Outline Types of Rhythms Endogenous Clocks Sleep Sleep Disorders Sleep Wake Stages Beta rhythms awake and alert 15 to 20 Hz Alpha rhythms awake and relaxed 8 to 12 Hz Sleep Wake Stages Sleep characterized by rapid eye movement REM sleep and non REM nREM sleep or slow wave sleep SWS Sleep Wake Stages Stage 1 similar to awake EEG Heart rate and muscle tension decrease Theta rhythm of 4 7 Hz Stage 2 Sleep spindles occur in 0 5 sec bursts of 12 to 14 Hz K complexes are sharp negative EEG potentials Sleep Wake Stages Stage 3 Delta waves large amplitude very slow waves of about 1 Hz Stage 4 Delta waves are present about half the time REM sleep Rapid eye movement Active EEG with smallamplitude high frequency waves like an awake person Muscles are relaxed called paradoxical sleep A typical night of sleep Sleep time ranges from 7 8 hours 45 50 is stage 2 sleep 20 is REM sleep Cycles last 90 110 minutes but cycles early in the night have more stage 3 and 4 SWS and later cycles have more REM sleep Sleep Across the Lifespan Functions of Sleep Restorative Metabolism Energy expenditure Adaptive Eating efficiency Vulnerability to predators Dreaming During REM and NREM Dreams occur during both REM and NREM sleep Vivid dreams occur during REM sleep characterized by Visual imagery Sense that the dreamer is there Dream Theories Hobson McCarley Activation Synthesis Theory Content of dream reflects ongoing neural activity Crick Mitchison Forget irrelevant information Winson Integrate sensory experiences with memories Reveonsuo Threat simulation Replay of Experience During Sleep Brain Mechanisms Control of wakefulness Reticular formation Helps maintain desynchronized activity in cerebral cortex Without input cortical neuronal activity becomes synchronized Brain Mechanisms Control of wakefulness Locus coeruleus Releases norepinephrine Anterior raphe nuclei Releases serotonin Both areas have diverse and rich projections to many brain areas Brain Mechanisms Control of NREM sleep Preoptic area of hypothalamus Inhibits wakefulness circuits NREM on cells LC RN Norepinephrine and serotonin release decreases preparing brain for REM sleep Brain Mechanisms Control of REM sleep REM on area rostral pontine reticular formation Responsible for rapid eye movement and muscle paralysis REM off areas LC and RN Decrease before REM sleep dis inhibits the pons After 30 min of REM the LC and RN reactivate inhibiting pons Wakefulness SWS and REM REM vs Waking top Secondary visual cortex and limbic system more active during REM Prefrontal cortex less active during REM REM vs SWS lower Most of the brain is more active during REM than during SWS Outline Types of Rhythms Endogenous Clocks Sleep Sleep Disorders Sleep Disorders Dyssomnias abnormality in the amount quality or timing of sleep Insomnia Narcolepsy Hypersomnia Parasomnias abnormal behavior or physiology during sleep Nightmares Night terrors Somnambulism sleepwalking Restless leg syndrome Insomnia A common sleep problem People with insomnia may have Trouble falling asleep onset insomnia Many awakenings during the night with difficulty going back to sleep maintenance insomnia Fitful sleep Sleep state misperception pseudo insomnia During the day people with insomnia may be Drowsy Anxious and irritable Forgetful with difficulty concentrating How common is insomnia More than half of adults in the U S said they experienced insomnia at least a few nights a week during the past year Nearly one third said they had insomnia nearly every night Increases with age The most frequent health complaint after pain Twice as common in women as in men Treatment is either behavioral or pharmacological sedatives Narcolepsy Unwanted sleep attacks Symptoms Excessive daytime sleepiness Cataplexy sudden muscular paralysis while conscious Sleep paralysis similar loss of muscle control during transition between sleeping waking Do not go through SWS before REM sleep Genetic component 1 2 among first degree relatives No known cure only symptom relief Hypersomnia Characterized by excessive daytime sleepiness Lack of or interrupted sleep at night Nap frequently and inappropriately Anxiety irritation restlessness slower thinking memory difficulty Comorbid with many psychological disorders Nightmares vs Night Terrors Night Terrors Nightmares Time of Night Within four hours of bedtime Late in sleep cycle State on waking Disoriented confused Upset Scared Response to caregivers Unaware of presence inconsolable Comforted Memory of events None unless fully awakened Vivid recall of dream Return to sleep Rapid unless fully awakened Often delayed by fear Sleep Stage Partial arousal from deep slow wave sleep REM sleep Somnambulism Sleepwalking Occurs during deepest stages of Slow Wave Sleep They can be woken up without harm REM Behavior Disorder REM paralysis absent or minimized Act out dramatic and or violent dreams Shouting and grunting Voluntary muscles become tonic or tensely contracted