脑对短期睡眠缺乏的代偿(英文)
Although many brain researchers believe that sleep deprivation causes a general reduction in brain functioning, this may not be the case. A new report demonstrates that while some parts of the brain do function poorly after sleep deprivation, other parts work harder to compensate.
Researchers led by J. Christian Gillin of the department of psychiatry at the University of California, San Diego, tested 13 young adults on a verbal memory task on two occasions. One test occurred following a normal night’s sleep. The second took place after 35 hours of sleep deprivation. The task involved recalling lists of words and lasted six minutes.
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As the participants were involved in the memory task, the researchers viewed the subjects’ brains using a functional magnetic imaging resonance scan. This imaging tool shows which areas of the brain are active and inactive.
The researchers hypothesized that the prefrontal cortex area of the brain would be less active after sleep deprivation. The prefrontal cortex is located at the outer edge of the brain, just behind the forehead. This area is involved in higher mental functioning, like planning, memory and organization, and is highly active when people are awake. Therefore, they assumed it would be especially vulnerable to sleep deprivation.
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However, contrary to their hypothesis, the investigators found that the prefrontal cortex remained highly active after sleep deprivation. While all subjects performed about 50 percent worse on the verbal memory task after sleep deprivation, those who did better showed more activity in the prefrontal cortex. Those participants who reported feeling more tired also had more highly active prefrontal cortices.
Further, the researchers found that the temporal lobes -- located on the sides of the brain and associated with verbal abilities -- were activated during the rested state but not after sleep deprivation. The parietal lobes -- located on the top middle of the brain and associated with movement and sensation --were more active after sleep deprivation.
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"These findings show that there are dynamic, compensatory changes in cerebral activation during verbal learning after sleep deprivation and implicate the prefrontal cortex and parietal lobes in this compensation," the researchers stated. Their study appears in the February 10 issue of the journal Nature (www.nature.com).
"The brain may be able to compensate for the effects of sleep deprivation while maintaining at least partially intact performance," they wrote.
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Gillin and colleagues added that the decrease in temporal lobe functioning after sleep deprivation may have played a role in the poor verbal performance. "Decreased temporal lobe activity is associated with poor verbal learning in pathological conditions, such as Alzheimer’s disease," the authors wrote.
"Many organs in the body can rest and recover during relaxed wakefulness," according to Jim Horne of the Sleep Research Centre at Loughborough University in England. "But the cerebral cortex seems unable to do this. Only sleep seems to provide real rest for the cortex." Horne authored an editorial that accompanied the study in Nature.
Using human, rather than animal, subjects to perform this type of research is especially important when studying the prefrontal cortex, Horne wrote, because lower animals like the rat "have a relatively poorly developed prefrontal cortex, so the function of sleep for much of the human cortex may differ from the function of sleep in the rat.", 百拇医药
Researchers led by J. Christian Gillin of the department of psychiatry at the University of California, San Diego, tested 13 young adults on a verbal memory task on two occasions. One test occurred following a normal night’s sleep. The second took place after 35 hours of sleep deprivation. The task involved recalling lists of words and lasted six minutes.
, 百拇医药
As the participants were involved in the memory task, the researchers viewed the subjects’ brains using a functional magnetic imaging resonance scan. This imaging tool shows which areas of the brain are active and inactive.
The researchers hypothesized that the prefrontal cortex area of the brain would be less active after sleep deprivation. The prefrontal cortex is located at the outer edge of the brain, just behind the forehead. This area is involved in higher mental functioning, like planning, memory and organization, and is highly active when people are awake. Therefore, they assumed it would be especially vulnerable to sleep deprivation.
, 百拇医药
However, contrary to their hypothesis, the investigators found that the prefrontal cortex remained highly active after sleep deprivation. While all subjects performed about 50 percent worse on the verbal memory task after sleep deprivation, those who did better showed more activity in the prefrontal cortex. Those participants who reported feeling more tired also had more highly active prefrontal cortices.
Further, the researchers found that the temporal lobes -- located on the sides of the brain and associated with verbal abilities -- were activated during the rested state but not after sleep deprivation. The parietal lobes -- located on the top middle of the brain and associated with movement and sensation --were more active after sleep deprivation.
, http://www.100md.com
"These findings show that there are dynamic, compensatory changes in cerebral activation during verbal learning after sleep deprivation and implicate the prefrontal cortex and parietal lobes in this compensation," the researchers stated. Their study appears in the February 10 issue of the journal Nature (www.nature.com).
"The brain may be able to compensate for the effects of sleep deprivation while maintaining at least partially intact performance," they wrote.
, 百拇医药
Gillin and colleagues added that the decrease in temporal lobe functioning after sleep deprivation may have played a role in the poor verbal performance. "Decreased temporal lobe activity is associated with poor verbal learning in pathological conditions, such as Alzheimer’s disease," the authors wrote.
"Many organs in the body can rest and recover during relaxed wakefulness," according to Jim Horne of the Sleep Research Centre at Loughborough University in England. "But the cerebral cortex seems unable to do this. Only sleep seems to provide real rest for the cortex." Horne authored an editorial that accompanied the study in Nature.
Using human, rather than animal, subjects to perform this type of research is especially important when studying the prefrontal cortex, Horne wrote, because lower animals like the rat "have a relatively poorly developed prefrontal cortex, so the function of sleep for much of the human cortex may differ from the function of sleep in the rat.", 百拇医药