Download Sleep – Circadian Rhythms, EEG, Stages and Dreams - Lecture Notes | PSYC 2004 and more Study notes Psychology in PDF only on Docsity! PSYCH Mar 03 Sleep – Circadian Rhythms - The sleep cycle is based on circadian rhythms (internal patterns of bodily functions over a 24- hour period) o A key brain area is the suprachiasmatic nucleus (SCN) in the hypothalamus; it influences the hypothalamus and reticular formation to keep our temperature, hunger, sleep, etc. on a synchronized schedule. o SCN receives input from the retina, getting information about light / dark cycles. - Disruptions to the circadian rhythm… o Often due to shifting work schedules, het lag, pulling an “all nighter” o Can lead to thinking less clearly, inattentiveness, and feeling sleepy. EEGs - Graphically record brain-wave activity through electrodes on the scalp and forehead. - EEG waves vary in frequency and amplitude. o Can have lower / higher amplitude or a mixture of both o Frequency stays the same, only thing that changes is speed o High and mixed frequency : Low amplitude Waking Stage 1 Some of Stage 2 o Lower frequency : High amplitude Some of Stage 2 Stage 3 Stage 4 o High frequency : Low amplitude R.E.M sleep Stages - Occur at different points all throughout the night - REM = dream sleep - Stage 1 = light sleep - Stage 2 = slower eye movements, brain waves - Stage 3 & 4 = deep sleep, low frequency o A full cycle of stages takes approximately 90 – 120 minutes o More deep sleep early, longer bouts of REM later - In the stages of sleep, particularly deep sleep, the body relaxes, and EEG activity, heart rate, and breathing slow. - REM (Rapid Eye Movement) sleep: o Physiologically, very similar to being awake o Many muscles are paralyzed. o Sleepwalking cannot occur during REM. o Dreams occur in other stages, too, but they’re more vivid, long-lasting, and detailed in REM sleep. - As we get older, we have more trouble sleeping through the night, and get less REM sleep. o Sleep deprivation can cause cognitive, motor impairment.
