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[ti:The Stuff of Dreams]
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[00:01.49]Lesson 19
[00:03.88]The stuff of dreams
[00:12.89]What is going on when a person experiences rapid eye-movements during sleep?
[00:21.48]It is fairly clear that the sleeping period must have some function, and because there is so much of it the function would seem to be important.
[00:32.48]Speculations about its nature have been going on for literally thousands of years,
[00:38.80]and one odd finding that makes the problem puzzling is that it looks very much as if sleeping is not simply a matter of giving the body a rest.
[00:48.75]'Rest', in terms of muscle relaxation and so on, can be achieved by a brief period lying, or even sitting down.
[00:58.93]The body's tissues are self-repairing and self-restoring to a degree, and function best when more or less continuously active.
[01:09.16]In fact a basic amount of movement occurs during sleep which is specifically concerned with preventing muscle inactivity.
[01:19.58]If it is not a question of resting the body, then perhaps it is the brain that needs resting?
[01:26.60]This might be a plausible hypothesis were it not for two factors.
[01:31.71]First the electroencephalograph (which is simply a device for recording the electrical activity of the brain by attaching electrodes to the scalp)
[01:42.12]shows that while there is a change in the pattern of activity during sleep, there is no evidence that the total amount of activity is any less.