yawning controls brain's temp

[Amby 490]

Research from Binghamton University shows there are a whole host of reasons why we yawn, but primarily it is to control the brain’s temperature, Discovery News reported.

“Brains are like computers,” Andrew Gallup, a researcher in the department of biology at Binghamton, who led the study, told Discovery News. “They operate most efficiently when cool, and physical adaptations have evolved to allow maximum cooling of the brain.”

Gallup’s research was published in the journal Animal Behavior.

Gallup and his colleagues studied yawning in parakeets, which have large brains, are subjected to frequent temperature changes and do not participate in contagious yawning, like humans do.

Gallup said contagious yawning is most likely an evolved mechanism that keeps groups of people alert as they “remain vigilant against danger.”

The parakeets were exposed to moderate temperatures, high temperatures and increasing temperatures. The parakeets’ yawning more than doubled when the scientists increased the ambient temperature.

It is believed that yawning acts like a radiator for birds and mammals, cooling the brain and body, and even altering blood flow. Previous studies have suggested yawning functions somewhat like a jolt of energy, as it leads to a heightened state of arousal. (This may be why we yawn when we wake up in the morning).

The research explained why tired people yawn: Fatigue increases brain temperature, which would prompt the body to need a cool-down.

People with health problems also may experience excessive yawning, said Gordon Gallup Jr., a State University of New York at Albany psychologist, who did not work on the study, but is Andrew Gallup’s father, and also an expert on yawning.

"It is interesting to note that instances of excessive yawning in humans may be indicative of brain cooling problems," Gordon Gallup said, indicating that patients who have multiple sclerosis tend to yawn excessively, “and MS involves thermoregulatory dysfunction."

Excessive yawning often precedes the onset of seizures in epileptic patients and can predict migraine headaches, Gordon Gallup added.

http://www.foxnews.com/story/0,2933,467589,00.html

[HAL 9000 96]

Figures. The hypothalamus controls brain temperature, and just anterior to the hypothalamus is an area called the suprachiasmatic nucleus (SCN)- involved in light/dark sensing and neural control. Not surprisingly, there are connections between the SCN and the hypothalamus that are activated when waking up.

[Jenn! 918]

yawn

[HAL 9000 96]

Excess leptin in blood reaching arcuate nucleus of hypothalamus... no more food please. Now SCN is telling hypothalamus to increase body temperature. HAL 9000 feels onrush of... sleep...

[one...two...tree 2,762]

Very interesting.