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Chapter 5

Textbook Chapter 5 Notes

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University of Toronto Mississauga
Ayesha Khan

Notes From Reading C HAPTER 5:V ARIATIONS INC ONSCIOUSNESS (P GS. 198-247) On The Nature of Consciousness  Consciousness is the awareness of internal and external stimuli and includes: o You’re awareness of external events o You’re awareness of internal sensations o You’re awareness of self as the unique being going through these experiences o Your awareness of your thoughts about these experiences Variations in Levels of Awareness  Conscious and Unconscious are different levels of awareness.  Mind Wandering – refers to people’s experience of task-unrelated thoughts Unconscious Thought Effects  Conscious constrained by capacity limitations such that you often consider only small subset of all relevant information when making decisions or evaluations  Research suggests that decisions made when people do not have the chance to make conscious deliberations may sometimes be more accurate Consciousness and Brain Activity  Electroencephalograph (EEG) – device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp. o i.e. Summarizes the rhythm of activity of the brain (brain waves).  4 Types of Brainwaves based on frequency – beta, alpha, theta, and delta  Variations in consciousness re correlated with variations in brain activity. Biological Rhythms and Sleep  Biological Rhythms – periodic fluctuations in physiological functioning (internal “biological clocks”) The Role of Circadian Rhythms  Circadian rhythms are the 24-hour biological cycles found in humans and many other species (influential in the regulation of sleep  When the retina is exposed to light, it sends direct inputs into the superchiasmatic nucleus (SCN) – the central pacemaker located in the hypothalamus Ignoring Circadian Rhythms  Quality of Sleep Suffers, where you become Fatigue, Sluggishness, and Irritability  Negative impact on productivity, accident proness, quality of work, social relations, and physical and mental health.  Poor sleep is associated with jet lag and rotating shift work is due to being out of sync with circadian rhythms Melatonin and Circadian Rhythms  Hormone Melatonin – regulates human bio clock. May be effective as a mild sedative, to treat insomnia.  Administration of melatonin, and exposure to bright light appear to have some value in efforts to realign circadian rhythms that are out of sync The Sleep and Waking Cycle  Electromyograph (EMG) – records muscular activity and tension  Electroculograph (EOG) – records eye movements Cycling Through the Stages of Sleep  Stage 1: a brief transitional stage of light sleep that lasts only a few minutes. o Breathing and heart rate slow, muscle tension and body temp go down. o Alpha Waves are replaced with theta waves and Hypnic jerks may occur.  Stages 2-4: respiration rate, heart rate, muscle tension, and body temp continue to fall. 1/5 Notes From Reading C HAPTER 5:V ARIATIONS IN C ONSCIOUSNESS (PGS . 198-247) o During Stage 2 (10 – 25 Min) brief bursts of higher frequency brain waves (“sleep spindles”) appear. o Brain waves slowly become higher in amplitude, but lower in frequency.  Slow Wave Sleep (SWS) – consists of sleep in stages 3 and 4, when high amp, low frequency delta waves become prominent in the EEG readings. (lasts 30 min)  REM Sleep – relatively deep stage of sleep marked by rapid eye movements, high frequency brain waves, and dreaming o Irregular breathing, muscle tone is relaxed. o EEG records beta waves, resembling if people were awake.  Non-Rem (NREM) consists of sleep stages 1-4, which are marked by absence of REM’s, little dreaming, and varied EEG activity. Repeating the Cycle  People usually repeat the sleep cycle 4 times during one night  First REM period is quite short ad then each subsequent REM period gets longer (peaking at 40-60 minutes in length) Age Trends in Sleep  Newborns will sleep 6-8 times in a 24-hour period for 16 hours (more spent in REM)  During adulthood, proportion of slow-wave sleep declines and the percentage of time spent in stage 1 increases.  Total Sleep increases with age in a substantial portion of older people. Culture And Sleep  Co Sleeping is the norm around most of the world.  Napping practices also vary where some cultures have a siesta during the day (adaptive) The Neural Bases of Sleep  Regulated by structures that lie deep within the brain  Ascending Reticular Activating System (ARAS) consists of the afferent fibers running through the reticular formation that influence physiological arousal. Doing Without Sleep: Sleep Deprivation  Partial Deprivation/Sleep Restriction o Occurs when people have less sleep than normal over a period of time o Negative effects are most likely when subjects are asked to work on long lasting, difficult, or monotonous tasks, or when repeatedly restricted to less than 5 hours of sleep o Common and can impair alertness and contributes to many accidents  Selective Deprivation o REM deprivation – little impact on daily functions, but on sleep patterns, as they shift to REM sleep quicker. o Selective deprivation of REM and slow-wave sleep leads to increased attempts to shift into these stages of sleep and increase time spent in these stages after sleep deprivation ends  Sleep Loss and Health o Link between lack of sleep and increased obesity o Short sleep duration is associated with a variety of health problems, but both short and long sleepers exhibit elevated mortality rates  Recent studies suggest that REM and slow-wave sleep help firm up learning that takes place during the day – a process called “memory consolidation” Problems in the Night: Sleep Disorders  Insomnia – chronic problem in getting enough sleep o Difficulty falling asleep, difficulty remaining asleep, and persistent early morning awakenings 2/5 Notes From Reading C HAPTER 5:V ARIATIONS IN C ONSCIOUSNESS (PGS . 198-247) o Insomnia is a fairly common sleep disorder and it has many diverse causes including the possibility that insomniacs have a higher arousal level o Increases with old age. o Sedative drugs are a poor long-term solution to insomnia because of the risk of overdose, escalating dependency, and carryover drowsiness  Narcolepsy – sudden and irresistible onsets of sleep during normal waking periods  Sleep Apnea – frequent, reflexive gasping for air that disrupts sleep  Nightmares – anxiety arousing dreams that lead to awakening, usually from REM sleep.  Night Terrors – abrupt awakenings from NREM sleep accompanied by intense arousal and feelings of panic. Usually a temp problem  Somnambulism (Sleep Walking) – when a person wanders about while asleep
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