British researchers have discovered that lack of sleep damages memory and they suggest people take a nap. (File Photo) Photo Gallery >>>

    LONDON, Dec. 2 (Xinhua) -- British researchers have discovered that lack of sleep damages memory and they suggest people take a nap.

    A research team at the Princeton University made the discovery in rats which were deprived of sleep for 72 hours, according to the new latest issue of New Scientist published Saturday.

    In rats, sleep deprivation causes stress hormones to accumulate in a part of the brain called the hippocampus, which in turn stunts the growth of cells that lay down new memories, according to the researchers.

    "The decrease in neuron production coincided with an increase in the major rodent stress hormone, corticosterone," Elizabeth Gould, who led the research, was quoted as saying.

    When the research team stopped production of the hormone in rats by removing their adrenal glands, the animals carried on producing new neurons as normal despite being deprived of sleep.

    "We know that sleep deprivation is stressful, and that it impairs certain types of learning and memory. We concluded that sleep deprivation decreases neurogenesis by elevating stress hormones," Gould said.

    The results tally with earlier studies showing that sleep-deprived people are worse at remembering how to do newly learned tasks than they are normally.

    The results are said to be the first to provide a plausible mechanism explaining how a lack of sleep damages memory, pointing to the importance of sleep in the right hormonal conditions.

    The results explain how shift work might damage memory by producing "a different hormonal milieu", according to the researchers.

    However, the sleep deprivation experienced by the rats is exceptionally long, equivalent to several days in humans, so though sleep deprivation can damage memory, but only "in extreme cases", scientists believe.