Philosophers and psychologists address arousal and incongruities, but finally laughter is a bodily thing. It has a purely physiological existence, separate from any psychological sense of amusement, triumph, relief or gratification. Ernst Kris, psychoanalytic writer, notes that laughter involves much of the same physiological processes no matter what its tine : ironic, hilarious, teasing, whatever.

So, this is how laughter becomes laughter : 

:) Blood comes from the right cavity of the heart through the pulmonary artery inflates the lungs, driving the air out of them. 

:) This act pulls abruptly on the diaphragm, to which it is connected with a strong membrane. 

:) The vacillating and trembling diaphragm in turn shakes the chest, following which there is a similar compression of the lungs, which breaks up the voice. 

:) This is accompanied by the muscular phenomenon, which consists of the contractions of the larynx and epiglottis, and the spasmodic contractions of the large and small zygomatic (facial) muscles. 

Theophrarto Renaudot, a French doctor, is certain that laughing and sneezing is similar. Actually laughing is an act of exhaling. (No one can laugh and inhale at the same time right?) By breathing out air, it can bring us a sense of relief. The Greek uses a wonderful word "gelao", which means shining, to describe laughter. This is because laughing brightens up our faces and lets our red lips stretch on our white teeth, which brings light and colours.

Laughter on the Brain

The physiological study of laughter has its own name -- gelotology. I guess many of you know that certain parts of the brain are responsible for certain human functions. For example, emotional responses are the function of the brain's largest region, the frontal lobe. But researchers have learned that the production of laughter is involved with various regions of the brain.

For example, Derks traced the pattern of brainwave activity in subjects responding to humorous things. Subjects were hooked up to an electroencephalograph (EEG) and their brain activity was measured when they laughed. Within 4/10 of a second of exposure to something funny, an electrical wave moved regularly through the cerebral cortex, the largest part of the brain. If the wave took a negative charge, laughter resulted. If it maintained a positive charge, no response was given, researchers said.

During the experiment, researchers observed the following specific activities:

· The left side of the cortex (the layer of cells that covers the entire surface of the forebrain) analyzed the words and structure of the joke.

· The brain's large frontal lobe, which is involved in social emotional responses, became very active.

· The right hemisphere of the cortex carried out the intellectual analysis required to "get" the joke.

· Brainwave activity then spread to the sensory processing area of the occipital lobe (the area on the back of the head that contains the cells that process visual signals).

· Stimulation of the motor sections evoked physical responses to the joke.

This is different from what happens with emotional responses. Emotional responses appear to be confined to specific areas of the brain, while laughter seems to be produced via a circuit that runs through many regions of the brain. (This means that damage to any of these regions can impair one's sense of humor and response to humor......)

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