Quiz 9 Study Guide Define the following terms Zeitgeber events that regulate our circadian rhythms suprachiasmatic nucleus SCN what it is and where it is located The biological clock is in the SCN Located above optic chiasm in the hypothalamus Describe the evidence that the SCN generates its own endogenous rhythm Experimental work including lesion studies explant studies and transplant studies in which hosts adopted the donors rhythms have established conclusively that an endogenous clock is located in the suprachiasmatic nucleus of the hypothalamus What is the third eye of birds and amphibians Pineal gland How do mammals get information about the presence or absence of light to the SCN What is the opsin and which neurons contain it Light information goes from the eye to the SCN via the retinohypothalamic pathway retinal ganglion cells that project to the SCN They contain melanopsin photopigment They do not receive input from rods cones Give one example of an ultradian rhythm and of an infradian rhythm Ultradian REM Infradian Menstruation What is the average length of the human circadian rhythm in free running conditions i e no external light changes 24 25 hours Describe briefly the changes over the lifespan in whether one is an early or late riser You re more likely to be a late riser in adolescence You re more likely to be an early riser later in life and very early riser in young children Describe briefly the EEG waves in the 4 slow wave sleep SWS categories Stage 1 SWS vertex spikes Stage 2 SWS sleep spindles Stage 3 SWS marked by the appearance of large delta waves Stage 4 SWS delta waves are present at least 50 of the time The progression through the stages is marked by decreasing frequency and increasing amplitude in the EEG Describe the EEG waves and other physiological characteristics of REM sleep REM sleep is characterized by a return to fast desynchronized EEG activity resembling the awake state complete loss of muscle tone and rapid eye movements Describe the progression of sleep stages in a normal young adult How does that change in older adults Young adult sleep 7 8 hours 45 50 is stage 2 sleep 20 is REM sleep Cycles 90 110 minutes Early cycles stage 3 and 4 SWS later cycles more REM Older adults have less total sleep time frequent awakenings insomnia and loss of stages 3 4 What is the difference between a nightmare and a night terror Nightmares frightening dreams that awaken the sleeper from REM sleep Night terrors sudden arousals from stage 3 or 4 SWS marked by fear and autonomic activity What is unusual about the sleep cycles of dolphins Only one brain hemisphere enters SWS at a time the other remains awake Compare the sleep patterns of young babies less than 4 months old with those of older babies children and adults Infants spend most of their sleep time in REM sleep which may contribute to neural development The proportion of sleep time spent in REM decreases with age sleep in the elderly is characterized by less total sleep time frequent awakenings and complaints of insomnia and a loss of stages 3 and 4 SWS Is it true that we can train ourselves to go without sleep altogether No What are the 5 main functions of sleep Energy conservation Predator avoidance Body restoration Memory consolidation especially in REM Clearing waste products from brain What are the four brain systems that influence SWS arousal and REM Forebrain system displays SWS Brainstem system activates the forebrain Pontine system triggers REM sleep Hypothalamic system affects the other three What transmitter is released by the basal forebrain to SWS GABA What is the effect of lesions of the pons just below the locus coeruleus The area of the pons below the locus coeruleus REM sleep Some neurons below the locus coeruleus are active only during REM sleep They inhibit motoneurons to keep them from firing disabling the motor system during REM sleep What are the characteristics of narcolepsy What is cataplexy Deficiency of what transmitter is implicated in narcolepsy Narcolepsy Have frequent sleep attacks and excessive daytime sleepiness Do not go through SWS before REM sleep May show cataplexy a sudden loss of muscle tone leading to collapse Deficiency of hypocretin is implicated in narcolepsy Where do the hypocretin neurons live Where do they project Hypocretin neurons are located in the lateral hypothalamus Project basal forebrain reticular formation and locus coeruleus They also go to the VTA and activate the mesolimbic dopamine tract What may cause sleep paralysis It may be caused by the pontine REM center continuing to signal for muscle relaxation even when awake During what stage s of sleep do bed wetting and sleep walking occur Bedwetting Sleep enuresis associated with SWS Sleep walking Somnabulism during stages 3 4 SWS What is REM behavior disorder Organized behavior from an asleep person What is sleep apnea What is a treatment for it Breathing may stop or slow down blood oxygen drops rapidly Muscles in the chest and diaphragm may relax too much or pacemaker respiratory neurons in the brain stem may not signal properly Treatment A removable tube in the throat or a CPAP continuous positive airway pressure machine to prevent collapse of the airways What is one way to decrease the chances of sudden infant death syndrome SIDS Putting babies to sleep on their backs prevents suffocation due to apnea How do most sleeping pills work What are some problems with continued use of sleeping pills Bind to GABA receptors throughout the brain Continued Use Makes them ineffective Produces marked changes in sleep patterns that persist even when not taking the drug Can lead to drowsiness and memory gaps What is a recent finding about a benefit of sleep It clears waste products from brain