 | Laughter and theBrain |  |
| Laughter and theBrain | |
  Laughter...it's fun...it'sfunny...but why do we do it? Why can't you tickle yourself? What part ofthe brain is responsible for laughter and humor? There are not manyanswers to these questions because there have not been very manyexperiments on the topic of laughter. Part of the reason for this is thatlaughter is not a big clinical problem. People do not go to the doctorbecause they are laughing and feel good. On the other hand, there are asome people with brain damage that MAY cause | Contents of this Page
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 A paper published recently in the journal Nature (vol.391, page 650, 1998) called "Electric Current Stimulates Laughter" has provided a bit more information about how the brain is involved withlaughter. The paper discussedthe case of a 16 yr. old girl named "A.K." who was having surgery tocontrol seizures due to epilepsy. During surgery, the doctorselectrically stimulated A.K.'s cerebral cortex to map her brain. Mappingof the brain is done to determine the function of different brain areasand to make sure that brain tissue that will be removed does not have animportant function. |
 The doctors found that A.K. always laughed whenthey stimulated a small 2 cm by 2 cm area on her left superior frontalgyrus (part of the frontal lobe of thebrain). This brain area is part of the supplementary motor area. Unlike laughter that happens after brain damage, the laughter that wasproduced by electrical stimulation in A.K. also had a sense of "merrimentor mirth". Also, A.K. did NOT have the type of epilepsy withgelastic seizures. Each time her brain was stimulated, A.K. laughed andsaid that something was funny. The thing that she said caused her tolaugh was different each time. A.K. laughed first, then made up a storythat was funny to her. Most people first know what is funny, then theylaugh.The authors of the paper believe that the area of the brain that causedlaughter in A.K. is part of a larger circuit involving several differentbrain areas. Different parts of the circuit may be important for:
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 So, now we knowa little more about what part of the brainis responsible for humor. This does not explain why we laugh or why wedon't laugh when we tickle ourselves. Believe it or not, there has beensome research into this area. In fact, researchers at theUniversity of California in San Diego have even constructed a "TickleMachine". For these scientists, tickling is no laughing matter!
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 Is Laughter the Best Medicine? The physiological study of laughter has its own name· However, laughter is NOT ALWAYS good medicine. There are a few cases whenlaughing actually CAUSED a heart attack or a stroke. Also, immediatelyafter abdominal surgery, people should not laugh too hard because theycould tear out their stitches accidentally. Care should also be used inpatients with broken ribs. So, try not to be too funny around thesepeople. Further research into how a positive attitude affects a person's healthneed to be done. This will give a whole new meaning to thephrase: |
References
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Some scientists believethatlaughing caused by tickling is a built-in reflex since even babies do it. If this is true, then you should be able to tickle yourself...but youcan't, can you? Even if you try to tickle yourself in exactly the sameway that another person tickles you, you don't laugh. Why is this? Theinformation 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 notension or surprise. How the brain uses this information about tensionand surprise is still a mystery, but there is some evidence that the 
Everyone smiles and laughs. Evenmonkeys and apes have some facialexpressions that are similar to human smiles. It is possible thatsmiling, laughing and tickling are used to create bonds between babies andparents. When a parent tickles a baby and the baby responds with a smileor laugh, the parent laughs and smiles too. In this way, the baby andparent get to know one another and the baby learns all about laughter bywatching and responding to a parent.
Research has shown that laughing is more than just a person's voice andmovement. Laughter requires the coordination of many muscles throughoutthe body. Laughter also: 
Can laughter improve health?It may be a good way for people to relax since muscle tension is reducedafter laughing. There are some cases when a good deep laugh may helppeople with respiratory problems by clearing mucus and aidingventiliation. Perhaps laughing can also help cardiac patients by givingthe heart a bit of a workout. Some hospitals even have their own 
How laughter affects the nervoussystem and rest of the body is not completely understood. A new area ofneuroscience called "Psychoneuroimmunology" studiesthe interactions between the brain and the immune system. The field ofpsychoneuroimmunology combines the methods and techniques of psychology,neuroscience and immunology. Psychoneuroimmunological experiments usuallyfocus on how stress affects the nervous system and disease states. Laughter has been shown to cause changes in the autonomic nervous systemand also to alter stress hormone and neurotransmitter levels. Forexample, 60 min. of watching a video with the comedian "Gallagher"caused reductions in the levels of:
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