1Listen to the audio lecture while viewing these slidesPsychology 100Introduction to Psychology1Chapter 6: ConsciousnessModule 6.2: Sleep, Part 12Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologySleep and Dreaming: Overview• Biological rhythms• Stages and characteristics of sleep• What is the function of sleep?• Consequences of sleep deprivation• What is the function of REM sleep and dreaming?• Sleep disorders3Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyBiological Rhythms• Physical cycles including:• Circadian rhythms: Biological activities that rise and fall along a 24-hour cycle• Triggered at appropriate times by brain structures called biological clocks• Example: Superchiasmatic nucleus• Set by factors in the environment, particularly light4Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyFig. 6.45Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyStudying Sleep: EEG Recordings• Short for electroencephalograph• How they are collected:• Electrodes pasted to scalp (painless)• Changes in electrical potentials of brain cells recorded by tracing lines• Also called: “Brain waves”• EEGs reveal regular, cyclic changes in brain activity during sleepFig. 6.56Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyStages of Sleep• Stage 1: Theta waves appear• Light sleep; person may claim to still be awake• Stage 2: Sleep spindles, K complexes• Person definitely asleep, but may respond to some events, such as noises• Stage 3 and stage 4: Delta activity• Very deep sleep; nonresponsive to most stimuli and slow to awake27Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyFig. 6.68Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyREM Sleep• Begins 70-90 minutes into the sleep cycle• Changes in physiological pattern including increased heart rate, darting eyes, twitching in hands, feet, face• EEG: Resembles waking state•Dreaming:• Most people awakened during REM report dreaming• Might dream during some non-REM sleep, though9Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyThe Sleep Cycle• Cycle through stages, in order, 4-5 times a night• REM interspersed with other stages• About 90 minutes per cycle• Time in each stage varies• REM dominates later stages, especially right before waking10Psyc 100 Psyc 100 –– Introduction to PsychologyIntroduction to PsychologyFig.