psych-133-midterm-1.pdf

lOMoARcPSD|17698592 Psych 133 Midterm 1 Psychology Of Sleep (University of California, Berkeley) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloa...

lOMoARcPSD|17698592 Psych 133 Midterm 1 Psychology Of Sleep (University of California, Berkeley) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 Lecture 2: Sleep Basics - Measurement | Types: 1) Phenomenology: a) Loss of external awareness b) Disconnected thoughts → especially during transition c) Disorientation in time and space → losing track d) Images and dreams - Self reported experience 2) Behavior a) Horizontal position b) Low muscle tone c) 24hr (circadian) time (day vs time) d) Non-responsive, but reversible (rebound after deprivation) 3) Physiology: the gold standard a) Changes in the brain b) Changes in the body - Polysomnography (PSG): Measuring Sleep 1) Electroencephalography (EEG): measures electrical activity of the brain a) Brain Waves b) 2) Electrooculography (EOG): an electrode placed near the eye will record the change in voltage as the eye moves a) Eye movements b) 3) Electromyography (EMG): measures electrical activity of the muscles, usually recorded from under the chin and on the face a) Muscle tension b) - Sometimes need 1st night of adaptation - Types of Sleep - Sleep Stages: 1) Non-Rapid Eye movement sleep (NREM) → increase in depth a) Stage 1 b) Stage 2 c) Slow-Wave Sleep (SWS) Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 i) Stage 3 ii) Stage 4 2) Rapid Eye movement sleep (REM) → PGO waves and transition in dream sleep a) REM sleep Paralysis: All nerve connections to your skeletal muscles are inhibited, causing paralysis b) Paralysis occurs to protect body from mind’s dreams - NREM/REM only discovered in 1953 (Nathaniel Kleitman and Eugene Aserinsky) - Hypnogram: diagram demonstrating the architecture of sleep - NREM → REM sleep cycle is around 90 (ninety) minutes in humans - More deep NREM (slow wave sleep) early in sleep, more REM sleep late in sleep - Appearance: 1) Awake a) Eyes: open with blinks b) BrainWaves: i) High frequency (fast 15-30 times/sec or 15-30Hz) ii) Low amplitude (small) iii) desynchronized c) Muscle: strong muscle tone 2) Stage 2 NREM (SLEEP SPINDLES AND K COMPLEXES → MEMORY CONSOLIDATION) a) Eyes: eye movements stop (slowly roll in Stage-1 NREM) b) Brain waves: i) Slow frequency (slower 6-10 times/sec or 6-10Hz) ii) Higher amplitude (larger) iii) More synchronous iv) Special events: K-complex and Sleep Spindles Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 c) Muscle: lowered muscle tone (dramatic reduction) 3) Stage 3 + 4 NREM (Slow wave sleep) a) Eyes: no eye movements (contamination from EEG) → Right/lower graph for EEG is much more scattered than higher b) Brain Waves i) Very slow frequency ii) Slow 1-4 times/sec or 1-4Hz iii) View high amplitude iv) Synchronous brain waves c) Limited muscle tone 4) REM sleep a) Eyes closed but horizontal movements: back and forth → look sort of like blinks b) Brain Waves i) Higher frequency (fast more than 10 times/sec or 10 Hz) ii) Low amplitude (small) iii) Muscles → atonia: no muscle tone iv) Desynchronized (like awake) Discussion 1 - Polysomnography: EEG (brain) + EOG(eyes)+ EMG (muscle) - X axis → time - Y axis → amplitude - Power: amplitude integrated across time - More power/higher amplitude → more activity/energy in that channel or frequency - Stage 4 SWS sleep - The left and right channels move in parallel, so you know it is not true REM sleep - normally , the channels show opposite polarity, with one eye going up and the other going down - Also EEG channels represent synchronized brain activity of NREM sleep (delta and slow waves) Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Young people have large amplitude slow waves than older adults - REM sleep - Phasic rem: eye movements that come in phasic bursts - Tonic rem: no eye movements - Notice that the two eye channels go in opposite directions for true eye movements - The EEG: 1) low amplitude 2) high frequency activity 3) more similar to wakefulness than to NREM sleep - The EMG is characterized by extremely low or no muscle activity, lower than any other stage - The eyes and brain tell you that it is not NREM sleep, and the muscle activity tells you that it is not wake - Stage 2 sleep - There are no eye movements - The EEG activity is faster than N3 and N4 Slow wave sleep, bt is slower than wake/Rem sleep - Stage 2 is characterized by the presence of two oscillatory events: the sleep spindle and the K complex - Circadian rhythms: biological rhythms that occur in 24 hour cycles - Sleep is circadian → sleep at night, awake at day - Diurnal: sleeping at night and being awake at day - Nocturnal: sleeping at day and being awake at night - Crepuscular: animals that are awake during twilight, like fireflies - Ultradian: cycle faster than 24 hours, such as cycles within the sleeping cycle - Infradian: cycle slower than 24 hours, such as the menstrual cycle - An organism must compensate for a drastic difference between night and day, so circadian rhythms are to deal with this Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Example: camping in a dessert - Advantages of rhythm: 1) Synchronize bodily functions 2) Avoid predation 3) Awake when food is available 4) Occupy a temporal niche, save energy - Zeitgebers: external (exogenous) time giver that synchronizes master suprachiasmatic nucleus(SCN) and peripheral body clocks for optimal efficiency and coordination of body-brain processes 1) Light 2) Food: important for peripheral clocks in the liver and pancreas 3) Exercise and activity: used in eldery to strengthen their circadian rhythm, which deteriorates with age, help recover from jet lag and shift work faster - endogenous rhythm (without zeitgebers) is roughly 24 hours - Melatonin → can phase-advance internal clock - Jet lag: Sleepiness during day + sleeplessness at nights - Circadian disruption: cognitive deficits - Flight attendants on short recovery crew had 1) smaller right temporal volume 2) Increased cortisol levels 3) Slower reactions times and less accuracy on computer visual-spatial task - Short recovery was less than 5 days for transmeridian flights that fly across 7 time zones, while the others had 14 days - Sleep deprivation is a likely carcinogen - Circadian rhythm and medicine - Blood pressure medications are most effective if taken between 6am-12am because blood pressure is highest - Cancer treatments are also more effective at certain times of day - Cancer drugs are have sweet spot or being most effective and least toxic - Sleep is controlled by circadian and homeostatic processes - Two process Model: 1) Process S: represents sleep debt, increases during wake and declines during sleep → Adenosine a) NREM > REM → at the start of sleep there is more NREM than REM b) Process S favors NREM sleep c) After night of sleep deprivation, S continues to build and leads to longer total sleep time and more NREM sleep Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 d) Process S regulates NREM and it is the priority stage of sleep 2) Process C: represents internal processes regulating alertness and arousal, governed by circadian clocks → Melatonin a) NREM < REM → at the end of sleep there is more REM than NREM b) REM is more under control of Process C, but it still has a homeostatic component c) REM rebound: an increase in REM after >1 night without REM sleep, view sleep restriction, drugs, etc d) Controlled by the SCN - Sleep timing and stage are controlled by circadian and homeostatic processes - Two processes model not only explains the onset and offset - A night of sleep deprivation increases sleep pressure, leading to: 1) Daytime sleepiness 2) Increased NREM and total sleep time at next sleep opportunity Lecture 3: Circadian Rhythms - Circadian Rhythms: rhythm with an approximately 24hr cycle length that are endogenous in origin (meaning generated from within the body) - Zeitgebers are exogenous → generated outside of body and sync SCN and other Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 biological clocks - What circadian rhythms control: 1) help regulate the sleep/wake cycle 2) Regulate eating, drinking, body temperature, and hormone release (urine volume and birth and deaths) - Every living species shows a 24hr circadian rhythm - Why we have circadian rhythm: circadian rhythm allow living species to synchronize (behavior and internal biology) with the 24hr light/dark rotation of the earth - First demonstration - Jean Jacue d’Orto de Mairan (1729): french geophysicist - Studied leaf movements of a heliotrope plant across the 24 hr period (Darwin called them “Sleeping Leaves”) - Discovered the persistence of circadian rhythms in absence of external cues (light) - Sleep exists in all animals regardless of evolution, but only birds and mammals have full blown REM sleep - REM is newer form of evolution - REM sleep evolves twice independently, once when seperating into birds, and secondly when going into mammals - This fact tells two things 1) Relative to fish/amphibians, we can regulate our body temp, so perhaps the evolutionary pressure to create rem sleep came from need of thermoregulation so perhaps rem is related to thermoregulation 2) Metabolic regulation is perhaps related as thermoregulation is connected (more metabolic is more heat) so perhaps REM has to do with thermoregulation - First demonstration in humans - 1938: Kleitman and Richardson spent six weeks in Mammoth Cave, Kentucky (world’s longest cave) (first to demonstrate the rhythm is endogenous) - At the time, some scientists believed our sleep/wake rhythm was controlled by sunlight - Examined what happened to their sleep/wake schedule in the total absence of light - Richardson (younger) developed a 24hr day (between 26-28hr/day) with 9hr sleep periods - Kleitman (older) had a harder adjusting and stuck close to 24 hr - Take home: human circadian clock generates a rhythm slightly longer than 24 hours when it has no external cue to set it Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Current estimate of circadian rhythm is 24hr 10 min for most humans - Mean rectal temperature across 24 hr: body temperature reaches its low for the day about 2 hours after sleep onset and reaches its peak about 6 hours before sleep onset - - Rhythms of Waking and Sleep - The master 24hr (circadian) clock regulating biological rhythms is the suprachiasmatic nucleus (SCN): part of the hypothalamus and regulates wake and sleep by controlling levels of activity in the brain and the body - Uses melatonin (“Darkness Hormone”) from the pineal gland - It needs resetting everyday and this has to be done through zeitgebers - Melatonin: chemical messenger used by the SCN released from the pineal gland of the circadian rhythm, including the timing of our wake-sleep rhythm - Normally light hits the brain and melatonin is not released, but the moment it stops hitting it, the melatonin increases - Melatonin secretion usually begins around two hours before bed - It cannot be released in light, only released in darkness - It remains high across the night and is suppressed during the day - Rhythms of waking and sleep - Since the endogenous (self-paced) biological clock is imperfect (24hr 10 min in humans), it needs to be reset to precisely 24 hrs - Zeitgeber: any stimulus that resets our daily circadian rhythm to precisely 24 hr - Light is the most important zeitgeber because it is the most reliable twenty four hour signal - Disrupting the circadian rhythm 1) Jet lag: due to crossing time zones ,caused by a mismatch between the internal circadian clock and external time (in the new time zone) Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 a) jet engines transport you through time zones much faster than our circadian rhythm can keep up with b) Characterized by sleepiness, during the day, sleeplessness at night c) Example: New York to London: when you fall asleep on the plane, you are woken when it is the morning destination in London, it is still 2 AM back in NYC d) For every hour that you shift out of your timezone, it takes about one day to readjust (NYC to London → 5 hr difference, so 5 days to adjust) 2) Melatonin pills: can phase-advance the internal clock (like winding a clock forward) helping you sleep in the new time zone at night) a) Secretion usually begins 2-3hr before bed b) Melatonin impacts the brain and body, including feedback to reset the sleep wake rhythms through effect on the SCN suprachiasmatic nucleus - Two process model of sleep-wake regulation - Circadian factor process (Process C): first of two governing sleep-wake rhythms - As the circadian rhythm increases, our drive to be awake increases and vice versa Lecture 4: Phylogeny - Insects: 1) Phenomenology: cannot be tracked in insects 2) Behavior: (Dr. E. Rhoschild) a) Circadian timing —> awake during the day, not night b) Horizontal position c) Low muscle tone d) Non-response (but reversible) - Birds: 1) Birds have physiologically confirmed cycles of NREM and REM sleep 2) Unlike mammals, short cycles: a) NREM sleep episodes: around 2.5 minutes b) REM sleep episodes: around 8 seconds 3) Most birds do not lose muscle tone during REM sleep as consistently as mammals do 4) Birds have unihemispheric sleep: can sleep with halves the brain, with one half of the brain can sleep while the other half stays awake a) This only happens for NREM sleep (but both sides can also have NREM) b) Both halves of the brain sleep during REM, never one side alone Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 c) Can be: awake/awake, awake/NREM, NREM/NREM, REM/REM, NREM/REM i) 2nd option is unique to birds 5) White crowned sparrow: military is looking to see if there are ways to skip sleep using this bird - Reptiles, Amphibians and Fish 1) Amphibians, fish, reptiles show deep brain electrical activity indicative of NREM sleep → difficult to equate to birds and mammals a) Birds when having SWS will still have open eyes on that side, but will be closed 2) Most studies failed to find REM sleep in Amphibians and Fish 3) Arguable REM-like activity in reptiles, but this remains debated - Birds and mammals, that have REM sleep, evolved separately from reptiles - Thus REM sleep evolved twice in evolution: once in birds, and once in mammals - This means NREM sleep is the original stage of sleep - REM sleep came later in evolution - Clues as to the function of REM - Thermoregulation: Birds and mammals regulate body temperatures differently than reptiles - Metabolic regulation: Birds and mammals do this by increasing their metabolic rate to maintain a constant body temperature in the cold, but reptiles cannot, potentially showing that reptiles diverged at a different time - How should humans be sleeping: - The !Kung - Sleep on the ground or hard pallets - No pillows - Collective sleeping - Minimal bedding avoids insects - Frequently take afternoon naps, especially during dry, hot season - Monophasic or Biphasic: - Most pre-industrial hunter-gatherer tribes: - 30-60 min afternoon naps Biologically hardwired dip in alertness in the middle of the day in all humans - Are Western cultures returning to this pattern? Nap pods Lecture 5: Brain Mechanisms → Awake, NREM and REM - Neurochemistry: substance - Three critical neurotransmitters for controlling sleep: 1) Acetylcholine (Ach) 2) Noradrenaline (NA) Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 3) Serotonin (5-HT) - Neuromodulators for sleep all come from the brain stem - Distribution comes from brainstem, the activating center - The Neurochemistry of Wake-Sleep Cycle - Active wake: a lot of serotonin/noradrenaline and a lot of acetylcholine is being produced - Quiet Wake: serotonin/noradrenaline and acetylcholine both being produced - NREM: serotonin/noradrenaline is being produced, while acetylcholine is not - REM: almost no serotonin/noradrenaline release, while a lot of acetylcholine is produced - Neurophysiology : 1) Cortex: Information Processing/Perception a) Slow wave activity is when cortex goes into wave function 2) Thalamus: Information gate “awareness switch” only active when high acetylcholine a) Sensory information enters the thalamus to create hearing, sight, touch, taste, and smell b) When stimulated, it is perceiving world and is alert during wakefulness c) When asleep, it turns off and there is no sensory information d) When in REM, arch increases and thalamus is turned on again and we begin understanding internal info 3) Brainstem: Activating center “power station” - AWAKE physiology → Information processing in awake: 1) Brainstem turns on electrical brain power → sensory processing begins 2) Information flood into brain from eyes, ears, nose, etc. activating the thalamus 3) Information reaches cortex, which leads to aroused and attentive state (wakefulness) - NREM physiology: 1) Brainstem turns off electrical brain power a) NA and 5HT shutdown 2) Thalamus gate is closed thus information cannot enter brain a) No sensory signal do not get past cortex does no processing 3) Asleep when there is no information feed to the cortex → firing is slow and synchronized with default activity only (no active processing) - REM physiology: Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 1) Brainstem partly turns on power (ACh) 2) Internal stimulation of the sensory gate (thalamus) 3) Memories, emotions, visual center and motor, and motivations are activated in the cortex to lead to dreaming 4) Prefrontal cortex is shut off, and the brain moves into being illogical, explaining state of dreaming a) PGO waves present caused by bursts of electrical activity - Functional anatomy (brain activation): - Ways to measure using brain scanners: 1) Positron emission tomography (PET) 2) Functional magnetic resonance imaging (fMRI) - Parts of brain in REM sleep: 1) Cingulate cortex: Emotional regulation 2) Motor cortex: movement initiation (m1) 3) Lateral prefrontal cortex: logical reasoning → deactivated during sleep! 4) Occipital Cortex: Complex visual processing 5) Hippocampus: memory - Visual, memory-filled motoric, emotional brain, without logical reasoning Discussion 2: - Chronotype MEQ scores (Morningness-Eveningness Questionnaire) - As we age, our chronotype tends to get earlier - Causal-mechanistic explanation: age related changes in the brain may alter circadian rhythmicity as well as social expectations - Strength of zeitgebers can influence variation within and across environments - Environment affects sleeping patterns - Sentinel Hypothesis: evolutionary explanation in variation in human chronotype - Seen in modern hunter-gatherer peoples of Hadza in Tanzania - a synchrony of activity levels is produced by chronotype variation and this chronotype variation covaries with age - Awake at any given time makes the individual sentinel against predators - Guarantees presence of sentinel at any given time? - Seehagen et al. 2014: Naps enhance memories in infants - Previous studies found that a full night of sleep can improve memory for recently acquired information - Experimental Questions: 1) Do daytime naps improve 6 and 12 month old infants’ memory? 2) Does memory improvement from a nap persist after 24 hours? Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Methods - Infants were assigned to: 1) Baseline a) Nap b) No nap 2) learning a) Nap b) No nap - The memory task was an imitation task were the infants watched a puppet perform 3 actions and then were given the puppet - Memory was scored based on the number of puppet actions repeated by the infant (out of 3) - Results: 1) Only infants who napped showed significant learning 2) Infants remembered more than 24 hours later if they napped after learning 3) Both no nap and nap groups had sleep, but the nap group had a sleep episode very soon after the learning episode, which gave the greatest memory benefit - Kurdziel et al. 2013: What is it about sleep during naps that enhances memory in children - Preschool children 3-5 years old were given a spatial declarative memory task (remember where on a grid an object is located) - Groups 1) napped 2) awake 3) napped with PSG - After an afternoon nap, children who had napped performed better than children who had not napped - Immediate is baseline → pre-nap, right after encoding - delayed → right after the nap - 24 hours is after a night of sleep (next day) - This difference persisted after 24 hours, meaning a normal night of sleep does not “even out” differences - The PSG was measured with children during the afternoon nap session Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Sleep spindles and memory enhancement → NREM spindle density was positively correlated with change in recall auracy - the more spindles, the greater the improvement during post-nap test - Sleep spindles may act like a file transfer mechanism that help with memory saving function - Lemos et al. 2014: Can naps enhance learning at school? - Questions: 1) Does napping also benefit middle school students? 2) Can naps enhance memory at school? - Students received a test in a subject they knew nothing about, they then heard a lecture on the subject - Students were either assigned to take a 2 hour nap condition or a normal class - Tested twice, pretest before lecture and a test 1, 2, or 5 days after lecture - Lecture was 15 minutes long and was about “vision and memory” - Students were all at schools in Brazil - They were not aware they would be tested later in the week - The nap condition was defined by having a 2 hour opportunity to nap, but the researcher did not verify that the students had napped - Naps improve memory - Graphs show each time point (N) and the % change in test score - Students remembered information one day later, regardless of whether they had napped or not (about even) - Students tested after 2 and 5 days only did significantly better if they had taken a nap after the lecture - At 5 days, performance for non-nap students was at the same level as before the lecture, with an 83% decrease 1 day post lecture - The results suggest that daytime napping can enhance learning at school - The students who napped after the lecture had memory that persisted for several days after the lecture - Specifically, the nap after learning protected the information learned from forgetting over the course of 5 days - Both groups learned the information, but only the non-nap group forgot most of it Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Ontogeny: sleep changes drastically across the lifespan in numerous ways - WAKE:NREM:Ratio also change 1) Childhood: ???? vs Adult: 4NREM: 1 REM (stable ratio for rest of life) 2) As older, amount of total sleep decreases 3) Children have more deeper deep rem sleep and will wake up fewer times in the night 4) Pattern of sleep being as high polyphasic with large amounts → monophasic with less as we get older - Exam: Look at hypnograph what age do you think the person will be Lecture 6: Circadian Rhythms and Sleep Ontogeny - Two process model of sleep-wake regulation - This circadian factor or “process (Process C): circadian rhythm which is our drive to be awake - As the circadian rhythm increases, our drive to be awake increases - - Two process model of sleep-wake regulation - process S: the amount of elapsed time since being awake and the drive to sleep, caused by adenosine build up - The longer you’re awake, the more pressure there is to sleep - When we sleep, we dissipate adenosine (decreasing sleep pressure/process S) - Adenosine decreases as we sleep and returns to S - Caffeine blocks/masks the signal of adenosine and fools your brain into thinking you’ve been awake for as long as you have through masking - When caffeine is metabolized, it all hits at once - The greater the urge to sleep is the greatest distance there is between the process of S and the process of C Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - - In sleep deprivation 1) you feel bad at 4-5 am, because of process C is at it lowest and Process C is high 2) You feel better at around 11Am due to Process C 3) Feel bad at 11PM due to large gap between Process C and S and leads to oversleeping next day and return of S to baseline - Process S could go on building forever - Sleep Ontogeny - Different sleep pattern in stage of life: 1) New born: highly polyphasic → no structure of day and night 2) 1 year old: polyphasic sleep 3) 4 year old: biphasic sleep 4) 10 years old: monophasic sleep 5) Adult: monophasic sleep, but shorter sleep period - Wake:REM:NREM ration changes - 20-90 years old: decreasing total sleep (40-50 years), stable of 4NREM1:REM ratio - As infant, 1:1 REM:NREM, 8 hours of each - 1-2 years: total NREM increases, while REM decreases - 2-20 decrease in total sleep - Sleep architecture changes - Child (~7 years) 1) Greater slow wave sleep 2) Few if any awakening 3) Somewhat more REM Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Young Adults (~25 years) - - Mostly deep sleep/NREM in first half of night, then mostly REM in second - Eldery (~75 years) 1) Absence of slow wave sleep 2) Increased awakening 3) Reduced REM Lecture 7: Creativity - Societal Anecdotes - The song yesterday came from to Mccartney when he was asleep - Thomas Edison: inventor - Thomas was a habitual napper, and had nap cots - Used sleep as a creativity tool - The genius gap: diet dreams Downloaded by Hanna Shpachenko ([email protected])  lOMoARcPSD|17698592 - Examples in science - Mendeleev - Empirical, scientific studies - Numeric number reduction task: Tested if people could see trend in number strings and had to find a rule that let you find it faster - REM sleep or dream sleep tends to gift these types of benefits - Never told to stay awake on a problem, instead sleep on it - Power of sleep transcends cultural boundaries → idioms - There is a 3 fold increase in problem solving Downloaded by Hanna Shpachenko ([email protected])