PSYA01H3 Chapter Notes - Chapter 5.4: Slow-Wave Sleep, Hypnic Jerk, Sleep Deprivation
Document Summary
As you begin to fall asleep, the busy, task-oriented thoughts of waking mind are replaced by wandering thoughts and images. This pre-sleep consciousness is called the hypnagogic state. On some rare nights you may experience a hypnic jerk, a sudden quiver or sensation of dropping. Eventually, your presence of mind goes away entirely. Dreams come, and finally the glimmerings of waking consciousness return in a foggy and imprecise form as you enter post-sleep consciousness (the hypnopompic state) and then awake. The eeg recordings revealed a regular pattern of changes in electrical activity in the brain accompanying the circadian cycle. During waking, these changes involve alternation between high-frequency activity (beta waves) during alertness and low-frequency activity (alpha waves) during relaxation. The largest changes in eeg occur during sleep. First stage the eeg moves to frequency patterns even lower than alpha waves (theta waves)
