Contact:
Mag. My Hue McGowran
Phone: +43-1-81140-308
E-Mail: mcgowran@newsfox.com
| Pressbox | 
|
Aberdeen (pte023/21.06.2005/11:33) - Scientists have discovered that two distinct areas of the brain in humans and mammals regulate the internal 'body clock', which distinguish between waking up and going to sleep.
The scientists, from the Aberdeen http://www.abdn.ac.uk and Nottingham http://www.nottingham.ac.uk universities, theorise in the journal Current Biology http://www.current-biology.com that the interaction between these two clocks has to do with how we prepare for the change in seasons in advance.
Dr David Hazlerigg of Aberdeen University speculated that a fault in this system may trigger the condition Seasonal Affective Disorder or SAD, which can cause deep depression in sufferers during long periods of darkness in winter. He also suggests that an understanding of the 'two-clock' theory may promote a deeper knowledge of SAD.
Dr Francis Ebling of Nottingham University says that the idea of a 'morning' and 'evening' clock could be used as a basis for such research. "The idea of clocks is that they predict changes in the outside world - so rather than responding to light [at daybreak] your body gets you ready in advance." He points out that animals living outside the equatorial regions, where climate change is minimal, have developed these 'clocks' to prepare for winter.
"The ability to tell seasons is extraordinarily important for any organism living in temperate or Arctic climates," Dr Ebling said.
"You are more efficient if you can predict the seasons in advance, so you can get ready for winter - store up fat in the summer and, if you're a sheep, begin breeding in October, so the lambs are born in the spring," Ebling explained. "If the sheep waited until the grass started growing they would miss out because it takes five months for a lamb to develop."
The researchers' paper shows how the length of time between morning and evening is measured. "It shows these two [clocks], morning and evening, are two different parts of this one structure at the base of the brain, part of the hypothalamus, which is a very primitive part of the brain," Dr Ebling said. "Although some animals use temperature, measuring the length of the day is the most robust method. It's the perfect cue to look into."
The scientists will continue their research, but psychologist Dr Cynthia McVey, of Glasgow Caledonian University, said the two-clock theory might be feasible in explaining SAD. "If you were less sensitive and less aware of the increase in light and more sensitive and more aware of the decrease in light then your perception of the day would be gloomier," she said.
"And if your body is slow to perceive the light dawning and quick to perceive that the light is getting dimmer then the day is going to be shortened because you are not as awake," McVey added.
(end)
|
|
