Unit 3 Notes Sleep and Circadian Rhythms ch 14 Methods of studying sleep 10 29 13 timed to be 30 seconds Organization of sleep brain o Polygraphs attach electrodes to the scalp on the top towards the back to monitor the electrical activity in the brain during sleep puts it on paper Electroencephalograms EEG monitors electrical activity in the Electromyograms EMG monitors electrical activity in the muscles when you sleep generally attached under the chin Attaching under the chin works well because your chin relaxes when you sleep sensitive to sleep onset Electrooculograms EOG Monitors eye movement while you sleep electrodes placed near the eye o Epoch In terms of sleep recordings each page printed by the polygraph o Wake Alert beta activity vs relaxed alpha activity Beta activity low random electrical activity very fast Alpha activity higher slower electrical activity o Stage 1 Low voltage EEG decreased EMG Brain slows down a little bit theta activity doesn t show up very well on an EEG Dramatic decrease very sudden in muscle tone activity Ex Head bobbing o Stage 2 Sleep spindles K complexes slight decrease in EMG Noticeable EEG changes Sleep spindles similar to alpha waves but faster occur very quickly goes back to slow beta K complex slowing down of the electrical activity in the brain EMG slows down a little more o Stage 3 Between 20 and 50 delta waves in one Epoch Brain really slows down deep sleep Not much change in muscle activity o Stage 4 50 delta waves in one Epoch Not much change in muscle activity Sleep walking usually happens here sometimes stage 3 o REM Low Voltage EEG decreased EMG The brain wakes up in terms of brain activity Muscle activity drops to nothing Area in the pons turns your voluntary muscle movement off Other areas turn on twitches ex Eye movements finger twitches Dream in REM sleep Sleep paralysis can occur as we re coming out of REM on off switch that turns our voluntary movements on off is a little out of sync with our wake sleep cycle o Other terms Non Rem Sleep NREM all the stages of sleep that aren t REM SWS slow wave sleep referring specifically to stages 3 and 4 because of slow delta waves Continuity of Sleep o NREM REM Cycles we cycle through all stages of sleep continuously 90 minute cycles Stage 1 and 2 are very short quick transition into stages 3 and 4 where growth hormone and protein synthesis is released then quick transition to REM Go from stage 4 into REM in about less than 30 seconds First period of REM sleep is usually very short 5 10 min Quick transition again back to NREM stages REM starts off very quick at the beginning of the night very long at the end of the night By the end of the night stage 2 REM REM Sleep o Pons o Dreams Locus coeruleus turns muscle tone on off as you go in and out of REM sleep Other areas of Pons responsible for muscle twitches including eye movements in REM sleep Heart rate breathing are irregular in REM because of the Pons Only remember a dream if you wake up in REM Hippocampus not active during REM so we can t remember them Dreams thoughts without conscious control so they re normally weird Meaning We can t attach too much meaning b c your brain is awake and producing thoughts while your body is asleep Thoughts have no conscious control they may have meaning but nothing extreme o We normally dream about what we re worried about Function o Reworking what we re worried about o May wake up with an idea about what we should do in a certain situation D j vu one hemisphere of the brain may process information slightly faster than the other sees it first then other hemisphere registers it College Student Sleep o Turns out we re not that sleep deprived o On average we get about 7 7 5 hours a night 9 on the weekends o Major issue Irregular sleep patterns We train our brains to sleep whenever we can Solution Regulate our sleep times Class Notes 10 31 13 Ontogeny of Sleep Development of sleep across lifespan o Newborns Polyphasic sleep 16 17 hours day 50 REM 50 NREM Almost all Stages 3 and 4 o Children 9 11 hrs day By about 2 years old 20 25 REM sleep Rest NREM most is slow wave sleep stages 3 and 4 o Adolescents 12 25 8 10 hrs day 20 25 REM NREM 25 30 slow wave sleep rest stage 2 o Adults 25 50ish 7 8 hrs day o Older Adults 5 8 hrs day Delta activity SWS Brain doesn t create the same type of delta waves during Frequent awakenings shortened sleep Endogenous Cycles cycles our body produces for us sleep o Circadian Rhythms Internal rhythms our body naturally produces that are about 24 hours in length Suprachiasmatic nucleus SCN monitors circadian rhythms endogenous cycles Located at base of hypothalamus just above the optic Maintains clock through protein synthesis caused by exposure to chiasm the sun Sun forces our body into a 24 hour rhythm o Bunker Studies Done by German scientists in WWII bunkers Paid grad students to live in a bunker for a month No sunlight no time cues radios tvs clocks etc Told to try and sleep at night work during the day Found that without the sun these people would go to sleep about an hour later every night get up an hour later every day Ran a 25 hour internal rhythm Desynchronization ex Not being tired when we know we should be not being hungry when we know we should be etc We have nonvisual photoreceptors in the eye that are not rods OR cones but part of the ganglion cells just light dectectors o Light and SCN Detect light through Melanopsin in the ganglion cells Melanopsin makes ganglion cells light sensitive Ganglion cells send this light info directly to the SCN o Melatonin Preparation for sleep and seasonal rhythms Ex Melatonin involved in the hibernation of some animals Does these things through the Pineal Gland Melanopsin sends info to SCN influences the pituitary gland then controls the pineal gland releases melatonin We naturally secrete Melatonin as lights go dim People may have insomnia today because our artificial lights are bright enough to mess up our melatonin secretion As we age we make less and less melatonin Sleep Onset Sleepiness o Why can t we sleep when we want to We get sleepy the longer we re awake Circadian factor rhythm makes us naturally awake during the day naturally sleepy at night Daily life has 2 factors that keep us oriented to sleeping at night The recuperative factor more sleepy the longer you re awake Circadian factor Shiftwork o Working during the day is best o Night shifts create trouble Working when brain wants to sleep Decreased attention and