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PSYC 1020H (99)
Chapter 5

Chapter 5- Body Rhythms & Mental States

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PSYC 1020H
Wolfgang Lehmann

Chapter 5- Body Rhythms & Mental States Biological Rhythms- The Tides of Experience  Consciousness- awareness of oneself and the environment  Biological rhythm- a periodic, more or less regular fluctuation in a biological system; may or may not have psychological implications  Entrainment- the synchronization of biological rhythms with external cues, such as fluctuations in daylight  Endogenous- generated from within rather than by external cues Circadian Rhythms  Circadian rhythm- a biological rhythm with a period (from peak to peak or trough or trough) of about 24 hours; from the Latin circa, “about”, and dies, “a day”  In the absence of external cues, we fall into day of 24.1-24.3 hours  Suprachiasmatic nucleus- an area of the brain containing a biological clock that governs circadian rhythms o The SCN is the main governor of circadian rhythms  Melatonin- a hormone, secreted by the pineal gland, that is involved in the regulation of daily biological (circadian) rhythms  Internal desynchronization- a state in which biological rhythms are not in phase (synchronized) with one another o Occurs when people take airplane flights across time zones- jet lag  Affects energy level, mental skills, and motor coordination o Occurs when a worker must adjust to a new shift- can cause accidents  Circadian rhythms are not perfectly regular in daily life, and differ greatly from individual to individual because of genetic differences Moods and Long-Term Rhythms  Seasonal affective disorder (SAD) o During the winter months, patients have feelings of sadness, lethargy, drowsiness and a craving for carbohydrates o About 2-3 % of Canadians suffer from SAD o Much more common among women than men o Use light therapy as a form of treatment  Menstrual cycle affecting moods? o Most people think so o Premenstrual syndrome (PMS) affects from 13% to “most women” o Many women do have physical symptoms, such as cramps, breast tenderness, and water retention o Emotional symptoms, especially irritability and depression, are rare o Fewer than 5% of all women have emotional symptoms predictably The Rhythms of Sleep The Realms of Sleep  Nathaniel Kleitman studied sleep- discovered rapid eye movement changed correlation with brain’s electrical activity  During sleep, periods of rapid eye movement (REM) alternate with periods of fewer eye movements, or non-REM (NREM) sleep, in a cycle that takes around 90 minutes  REM period lasts from a few minutes to an hour, on average 20 minutes  Rapid eye movement (REM) sleep- sleep periods characterized by eye movement, loss of muscle tone, and dreaming  When you first go to bed, brain emits alpha waves- regular, slow rhythm, high amplitude  Then you pass into sleep stages: o Stage 1- your brain waves become small and irregular, and you feel yourself drifting on the edge of consciousness, in a state of light sleep. If awakened, you may recall fantasies or a few visual images o Stage 2- your brain emits occasional short bursts of rapid, high-peaking waves called sleep spindles. Minor noises probably won’t disturb you. o Stage 3- In addition to the waves that are characteristic of stage 2, your brain occasionally emits delta waves, very slow waves with very high peaks. Your breathing and pulse have slowed down, your muscles are relaxed, and you are hard to rouse. o Stage 4- delta waves have now largely taken over, and you are in deep sleep. It will probably take vigorous shaking or a loud noise to awaken you. Oddly, though, if you walk or talk in your sleep, this is when you are likely to do so. No one yet knows what causes sleepwalking, which occurs more often in children than adults, but it seems to involve unusual patterns of delta-wave brain activity.  This sequence of stages take about 30 to 45 minutes, then move back up ladder from 4 to 1  70 to 90 minutes after onset of sleep, go to REM sleep o Heart rate increases, long bursts of very rapid, somewhat irregular brain waves, breathing faster and irregular, skeletal muscles go limp and are paralyzed o Vivid dreams most likely to occur Dreams reported when woken from REM 82% of time, non-REM 51% of time o Non-REM dreams shorter, less vivid and more realistic than REM, except in last hour of sleep o About 30% of population have awaked from REM sleep before muscle paralysis wears off, 5% have “waking dreams” o Reasons for REM sleep controversial Why We Sleep  Sleep allows rest period to eliminate waste from muscles, repair cells, conserve or replenish energy, strengthen immune system, recover abilities lost during day  When we don’t sleep enough, bodies operate abnormally o Hormones necessary for muscle development and immune system drop  Sleep is also necessary for normal mental functioning o Chronic sleep deprivation lowers cortisol, stress hormone  3.3 million Canadians (1/7 over 15) have chronic insomnia- trouble falling/staying asleep o From psychological or physical problems, and irregular/demanding schedules  Sleep apnea- a disorder in which breathing briefly stops during sleep, causing the person to choke and gasp and momentarily awaken  Narcolepsy- a sleep disorder involving sudden and unpredictable daytime attacks of sleepiness or lapses into REM sleep  REM behaviour disorder- a disorder in which the muscle paralysis that normally occurs during REM sleep is absent or incomplete, and the sleeper is able to act out his or her dreams  2/3 of North Americans don’t get recommended 7-8 hours of sleep, students only 6 o Most adults need more than six hours for optimal performance, adolescents 10  Drowsiness involved with 100,000 vehicle accidents a year  Sleep deprivation also linked to lower grades  Good night’s sleep promotes mental functioning o Students with 8 hours of sleep retained nonsense syllables better  Consolidation- a process by which the synaptic changes associated with recently stored memories become durable and stable, causing memory to become more reliable  Improvements in memory linked most closely with REM and slow-wave sleep (stages 3 and 4) for specific motor and perceptual skills  Emotional memories, recollection of events, locations and facts also strengthened in sleep  Possibly enhances problem solving, as it relies on information stored in memory  Researchers not unanimous on role of sleep in learning and memory o Some studies produced negative results Exploring the Dream World  Lucid dream- a dream in which the dreamer is aware of dreaming  For years, sleep researchers wondered if eye movements in REM sleep correspond with events and actions in a dream o Disagree on results  Why do we dream? Dreams as Unconscious Wishes  Sigmund Freud believed dreams were “a royal road to the unconscious” o Concluded that nighttime fantasies provide insight on desires, motives and conflicts of which we are unaware  Psychoanalytic approach- said we are able to express our unconscious wishes and desires, often sexual or violent in nature  Thoughts and objects are translated into symbolic images  Must distinguish between: o Manifest content, the aspects of it that we consciously experience during sleep and may remember upon waking o Latent content, the unconscious wishes and thoughts being expressed symbolically  Not everything is symbolic Dreams as Efforts to Deal with Problems  Dreams reflect ongoing conscious preoccupations of waking life o Relationships, work, health etc  Problem-focused approach, symbols and metaphors convey, rather than disguise, meaning of the dream  Supported by findings dreams more likely to contain material related to person’s current concerns than chance  Traumatic experiences also affect dreams  Some believe dreams reflect concerns and provide opportunities to resolve them Dreams as Thinking  Cognitive approach- emphasizes concern without solving problems o Dreaming modification of cognitive activity in waking  Construct simulations of real world, brain does similar work to awake o Difference in that no sensory input, feedback from world or bodily movement  Predicts if cut off from external stimulation while awake, mental activity would be like that in dreaming, with same hallucinatory quality  Predicts as cognitive abilities and brain connections mature in childhood, dreams change in nature, as they do o Children do not have true dream narratives until 7 or 8 o Young children dream infrequently, about bland, everyday things Dreams as Interpreted Brain Activity  Activation- synthesis theory- draws heavily on physiological research  Dreams result of neurons firing spontaneously in lower part of brain, pons, during REM  Dreams have no psychological meaning in themselves o Cortex tries to make sense by synthesizing, or integrating with existing knowledge and memories to produce interpretation, as in wakefulness Evaluating Dream Theories  Most psychologists accept that dreams have psychological meaning, but reject psychoanalytic interpretations- no empirical evidence, no rules for latent content  Believe problems occur in dreams, skeptics doubt ability to solve them in dreams  Activation-synthesis criticized- doesn’t account for dreaming outside of REM, not all dreams or disjointed and bizarre  Cognitive approach new, needs to be tested against neurological and cognitive
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