a powerful and unique role in human life with wide-ranging effects on many aspects of functioning. Humor can tie people together, help us cope with daily stress, and have a positive effect on the immune systems. Hopefully, uncovering the brain's specific response to positive stimuli like humor and laughter may lead to new therapies for depression.

Laughter is a complex human behavior that occurs unconsciously. While we can consciously inhibit it, we don't consciously produce laughter. That is why it is very hard to laugh on command or to fake laughter. We know that many sensations and thoughts trigger laughter, and that it activates many parts of the body. While we know that certain parts of the brain are responsible for certain functions and tasks, it seems that laughter cannot be traced to one specific area of the brain. Furthermore the relation between laughter and humor is not understood, despite their evident connection.

Researchers believe we process humor and laughter through a complex pathway of brain activity that encompasses three main brain components. In one new study, researchers used imaging equipment to photograph the brain activity of healthy volunteers while they underwent a sidesplitting assignment of reading written jokes, viewing cartoons from The New Yorker magazine as well as "The Far Side" and listening to digital recordings of laughter. Preliminary results indicate that the humor-processing pathway includes parts of the frontal lobe brain area, important for cognitive processing; the supplementary motor area, important for movement; and the nucleus accumbens, associated with pleasure. Investigations support the notion that parts of the frontal lobe are involved in humor. Subjects' brains were imaged while they listened to jokes. An area of the frontal lobe was activated only when they thought a joke was funny. A study that compared healthy individuals with people who had damage to their frontal lobes, the subjects with the damaged frontal lobes were more likely to choose a wrong punch line to written jokes and didn't laugh or smile as much at funny cartoons or jokes.

Even though we may know more about what parts of the brain are responsible for humor, it is still hard to explain why we don't laugh or giggle when we tickle ourselves. Some scientists believe that laughing caused by tickling is a built-in reflex because even babies do it. If we tickle ourselves in the same spot our friend tickled us, we do not laugh as we did previously. The information sent to your spinal cord and brain should be exactly the same. Apparently for tickling to work, the brain needs tension and surprise. When you tickle yourself, you know exactly what will happen...there is no tension or surprise. How the brain uses this information about tension and surprise is still a mystery, but there is some evidence that the cerebellum may be involved. Because one part of the brain tells another: "It's just you. Don't get excited". Investigations suggest that during self-tickling, the cerebellum tells an area called the somato -sensory cortex what sensation to expect, and that this dampens the tickling sensation. It looks as if the killjoy is found in the cerebellum

Dr. Shibata of the University of Rochester School of Medicine said our neurons get tickled when we hear a joke. The brain's 'funny bone' is located at the right frontal lobe just above the right eye and appears critical to our ability to recognize a joke. Dr. Shibata gave his patients MRI scans to measure brain activity. Dr. Shibata tried to find out what part of the brain is particularly active while telling the punch line of a joke as opposed to the rest of the joke and funny cartoons in comparison to parts of the cartoon that's not funny. The jokes "tickled" the frontal lobes. The scans also showed activity in the nucleus accumbens. Activity in the nucleus accumbens is likely related to our feeling of mirth after hearing a good joke and our "addiction" to humor. While his research was about humor, the results could help lead to answers and solutions about depression. Parts of the brain that are active during humor are actually abnormal in patients with depression. Eventually brain scans might be used to assess patients with depression and other mood disorders. The research may also explain why some stroke victims lose their sense of humor or suffer other personality changes. The same part of the brain is also associated with social and emotional judgement and planning.