PSYCH261 Chapter 8: Module 8.3 Why Sleep? Why REM? Why Dreams?
15 Mar 2018
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Sleep"s origi(cid:374)al fu(cid:374)(cid:272)tio(cid:374) is to save e(cid:374)ergy (cid:894)still a(cid:374) i(cid:373)porta(cid:374)t o(cid:374)e(cid:895) Sleep conserves energy during the inefficient times, when activity would be wasteful and possibly dangerous. During sleep, body temperature decreases & muscle activity decreases saving energy. A: predators get much sleep, and so do species that are unlikely to be attacked during their sleep (such as armadillos) Another apparent function of sleep is improved memory. The brain replays its daily experiences during sleep & brain replays its experience backward as often as forward, and that is sometimes replays less common experiences more often than more common ones. A: the evidence so far points to weakening the synapses that were not strengthened during the day. Weakening these less relevant synapses enables the strengthened ones to stand out by contrast. Infants get more rem and more total sleep than adults do, confirming the pattern that more total sleep predicts a higher percentage of rem sleep.
