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Chapter 5

PSYCH Chapter 5.docx

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Ayesha Khan

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Chapter 5: Variations in Consciousness - Somniloquy – talking in your sleep - Consciousness is the awareness of internal and external stimuli - William James -> stream of consciousness - Francis Crick -> consciousness and its basis in neural cell assemblies - Neuronal correlates of consciousness (NCC) - Mind wandering – people’s experience of task-unrelated thoughts - 15-50% of people spend their time mind wandering - Smallwood and Schooler -> found that: - Mind wandering is less likely to occur if the task you are engaged in is one that requires significant cognitive resources - Mind wandering is associated with less accurate awareness of external information - Connection between mind wandering and creativity - Controlled (judgments, thoughts we have control over/intend to occur) and automatic processes (without our intentional control or effort) - Odor affected rating without the participants being aware of either the odors or their effects (implicit process) - Blink (Malcolm Gladwell) -> how quickly and effortlessly some of our judgments and choices seem to be made - Theory of unconscious thought -> if people are distracted or diverted from “conscious deliberation”, some decisions may actually be enhanced - Unconscious thought should be superior when making complex decisions - Conscious thought -> capacity limitations (you consider only a small subset of all the relevant information when making a decision or evaluation) - Consciousness arises from activity in distributed networks of neural pathways (NOT from any distinct structure in the brain) - Electroencephalograph (EEG) -> a device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp - -The EEG summarizes the rhythm of cortical activity in the brain in terms of brain waves (line tracings) - Brain waves vary in amplitude (height) and frequency (cycles per second [cps]) - Beta (13-24 cps) -> alertly engaged in problem solving - Alpha (8-12 cps) ->relaxed and resting - Theta (4-7 cps) -> light sleep - Delta (4 cps) -> deep sleep - Biological rhythms are periodic fluctuations in physiological functioning (internal biological clocks) - Circadian rhythms are the 24-hour biological cycles found in humans and many other species (ex: body temp. peaks during the afternoon and reaches its low at night) - Daily exposure to light readjusts people’s biological clocks - When exposed to light, some receptors in the retina send directs inputs to a small structure in the hypothalamus called the suprachiasmatic nucleus (SCN) - SCN sends signals to the nearby pineal gland (whose secretion of the hormone melatonin plays a key role in adjusting biological clocks) - Circadian rhythms in humans are regulated by multiple internal clocks, with a central pacemaker located in the SCN - Sleep loss must be paid back hour for hour - Ignoring circadian rhythms = jet lag (jet lag is associated with deficits in cognitive performance) - To compensate for jet lag -> a day for each time zone crossed when you fly east, and about two thirds of a day per time zone when you fly west - Ex: sports teams. Teams flying west perform better than teams flying east - The sleep lost when the clock is set ahead in the spring shift to Daylight savings time is associated with an increase in traffic accidents during the week after the switch - Melatonin helps jet lag, but timing of the dose is crucial (its easy to get it wrong) - Exposure to bright lights can help realign the circadian rhythms of rotating shift workers - Electroomyograph (EMG) records muscular activity and tension - Electrooculograph (EOG) records eye movements - During sleep -> 5 stages - Stage 1 -> light sleep, lasts a few minutes (1-7 mins.), slow breathing and heart rate, muscle tension and body temperature decline, hypnic jerks (brief muscular contractions that occur as people fall asleep) - Stage 2 -> lasts 10-25 minutes, brief bursts of sleep spindles (higher frequency brain waves), brain waves become higher in amplitude and slower in frequence - Stages 3&4 -> Slow Wave Sleep (SWS), high-amplitude, low-frequency delta waves become prominent. - Individuals reach SWS in half an hour, and stay there for half an hour - Then the cycle reverses itself, you move back upward through the lighter stages - 5 stage -> when you should reach “stage 1” AGAIN, called REM (rapid eye movements) sleep - REM sleep -> irregular breathing and pulse rate, muscle tone is relaxed, minimal body movements (“paralyzed”), deep stage of sleep BUT dominated by high-frequency beta waves - REM dreams are more frequent, vivid and memorable - Carlyle Smith -> brain activity during sleep is central to consolidation of information acquired during the day & different stages of sleep may be implicated in memory for different types of tasks of information (ex: stage 2, important for procedural motor-type tasks, REM sleep important for complex logic-type tasks) - Non-REM sleep ->stages 1-4, relatively little dreaming, varied EEG activity - One night, repeat the sleep cycle about 4 times - The first REM period is short (lasts only a couple minutes) - Subsequent REM periods get progressively longer (peaking at around 40-60 minutes) - Non REM intervals tend to get shorter, more shallow - These trends = most SWS occurs early in the sleep cycle & REM sleep tends to pile up in the second half of the sleep cycle - 15-20% of time spent in SWS, 20-25% in REM sleep - This all differs across people - Sleep cycle of babies: only REM (accounts for 50% of their sleep for the first couple months, but then declines to 30%) and non REM sleep, get 16 hours of sleep a day usually - Increased frequency of nighttime awakening seen among the elderly - Co-sleeping (children and parents sleeping together) discouraged in Western society but practiced in the Japanese culture - “Siesta cultures” in tropical regions, ppl have midday naps to avoid working during the hottest part of the day - Reticular formation (in the core of the brainstem) -> brain structure that is important to seep and wakefulness - Ascending reticular activating system (ARAS) consists of the afferent fibres running through the reticular formation that influence physiological arousal - The ARAS projects diffusely into many areas of the cortex, produces arousal and alertness - Activity in the pons & adjacent areas in the midbrain is critical to the generation of REM sleep - Various areas in the hypothalamus are important for the regulation of sleep and wakefulness - The medulla, thalamus, and basal forebrain are noted in the control of sleep, and a variety of neurotransmitters are involved - A constellation of brain structures and neurotransmitters contribute to regulation of the sleep and waking cycle - Effects of sleep deprivation: performance and cognitive deficits, emotions&their regulation - “Rebound effect” -> spend extra time in REM Periods for one to three nights to make up for their REM deprivation - Importance of REM and SWS: contribute to firming up learning that takes place during the day, promote different types of memory - Sleep may foster creative insights the next morning related to the previous day’s learning - Neurogenesis -> formation of new neurons - The hippocampus is critical in the formation of memories - The adult hippocampus produces a lot of new neurons - Adult neurogenesis facilitates learning and memory processes related to hippocampal functions - Sleep loss affects physiological processes which affects physical health (ex: sleep loss triggers hormonal changes that increase hunger) - Sleep loss leads to impaired immune system functioning and increased inflammatory responses - People who sleep less than 7 hours OR sleep MORE than 8 hours have a higher mortality risk - Mortality rates are especially high among those who sleep over 10 hours - There are 78 different types of sleep disorders - Insomnia -> chronic problems in getting adequate sleep - Occurs in three basic patterns 1) difficulty in falling asleep initially (common in younger people) 2) difficulty in remaining asleep (middle-aged and elderly) and 3) persistent early morning awakening (middle-aged and elderly) - Insomnia increases with age and more common in women - Pseudo-insomnia or sleep state misperception is when people THINK they are getting an inadequate amount of sleep - The discrepancy between individual’s feelings about how much they sleep and objective reality shows that states of consciousness are highly subjective - Causes of insomnia: anxiety, tension, emotional problems, back pain, ulcers, asthma, use of drugs (ex: stimulants like cocaine and amphetamines) and higher level of arousal - Treatment: benzodiazepine sedatives and nonbenzodiazepine sedatives - Sedatives can be a poor long-term solution - Side effects: feeling drowsy and sluggish the next day, becomes less effective with continued use so people increase their dose intake (vicious circle of dependence on sleeping pills), unpleasant withdrawal symptoms - Behavioral treatments/interventions (cognitive behavioral therapy [CBT]) produce more long-term benefits - Narcolepsy -> sudden and irresistible onsets of sleep during normal waking periods. - Goes DIRECTLY from wakefulness into REM sleep for a short period of time (10-20 minutes) - Victims fall asleep instantly, anywhere (ex: while driving) - Treated with stimulant drugs - Sleep apnea -> frequent, reflexive gasping for air that awakens a person and disrupts sleep (5 such events per hour of sleep) - Person stops breathing for a minimum of 10 seconds - Heart failure is prevalent among people with sleep apnea - Treated via lifestyle modifications (ex: weight loss), drug therapy, special masks/oral devices to improve air flow, or surgery - Nightmares -> anxiety-arousing dreams that lead to awakening, usually from REM sleep - Associated with measures of an individual’s well-being - Stress = higher frequency and intensity of nightmares - Night/sleep terrors -> abrupt awakenings from Non REM sleep, accompanied by intense autonomic arousal and feelings of panic - Produce accelerations of heart rate, occur during stage 4 - Victims (usually) let out a piercing cry, bolt upright, and then stare into space - They remember a simple, frightening image - Somnambulism/sleepwalking -> occurs when a person arises and wanders about while remaining asleep - Occurs during the first 2 hours of sleep (in SWS) - Episodes may last from 15 seconds to 30 minutes - Genetic predisposition - REM sleep behavior disorder (RBD) -> potentially troublesome dream enactments during REM periods - Talk, yell, gesture, flail about, or leap out of bed during their REM dreams - Dreams are mental experiences during REM sleep that have a story-like quality, include vivid visual imagery, are often bizarre, and are regarded as perceptually real by the dreamer - Unfold in familiar settings, with family, friends, colleagues - In our dreams we move through coherent sensible, realistic virtual worlds & usually from a 1 person perspective - Dreams ass
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