HEALTH: Secret behind sound sleep – for peace of mind ?!!
FROM THE TELEGRAPH SPECIAL CORRESPONDENT
New Delhi, Aug. 11: A set of brain waves identified by scientists nearly 80 years ago may explain why some people continue to sleep soundly despite noise, while others are stirred awake by even feeble sounds.
Medical researchers at the Harvard Medical School have shown that oscillations called sleep spindles seen on electroencephalography readings of sleeping people may be used to distinguish between sound sleepers and those easily awakened.
Sleep spindles were among the first brain rhythms to be observed when scientists began to analyse sleep physiology during the 1930s. But their biological functions remained largely unknown until a few years ago when researchers discovered that these buzzes of activity are generated by the thalamus — a region of the brain that, among doing other things, regulates sensory information hitting the brain.
“Since the thalamus is a gateway of sensory information into the brain, it has been hypothesised that spindles are markers of the blockage of noises during sleep,” said Jeffrey Ellenbogen, the lead investigator of the Harvard study.
The study by Ellenbogen and his colleagues is among the first to establish a role for sleep spindles in the soundness of sleep — the more the number of spindles a person has, the more stable the sleep, despite potentially disturbing noise.
In the studies, the researchers exposed 12 healthy human volunteers to noises such as a ringing telephone, or road or air traffic to simulate a noisy night. Their findings, published today in the journal Current Biology, demonstrate that persons whose brains generated more sleep spindles during a quiet night exhibited higher tolerance for noise during a subsequent noisy night of sleep.
“It turns out that (individuals with) more sleep spindles means more stable sleep, even in the face of noise and even when we control for the various stages of sleep,” Ellenbogen told The Telegraph in an interview.
The researchers caution that exactly how much sleep spindles contribute to the stability of sleep needs to be further investigated. Previous studies have indicated that noise tolerance and spindles rates reduce with age.
But the new findings also appear to explain earlier results that indicated that spindle rates could influence learning potential. While shielding sleep from being disturbed, abundant spindles may also consolidate memory and aid learning.
The results may spawn new strategies to improve sleep.
“The idea is to enhance this naturally occurring brain rhythm that protects sleep. We have a lot of work to do before using this in people, mainly because we have to be absolutely clear that it is safe and effective,” Ellenbogen said.
“But whether it’s next year or the next decade,” he said, “this research will lay the groundwork for brain-based solutions to noisy environments.”