PSY 111 Lecture Notes - Lecture 13: Seasonal Affective Disorder, Circadian Rhythm, Delta Wave
Document Summary
Circadian rhythms daily biological cycles within the body that occur on a 24 hour cycle. Most rhythms regulated by brain"s suprachiasmatic nuclei (scn) in the hypothalamus: linked to pineal gland, which secretes melatonin (relaxing hormone) at night when scn is less active to reduce secretion. Gradual and sudden environmental changes can disrupt our circadian rhythms: seasonal affective disorder cyclic tendency to become psychologically depressed during certain months of the year, jet lag caused by change in typical daily time cycle. Brain"s electrical activity mostly beta waves (high frequency, low amplitude) while awake. Alpha waves (lower frequency, slightly higher amplitude) while relaxed and drowsy. Within 60-90 minutes of falling asleep, stages proceed through 1-2-3-4-3-2. Newborns began by sleeping 16 hours a day, almost half in rem. Both genetics and environment can affect length of sleep. Sleep deprivation causes negative impact on functioning, mood, cognition, and physical performance.
