Sleep - Psychology



SleepSleep deprivation; Record for human staying awake: 11 days straight. Rats will die within 2 weeks from sleep deprivation. Adults need 7-9 hours to feel alert (college students need 9), but 60% get less than 6 hours. Can result in heart disease, diabetes, weight gain, lowered immune response, poorer concentration and learning ability, greater susceptibility to accidents, depression, and an elevated sympathetic nervous system response. A subset of the population needs 6 hours or less of sleep.We spend 1/3 of our lives in sleep.Sleep CyclesSleep cycles: stage 1-2-3-4-3-2-1-REMAlert state: beta waves at 13 waves/secondRelaxed state: alpha waves (8-12 cycles)Stage 1: Theta waves; 4-7 cycles/second; lasts up to 5 minutes; person may be confused, reports of ghosts most common here; may experience hallucinations (hypnogogic imagery). Hypnogogic sleep is halfway between sleep & wakefulness. Myoclonic jerk: between stages 1 and 2, the muscles jerk (brain notices between stage 1 and 2 that breathing & heart rate are slowing, so it sends out a burst of electrical activity to the muscles).Stage 2: Lasts about 20 minutes; periodic appearance of sleep spindles and K complexes (rapidly rising and falling brain waves). No eye movement here; deep muscle relaxation, body temp lowers, heart rate slows. Person is clearly asleep but can still be fairly easily awakened.Stage 3: transitional stage between stages 2 and 4; consists of 20% delta wavesStage 4 50% delta waves; deepest stage of sleep. Stages 3 and 4 are called delta wave or slow wave sleep and last 30 minutes or so. Hard to awaken. Bedwetting, sleepwalking, night terrors occur here. REM sleep: occurs about an hour after falling asleep. For about 10 minutes, your brain waves become fast and saw-toothed (almost like stage 1). Heart rate rises, breathing becomes fast and irregular, genitals become aroused, eyes dart around every 30 seconds or so. Paradoxical sleep: aroused on inside but paralyzed on the outside. Brain stem blocks motor messages so you can’t act out your dreams. REM behavior disorder: an abnormal condition occurring mostly in men over age 50 in which there is something wrong with the locus coruleus (the structure that keeps us paralyzed); here you act out your dreams (not paralyzed). Occurs in 1 in 200 people. REM sleep gets longer and longer as the night wears on, accounting for 20-25% of night’s sleep. If deprived of sleep for a few nights, you have REM rebound and experience intense dreams, even nightmares.DreamsOccur mainly during REM sleep, but we can also dream in other stages. REM dreaming differs from non-REM dreaming. REM dreams are more intense, vivid, plot-like, emotional, and illogical. Non-REM dreams are shorter, repetitive, more thoughtful & mundane; concerned with topics that we’re worried about (test, grocery list, etc)Dreams can be recalled more than 80% of the time if you’re awakened during REM. Visual and auditory centers of the brain are active when we’re dreaming but not during other stages of sleep.Questions about dreams:Does everyone dream? Yes, although not everyone recalls their dreams.How long do dreams last? They run on real time, and some can last an hour or two. The longer they seem, the longer they really last.Can external events become part of the dream? Yes. Dement & Wolpert (1958) sprayed water on sleepers in the REM stage. Most reported water in their dreams.When people can’t remember their dreams, does it mean they’re purposely forgetting them (repressing them)? No. No evidence of this.Do dreams foretell the future? No evidence of this.Do dreams express unconscious wishes? No evidence for this.Do blind people dream? Yes, but if they were blinded before age 4, they have no visual imagery in their dreams. They do have heightened other sense, though. If they were blinded after age 7, they do have visual imagery. The age between 4 and 7 appears to be a sensitive period for visual imagery development.Lucid dreaming: The ability to know we’re dreaming. Sometimes you can alter the course of a dream or wake yourself up. This is a part of lucid dreaming. Most frequent dream themes: (Domhoff, 2003)Being chased or pursuedBeing lost, late, or trappedFallingFlyingLosing valuable possessionsSexual dreamsExperiencing great natural beautyBeing naked or dressed oddlyInjury or illnessTheories about DreamsFreud’s psychoanalytic view: There is a manifest content (literal content) and a latent content (hidden meaning) of dreams. Dreams represent unconscious desires of impulses and can be interpreted to reveal a hidden meaning. Most have some sort of sexual meaning. No evidence for this.Activation-Synthesis Theory:Hobson and McCarley (1960s-70s) developed a theory that links dreams to brain activity. They said that dreams are just the brain’s attempt to make sense of random neural signals during REM sleep. REM is turned on by surges of acetylcholine, which activates nerve cells in the pons (brain stem). The activated pons sends messages to the lateral geniculate nucleus of the thalamus, which relays sensory information to the language and visual centers of the cortex. The cortex tries to weave a meaningful story from the random neural signals. The story is rarely coherent or logical because the neural signals are so random and chaotic. The amygdale is also ramped up, which adds emotion to the story (fear, anxiety, anger, sadness, and elation). The result is what we experience as a dream.Neurocognitive Theory:Proponents of neurocognitive views of dreaming argue that we can’t just look at dreams as a reflection of random neural activity. Instead, we must consider our cognitive capacities, which shape what we dream about. Children only recall 20-30% of their dreams before the age of 7 or 8. Their dreams are simple, lack movement, and are less emotional and bizarre than adult dreams are. Complex dreams are “cognitive achievements” that parallel the gradual development of visual imagination and other advanced cognitive activities. We begin to dream like adults when our brains develop the wiring to do so (Domhoff, 2001).Domhoff and others have found that many dreams are associated with emotional concerns and everyday preoccupations, and that dream content is surprisingly stable over long periods of time. There are cross-cultural similarities in what we dream. Virtually everyone experiences the following in dreams:More aggression than friendliness More negative than positive emotionsMore misfortune than good fortuneThe dreams of older adults resemble those of college students, but with age, negative emotions and aggression decrease.Women have more emotional content in their dreams, and their dream characters are more evenly divided between men and women.Men’s dream characters are more often men (by a 2:1 ratio; Hall, 1984).One cultural difference is that in technologically advanced societies, dreams feature fewer animals than in smaller, traditional societies.**Bottom line: Although dreams are often bizarre, they’re more consistent over time than we’d expect if they were just random neural impulses generated by the rmation-processing view: Dreams may help us sort out the day’s events by going over things we need to remember or think about. They may help fix our experiences in memory. Evidence: Babies spend 50% of their time in REM, compared to 20-25% of the time that older children and adults do. Babies have more to learn; everything is new to them. Babies who are brain damaged or developmentally delayed show less time in REM sleep, suggesting that REM sleep is a critical part of normal brain function.Function of dreamsThe function of dreams remains a puzzle because research evidence involving the role of learning and memory in dreams is mixed. Evidence from a variety of sources suggests the following:Dreams are involved in processing emotional memoriesIntegrating new experiencing with established memories to make sense of the worldLearning new strategies and ways of doing things (like playing pool or golf)Simulating threatening events so we can better cope with them in everyday lifeReorganizing and consolidating memoriesSleep disordersFatal familial insomnia: a rare brain disease in which patients lose the ability to fall asleep. It’s fatal within 6-30 months. Death results from multiple organ failure (thalamus degenerates, sympathetic nervous system becomes overactive, and person experiences weight loss, tremors, and endocrine system failure. May begin in late 30s but usually between the ages of 40-60. It runs in families. Four stages of FFI:Progressive insomnia, developing over about 4 months. Includes panic attacks and bizarre phobias.Second stage lasts 5 months or so and is marked by hallucinations, agitation, and sweating.3rd stage lasts 3 months—total insomnia and weight loss. Person looks like he’s aged significantly and may have incontinence.Last stage lasts 6 months and is characterized b y dementia. Patient becomes mute and dies.Insomnia:the most common sleep disorder, affecting 40% of adults occasionally and 10-15% chronically. Increases with age and is more common among women (maybe a hormonal or stress-related function). People with insomnia learn to fear their inability to fall asleep, and this gets them into a vicious cycle. Insomnia can involve the failure to fall asleep or stay asleep (or waking too early in the morning). Sometimes people who think they have insomnia actually don’t have it. They don’t know they’re asleep, or they simply don’t need as much sleep as others do. Two basic courses of treatment: medications (Ambien, Lunesta, Restoril, Sonata, Elavil, trazadone, etc.) and cognitive behavioral therapy. Medications are a good short-term fix but can cause dependence if used chronically. Cognitive-behavioral therapy is considered at least as effective as medication, probably more so. Basically, you have to learn not to fear insomnia and also replace your irrational thoughts about sleep with more rational ones. Gregg Jacobs, a national sleep expert, says the most important things to do are…Sleep restriction: don’t spend more than 7 hours in bed and don’t lie in bed on weekends for more than an hour past your normal wake-up time. Otherwise, you’ll mess up your sleep cycle. Also, avoid naps.Stimulus control: Don’t lie in bed more than 20 minutes trying to fall asleep. Get up and do something boring (read a textbook) in a quiet room until you feel sleepy. Otherwise, you’ll start associating your bed with the inability to get to sleep.Relaxation training: Rhythmic breathing, soothing visual imagery, etc. to help you get to sleep.These tips reduce falling asleep time from an average of 80 minutes to 19 minutes.Narcolepsy: a disorder in which sleep occurs at inappropriate and unexpected times. The person experiencing narcolepsy has sleep attacks lasting for a few minutes at random times; they fall immediately REM sleep. Cataplexy is a condition accompanying REM sleep in which the narcoleptic suddenly falls down as muscles become paralyzed (due to REM). Sometimes the person in a state of cataplexy is not actually asleep, just paralyzed. Narcolepsy seems to be related to the absence of a certain hormone called orexin, possibly as a result of damage from an overly-aggressive immune response. Narcoleptic attacks are often triggered by emotions, boredom, and heavy meals. Somnambulism: sleepwalking. Associated with slow-wave sleep and is most common in children (25% of all children experience it at least once).Night terrors: also occur in slow-wave sleep (usually the first stage 4 cycle of the night) and are common in children. It’s related to sleepwalking and seems to be an autonomic disturbance. In night terrors, people awaken from deep sleep with signs of intense arousal and powerful feelings of fear. They have no awareness of their surroundings and have no memory of it the next day. Nightmares, which are found in REM sleep only, are not associated with night terrors. Nightmares can be recalled, but night terrors cannot.Sleep apnea: an increasingly common condition affecting 1 in 25 people (usually overweight men, but it doesn’t have to be) in which one stops breathing during sleep. It causes multiple nighttime waking (several hundred times a day) as the person wakes and gasps for breath. It’s associated with a decrease in oxygen, which triggers waking. Caused either by the failure of the respiratory centers in the brain to maintain normal breathing or by the periodic collapse of the windpipe due to weight pressure. Can be treated with a CPAP machine or by surgery. ................
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