PS263 Study Guide - Midterm Guide: Melatonin, Thalamus, Slow-Wave Sleep
Document Summary
Endogeneous circannual rhythms (yearly, migration) vs endogeneous circadian rhythms (a day) Rhythms affect waking/sleeping, eating/drinking, urination, hormone secretion, metabolism, moods. Zeitgeber: stimulus that resets rhythm, light for land animals, tides for marine animals etc. Just above optic chiasm and retinohypothalamic path (small branch of optic nerve from retina to scn) alters scn"s settings. Input to path comes from special retinal ganglion cells that respond to light directly and scn uses it to gauge time of day (thus harsh light exposure late in day resets rhythm) Period: a gene that produces the proteins per and tim, promote sleep and inactivity, oscillates over a day based on feedback interactions neurons. Melatonin: secreted by pineal gland (controlled by scn), influences circadian and cirdannual rhythms, increases 2-3 hours before bed making us sleepy. Stage 1 sleep: irregular, jagged, low voltage waves, brain activity less than relaxed wakefulness but higher than other sleep stages.
