Chapter 6

2 3 4 light levels 5 so less drowsiness retina greater

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Unformatted text preview: SNESS low frequency and high amplitude Circadian Rhythms – 24 hr biological cycles • • Regulation of sleep/ body functions Physiological pathway of the biological clock: 1. 2. 3. 4. Light levels 5. So, less drowsiness retina > greater activity in the neurons of the suprachinasmatic nucleus (hypothalaus) Causes lower secretion of melatonin (pineal gland) Examples of circadian rhythms Examples of circadian rhythms. Why? -genetics -environment Variation in sleep need Variation in sleep needs Free running Circadian rhythm. Changes in sleep periods of a subject isolated from day-night cycle 25 * Shift to … hour cycle Retire for sleep later and later with each in isolation. WHAT HAPPENS WHEN WE SUDDENLY ALTER OUR TIME SCHEDULE ? …. Circadian rhythms and jet lag Easier to adjust when traveling west b/c extended day more like free running Circadian rhythm. - SLEEP RESEARCH • Sleep/Waking Research Instruments: 1. Electroencephalograph (EEG) brain electrical activity – 2. Electromyograph - muscle activity 3. Electrooculograph – eye movements • Other bodily functions also observed Sleep Stages: Cycling Through Sleep • Stage 1: • brief, transitional (1-7 minutes) (1-7 minutes) – aplha---> theta – hypnic jerks • Stage 2: sleep spindles (10-25 minutes) • Stages 3 & 4 : slow-wave • * deep sleep (30 min) * Delta waves • REM: EEG similar to awake,vivid dreaming (initially a few minutes, progressively longer as cycle through the stages.) EEG PATTERNS & WAKEFULNESS An overview of the cycle of sleep An overview of the cycle of sleep. Changes in sleep patterns over the life span. With age - <sleep per night - < REM sleep Brain Structures: • No single brain system regulates sleep • Many integrated systems and neurtransmitters SLEEP Occurs when: 1. 2. (ARAS). Ascending Reticular Activating System is inhibited and Hypnogenic 催眠 system is activated (basal forebrain and brain stem) • Pons is critical for REM sleep as it contains "Sleep-on" neurons that activate different regions that control...
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