PSYB64H3 Lecture Notes - Lecture 8: Circadian Rhythm, Seasonal Affective Disorder, Sleep Spindle
12 Jul 2015
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Document Summary
Circadian rhythms: zeitgebers, any external cue that synchronizes an organism"s internal clock, variations in sleep patterns, night owls versus larks. Daylight saving time in spring requires a phase advance, and can produce symptoms similar to jet lag. The time change in fall is equivalent to a phase delay, and causes little disruption for most people. Per, tim, and clock (genes and their protein products) Scn regulates and responds to this hormone secreted by pineal body. This hormone also fluctuates with patterns of waking and sleeping. Stress-induced high cortisol levels during the night are correlated with poor sleep quality. Lesions of suprachiasmatic nucleus abolish free-running rhythms: activity in suprachiasmatic nucleus correlates with circadian rhythms. Isolated suprachiasmatic nucleus continues to cycle: transplanted suprachiasmatic nucleus imparts rhythm of the donor. 14-16 hours a day, 50 % time in rem: puberty. 20 % of time in rem and also a substatial decrease in stage 3 and 4.
