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Biological Rhythms of Consciousness: Wakefulness and Sleep

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PSYC 100

Biological Rhythms of Consciousness: Wakefulness and Sleep Consciousness-person’s subjective awareness -includes thoughts, perceptions, experiences of the world, and self-awareness Dualism-philosophical belief that reality consists of two distinct entities: mind and matter (body) -Rene Descartes-> consciousness depends on a substance distinct from physical matter, since it doesn’t have properties that ascribe to matter -similar to religion Materialism-philosophical belief that reality can be known only through an understanding of the physical world which the mind is a part Physicalism- everything that exists is no more extensive than its physical properties Monism- only one kind of substance exists Global Workspace Theory of Consciousness-proposes that the brain’s working memory is a global workspace that serves to integrate access and coordinate the functioning of large numbers of specialized brain circuits-> the information in the global workspace is the information that we consciously experience -Bernard Baars -perceptual representations and memories compete for representation in the global workspace, the one that wins is more accessible by processes including memory, high-level decision making, and verbal report Neural Correlates- minimal neuronal mechanisms required to produce a specific conscious precept Blindsight- ability to interact behaviourally with objects while remaining consciously unaware of them Qualia-quality of a given perceptual experience -Quale: singular Consolidation-conversion of information from short-term memory to long-term memory Circadian Rhythms Biological Rhythms- organisms that are adapted in the cycles in the environment Circannual Rhythm- a yearly cycle Circadian Rhythms- internally driven daily cycles of approximately twenty-four hours affecting physiological and behavioural processes -changes with age -when people get older there is a change in when they prefer to sleep Suprachiasmatic Nucleus (SCN) -part of the hypothalamus -cells in the retina of the eye relay messages about light levels in the environment of it which causes it to communicate signals about light levels with the pineal gland -explains why humans sleep better when it’s dark outside Melatonin-a hormone released by the pineal gland -highest concentration at nighttime -reduced concentration during wakefulness Stages of Sleep Polysomnography-set of objective measurements used to examine physiological variables during sleep -thermometer to study body temperature -electrical sensors attached to the skin measures muscle activity around the eyes and other body parts -measures respiration -Electroncephalogram(EEG) -device that measures brain waves -sleep cycles are mostly defined by it -output is waves -waves described by: Frequency- number of up- down cycles every second Amplitude- height and depth of the up-down cycle Beta-Waves-characteristic of wakefulness -High-frequency -Low-amplitude -irregular nature reflects bursts of activity in different parts of the cortex, which signifies a person is alert Alpha Waves-waves are lower, larger, and more predictable -signals that a person may be daydreaming, mediating, or starting to fall asleep EEG Stages during sleep: 1.Theta Waves-brain waves slow down and become higher in amplitude-> -breathing, blood pressure, and heart rate decreases 2. Sleep Spindles and K Complexes periodic bursts of EEG activity 3. Delta Waves- brain waves slow down 4. Deepest sleep and the sleeper will be difficult to wake up 5. Slow-Wave Sleep-sleep other than REM sleep -regular, slow waves on an EEG -collectivity of stages 3 and 4 -fMRI shows the hippocampus is reactivated -stages reverse but doesn’t go back to stage 1, instead you go to REM sleep Non-REM Sleep (NREM) – the first four stages collectively REM Sleep-stage of sleep characterized by quickening brain waves, inhibited body movement, and Rapid Eye Movements (REM) -Sometimes known as Paradoxical Seep- because EEG waves seem to represent a state of wakefulness, even though you’re asleep -hippocampus shows elevated after doing brain activities -hippocampal activation correlates with recall in post-testing-> more active a person’s hippocampus is during sleep, the better they are in performing later memory tests REM Rebound-when we’re deprived of sleep -our brain spends an increased time in REM-phase sleep REM Atonia- lack of muscle response during dreams Parasomnia-sleeping disorder category involving abnormal movements, perceptions or dreams during any stage of sleep -REM behaviour disorder Theories of Sleep Restore and Repair Hypothesis-idea that the body needs to restore energy levels and repair any wear and tear on the body from the day’s activities -sleep deprivation shows that sleep is a physical and psychological necessity -lack of sleep leads to cognitive decline, emotional disturbances, and impairs functioning of the immune system -for some species, sleep deprivation can be fatal, even more than food deprivation Preserve and Protect Hypothesis-suggests that two more adaptive functions of sleep are preserving energy and protecting the organism from harm -for example, animals most vulnerable to predators sleep in safe hideaways during the day and humans and other visually oriented creatures sleep at night when it’s dark when we have a disadvantage Sleep Deprivation and Sleep Displacement Sleep Deprivation- occurs when an individual cannot or doesn’t sleep Sleep Displacement -occurs when an individual is prevented from sleeping at the normal time although they may sleep earlier or later than usual Jet Lag -discomfort a person feels when sleep cycles are out of synchronization with light and darkness Psychoanalytic Approach -Sigmund Freud -dreams are an unconscious expression of wish fulfillment -humans are motivated by primal urges, with sex and aggression being most dominant, and these urges cannot be expressed in reality, so they are expressed in our subconscious Manifest Content- images and storylines that we dream about Latent Content- actual symbolic meaning of a dream built on suppressed sexual and aggressive urges Dream Work- recording and interpreting dreams Activation-Synthesis Hypothesis -suggests that dreams arise from brain activity originating from bursts of excitatory messages from the brainstem, which produces the signs of eye movements and the EEG activity during REM sleep and activates perceptual areas of the brain producing imaginary sights and sounds and emotions -activation happens because of the brain stem -synthesis happens when the brain tries to make sense of things Problem-Solving Theory -Rosalind Cartwright -thoughts and concerns are continuous when awake to sleep, and dreams function find solutions to problems encountered while awake Insomnia -disorder characterized by an extreme lack of sleep Onset Insomnia- when a person has difficulty falling asleep Maintenance Insomnia- when an individual cannot easily return to sleep after waking in the night Terminal Insomnia-when a person wakes up to early and cannot go back to sleep -stems from internal sleep disturbances, rather than external factors such as an people talking Primary Insomnia-cases that arise from an internal source and not a result of another disorder Criteria: -person has at least one month of difficulty initiating or maintain sleep -sleep loss causes distress or impairment in social, occupational, and other areas -insomnia doesn’t occur during the course of some other sleep disorder or psychiatric disorder -sleep disturbance is not attributable to the effects of substance abuse Secondary Insomnia- result of other disorders, such as depression, physical problems such as recovery from surgery, or use of substances ranging from caffeine to illegal drugs Nightmares and Night Terrors Nightmares-particular vivid and disturbing dreams that occur during REM sleep -can be emotionally charged that cause the person to wake up -correlated with psychological distress-> relates to the problem-solving theory -not everyone recalls disturbing dreams Night Terrors-intense bouts of panic and arousal that awaken the individual, typically in a heightened emotional state -occurs during REM sleep -typically don’t recall any specific dream content -person experiencing it might scream, fight back against imaginary attackers, or leap and start to flee from bed before waking up -occurs most often in children experiencing stress Movement Disturbances Restless Legs Syndrome- persistent feeling of discomfort in the legs and the urge to continuously shift them into different positions -to sleep well, individuals need to remain still, during REM sleep the brain prevents movement by sending inhibitory signals down the spinal cord, however, a number of sleep disturbances involve movement and related sensations -people awake in the night to reposition legs, but they don’t remember waking up the next day Somnambulism-sleepwalking -disorder that involves wandering and performing other activities while asleep -happens more in childhood -people are not acting out dreams and doesn’t indicate any type of sleep or emotional disturbance, and they don’t remember doing it Sleep Apnea -disorder characterized by the temporary inability to breathe during sleep -various factors contribute to it, but most common in overweight and obese people -can be also caused by brain failure to regulate breathing which is caused by damage to or deterioration of the medulla of the brain stem, which is responsible for controlling the chest muscles during breathing -airway becomes physically obstructed anywhere from the back of the nose and mouth to the neck -treatment for mild apnea involves dental devices that hold the mouth in a specific position during sleep -Weight-loss efforts can accompany -in moderate to severe cases, a continuous positive airway pressure (CPAP) devices can be used to force air through the nose, keeping the airway open through increased air pressure -rarely fatal because breathing slowly or stopping causes oxygen levels in the blood to rapidly decline, causing a gasping reflex and resumed oxygen flow, which doesn’t cause people to wake up -people with it may not be aware of it, and is only recognized by a physician Narcolepsy -disorder where a person experiences extreme daytime sleepiness and even sleep attacks -goes from immediate waking to REM sleep, whereas normal sleep patterns causes people to go to REM stage after a while of sleep -people experience vivid dream-like images even if they are not fully asleep-> REM sleep involves dreaming Orexin-maintains wakefulness -people with narcolepsy have fewer brain cells that produce it, resulting in greater difficulty maintaining wakefulness Sleep Misperception Sleep State Misperception (SSM) -condition where a person underestimates the amount of sleep on a regular basis -people who have it are sometimes said to have Paradoxical Insomnia-> they believe they cannot sleep enough, but there is no physiological or medical evidence -no impairment of daily functioning Positive Sleep State Misperception-occurs when a person regularly overestimate their sleep -Shows signs of sleep deprivation- afternoon sleepiness and attention problems Overcoming Sleep Problems -cognitive and behavioural techniques-> drugs-> causes some people to become dependent on them-> many have showed the placebo-effect -food-> hard to sleep when you’re hungry -nightcap-> alcohol to induce sleep-> may cause sleepiness but it disrupts the quality of sleep, especially REM sleep, and may feel unrested the next day -psychological interventions-> sleep hygiene -keep clock out of sight because it causes pressure to sleep -avoid substances that disrupt sleep -schedule evening time to deal with stress -do something if you have trouble falling asleep, and return to bed when you’re about to fall asleep -get up at the same time every morning-> causes a daily rhythm -don’t pressure yourself to sleep -get exercise early-> causes you to be restless and aroused at bedtime if done late -use bed for sleeping not work or studying -if trouble sleeping repeats for weeks, see a sleep specialist to get tested for sleep apnea, restless leg syndrome, or other sleep problem that may require more specific interventions Altered States of Consciousness Hypnosis Hypnosis-procedure of inducing a heightened state of suggestibility -not trance which is portrayed in popular media -hypnotist suggests change and the subject is more likely to comply -Most effective if they are in one of the categories: -Ideomotor Suggestions- specific actions that could be performed -Challenge Suggestions- actions that aren’t to be performed, so the subject appears to lose the ability to perform an action
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