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Chapter 5

PSY100Y5 Chapter Notes - Chapter 5: Disinhibition, Dream Interpretation, Sleep Spindle

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Ayesha Khan

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Notes From Reading
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.
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Notes From Reading
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
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