PSYCH261 Chapter Notes - Chapter 8: Sleep Spindle, Alpha Wave, Polysomnography

• School: University of Waterloo
• Department: Psychology
• Course: PSYCH261
• Professor: Daniel Smilek

Document Summary

Module 8. 2 stages of sleep and brain mechanisms. Sleep is a state that the brain actively produces, characterized by decreased response to stimuli. In contrast, coma is an extended period of unconsciousness caused by head trauma, stroke, or disease. Someone in a vegetative state alternated between periods of sleep and moderate arousal, although even during the more aroused state, the person shows no awareness of surroundings and no purposeful behaviour. A minimally conscious state is one state higher, with occasional, brief periods of purposeful actions and a limited amount of speech comprehension. Brain death is a condition with no sign of brain activity and no response to any stimulus. Polysomnography: a combination of eeg and eye-movement records. Alpha waves are characteristic of relaxation, not of all wakefulness. The most prominent characteristics of stage 2 are sleep spindles and k-complexes. A sleep spindle results from oscillating interactions between cells in the thalamus and the cortex.