Sunday, September 03, 2006

 

Model Of Internal Clocks Reveals How Jet Lag Disrupts The System

Symptoms of extreme jet lag may result from the body overshooting as it tries to adjust to particularly large leaps forward in time, suggests new research from the University of Massachusetts Amherst that models circadian rhythms in rats...

The analytical model, by UMass Amherst's Hava Siegelmann, appears in the current issue of the Journal of Biological Rhythms. Tanya Leise of Amherst College co-authored the work.

The body's sleep and wakefulness patterns are just two of the physiological processes that run on a roughly 24-hour-cycle, or circadian clock, explains Siegelmann. These and other processes are coordinated by the master pacemaker, or clock, an area of the brain with a natural cycle that is approximately 24 hours long. In mammals, the master clock is a group of cells called the suprachiasmatic nucleus (SCN), which lies at the base of the hypothalamus. The SCN receives information on daylight sent from the eyes' optic nerve and can be reset by environmental cues such as light.

Recent research suggests that every cell in the body actually has its own clock - liver cells prepare for digestion at particular times of day; patterns of hormone production and brain activity exhibit cyclic peaks and valleys, says Siegelmann.
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News report based on "Dynamics of a Multistage Circadian System" (Abstract).

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