Monday, August 24, 2009

The medicine to cure every thing

Laughter

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Contagious Laughter

Laughter is an audible expression or appearance of happiness, or an inward feeling of joy (laughing on the inside). It may ensue (as a physiological reaction) from jokes, tickling, and other stimuli. Inhaling nitrous oxide can also induce laughter; other drugs, such as cannabis, can also induce episodes of strong laughter. Strong laughter can sometimes bring an onset of tears or even moderate muscular pain.

Laughter is found among various animals, as well as in humans. Among the human race, it is a part of human behaviour regulated by the brain, helping humans clarify their intentions in social interaction and providing an emotional context to conversations. Laughter is used as a signal for being part of a group — it signals acceptance and positive interactions with others. Laughter is sometimes seemingly contagious, and the laughter of one person can itself provoke laughter from others as a positive feedback.[1] This may account in part for the popularity of laugh tracks in situation comedy television shows.

Scientifically speaking, laughter is caused by the epiglottis constricting the larynx, causing respiratory upset. The study of humor and laughter, and its psychological and physiological effects on the human body is called gelotology.


Nature of laughter

Laughter is a common response to tickling
Two girls laughing

Recently researchers have shown infants as early as 17 days old have vocal laughing sounds or spontaneous laughter. Early Human Development 2006This conflicts with earlier studies indicating that babies usually start to laugh at about four months of age; J.Y.T. Greig writes, quoting ancient authors, that laughter is not believed to begin in a child until the child is forty days old.[2] "Laughter is Genetic" Robert R. Provine, Ph.D. has spent decades studying laughter. In his interview for WebMD, he indicated "Laughter is a mechanism everyone has; laughter is part of universal human vocabulary. There are thousands of languages, hundreds of thousands of dialects, but everyone speaks laughter in pretty much the same way.” Everyone can laugh. Babies have the ability to laugh before they ever speak. Children who are born blind and deaf still retain the ability to laugh.

Provine argues that “Laughter is primitive, an unconscious vocalization.” And if it seems you laugh more than others, Provine argues that it probably is genetic. In a study of the “Giggle Twins,” two exceptionally happy twins were separated at birth and not reunited until 43 years later. Provine reports that “until they met each other, neither of these exceptionally happy ladies had known anyone who laughed as much as she did.” They reported this even though they both had been brought together by their adoptive parents, whom they indicated were “undemonstrative and dour.” Provine indicates that the twins “inherited some aspects of their laugh sound and pattern, readiness to laugh, and perhaps even taste in humor.” WebMD 2002

Norman Cousins, who suffered from arthritis, developed a recovery program incorporating megadoses of Vitamin C, along with a positive attitude, love, faith, hope, and laughter induced by Marx Brothers films. "I made the joyous discovery that ten minutes of genuine belly laughter had an anesthetic effect and would give me at least two hours of pain-free sleep," he reported. "When the pain-killing effect of the laughter wore off, we would switch on the motion picture projector again and not infrequently, it would lead to another pain-free interval." He wrote about these experiences in several books.[3][4]

Research has noted the similarity in forms of laughter among various primates (humans, gorillas, orang-utans...), suggesting that laughter derives from a common origin among primate species, and has subsequently evolved in each species.[5]

Laughter and the brain

Principal fissures and lobes of the cerebrum viewed laterally. (Frontal lobe is blue, temporal lobe is green.)

Modern neurophysiology states that laughter is linked with the activation of the ventromedial prefrontal cortex, which produces endorphins after a rewarding activity.

Research has shown that parts of the limbic system are involved in laughter[citation needed]. The limbic system is a primitive part of the brain that is involved in emotions and helps us with basic functions necessary for survival. Two structures in the limbic system are involved in producing laughter: the amygdala and the hippocampus[citation needed].

The December 7, 1984 Journal of the American Medical Association describes the neurological causes of laughter as follows:

"Although there is no known 'laugh center' in the brain, its neural mechanism has been the subject of much, albeit inconclusive, speculation. It is evident that its expression depends on neural paths arising in close association with the telencephalic and diencephalic centers concerned with respiration. Wilson considered the mechanism to be in the region of the mesial thalamus, hypothalamus, and subthalamus. Kelly and co-workers, in turn, postulated that the tegmentum near the periaqueductal grey contains the integrating mechanism for emotional expression. Thus, supranuclear pathways, including those from the limbic system that Papez hypothesised to mediate emotional expressions such as laughter, probably come into synaptic relation in the reticular core of the brain stem. So while purely emotional responses such as laughter are mediated by subcortical structures, especially the hypothalamus, and are stereotyped, the cerebral cortex can modulate or suppress them."

Laughter and Health

According to Cindie Leonard,[6]

Solid scientific research demonstrates that laughter offers the following benefits:
  • Lowering blood pressure
  • Strengthening cardiovascular functions
  • Reducing stress hormones
  • Improving circulation
  • Increasing muscle flexion
  • Oxygenating the body by boosting the respiratory system
  • Boosting immune function by raising levels of infection-fighting T-cells, disease-fighting proteins called Gammainterferon and B-cells, which produce disease-destroying antibodies
  • Triggering the release of endorphins, the body's natural painkillers
  • Producing a general sense of well-being

Similar findings have been confirmed by several researchers. For example, an important study in 2006 by the University of Maryland School of Medicine in Baltimore [7]showed a positive link between laughter and a healthy function of blood vessels. According to this research, laughter might cause the tissue that forms the inner lining of blood vessels, the endothelium, to dilate or expand in order to increase blood flow (see also http://www.youtube.com/watch?v=pCrcFcfp-Mg)

Causes

laughing girl
Late 19th century or early 20th century depiction of different stages of laughter on advertising cards

Common causes for laughter are sensations of joy and humor, however other situations may cause laughter as well.

A general theory that explains laughter is called the relief theory. Sigmund Freud summarized it in his theory that laughter releases tension and "psychic energy". This theory is one of the justifications of the beliefs that laughter is beneficial for one's health.[8] This theory explains why laughter can be as a coping mechanism for when one is upset, angry or sad.

Philosopher John Morreall theorizes that human laughter may have its biological origins as a kind of shared expression of relief at the passing of danger.

For example, this is how this theory works in the case of humor: a joke creates an inconsistency, the sentence appears to be not relevant, and we automatically try to understand what the sentence says, supposes, doesn't say, and implies; if we are successful in solving this 'cognitive riddle', and we find out what is hidden within the sentence, and what is the underlying thought, and we bring foreground what was in the background, and we realize that the surprise wasn't dangerous, we eventually laugh with relief. Otherwise, if the inconsistency is not resolved, there is no laugh, as Mack Sennett pointed out: "when the audience is confused, it doesn't laugh" (this is the one of the basic laws of a comedian, called "exactness"). It is important to note that the inconsistency may be resolved, and there may still be no laugh. Due to the fact that laughter is a social mechanism, we may not feel like we are in danger, however, the physical act of laughing may not take place. In addition, the extent of the inconsistency (timing, rhythm, etc) has to do with the amount of danger we feel, and thus how intense or long we laugh. This explanation is also confirmed by modern neurophysiology (see section Laughter and the Brain).

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