Ch.5 Variations in Consciousness
Narcolepsy – sleep disorder in which a person will often fall asleep uncontrollably during their everyday
routine
William Dement – only disorder to be known “due to a flaw in the primary sleep systems in the brain”
The Nature of Consciousness
Consciousness – awareness of internal and external stimuli
William James(1902) – continuous flow as the stream of consciousness
-some thoughts entering your stream of consciousness are the result of intention – seem to shift our
attention to things of importance or interest in our environment
Behaviour is result of conscious thought but conscious thought cause behaviour
Francis Crick – examined DNA, won nobel peace prize
Variations in Awareness and Control
Attention and conscious closely related but not identical
Consciousness seems intentional and designed to further specific goals or motivation – control what we
want to listen when professor talks – other thoughts seem to meander into our minds
Michael Kane – concept of restless or wandering mind
Mind Wandering – refers to people’s experience of task-unrelated thoughts – thoughts that are not
related to what they are intentionally trying to do at a given moment
Smallwood & Schooler – mind wandering might be less likely to occur if the task you are engaged in is
one that requires significant cognitive resources, that mind wandering is associated with less accurate
awareness of external information and that there may even be a connection between mind wandering
and creativity in some contexts
Controlled and automatic process
-controlled – judgements or thoughts that we exert some control over, that we intend to occur
-automatic – effects happen without our intentional control or effort
Malcolm Gladwell – implications of automatic processing for our thinking and behaviour
-blink – how quickly and effortlessly some of our judgements and choices seem to be made
Unconscious thought effects
Ap Dijksterhuis - theory of unconscious thought
-under some circumstances the quality of decisions made under conditions when individuals do not have
the opportunity to engage in conscious thought may sometimes be more accurate
-if ppl are distracted from ‘conscious deliberation’ some decision may actually be enhance, compared to
conditions under which ppl have ample opportunity for conscious deliberation
-attention is the key to distinguishing between conscious and unconscious thought processes
-‘conscious thought is thought with attention; unconscious thought is thought with attention
-Conscious thought – small subset of relevant info when deciding or evaluating – constrained by capacity
limitation
-unconsious though – doesn’t have same capacity constraints
Electroencephalograph – device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp
-summarizes rhythm of cortical activity in the brain in terms of line tracing call brain waves
-varies in amplitude(height) and frequency
-human brain waves is divided in 4 principal bands – beta(13-24cps), alpha(8-12), theta(4-7), delta(-4)
see figure 5.1 on page 202
Biological Rhythms and Sleep
Biological Rhythms – periodic fluctuations in physiological functioning
-organisms have internal ‘biological clocks’ that somehow monitor passage of time
-daily alternation of light and dark, change of seasons, phases of mood reflect this rhythm
The Role of Circadian Rhythms
Circadian Rhythms - 24hr biological cycles found in humans and many other species
-in humans, circadian rhythms are particularly influential in the regulation of sleep
-daily cycles also produce rhythmic variations(body temp – peaks in afternoon, reaches low point in
depths of night)
-individuals physiologically primed to fall asleep most easily at a particular time of the day
-‘night person’ ‘morning person’ reflect variations in circadian rhythms
Daily exposure to light readjusts ppls biological clocks
when exposed to light, receptors in retina send direct inputs to a small structure in hypothalamus
called Suprachiasmatic nucleus(SCN)
Ralph Mistlberger & Mary Harrington – SCN sends signals to pineal gland whose secretion of the
hormone melatonin plays a key role in adjusting biological clocks
Ignoring Circadian Rhythms
Sleep debt – if you lose sleep, must sleep extra to the amount of hours you were supposed to receive, hr
by hr
-if don’t sleep at usual time you go to sleep, quality of sleep isn’t great
Getting out of sync with circadian rhythms cause – jet lag
sleeping at wrong time because of the time zones “inferior sleep”
can make you feel fatigued, sluggish and irritable throughout the day
chronic jetlag – associated with measurable deficits in cognitive performance
to adjusts their biological clocks, it takes a day for each time zone crossed when you fly eastward and
two thirds of a day per time zone when you fly westward
Melatonin and Circadian Rhythms
melatonin – regulate human biological clock
-reduce effects of jet lag – helps travellers resynchronize biological clocks
-inconsistent results because timing of dose is crucial
The Sleep and Waking Cycle
Sleep is widely misunderstood - sleepers exp. Quite a bit of physical & mental activity as supposed to
being shut off Electromyograph (EMG) – records muscular activity and tension
Electrooculograph (EOG) – records eye movemnts
Cycling through the Stages of Sleep
Stages 1-4
amt of time it takes a person to sleep varies – how long it has been since person last slept, where
person is in circadian cycle, amt of noise or light in the sleep environment, and persons age, desire to fall
asleep, boredom lvl, among other things
Stage 1 - brief transition stage of light sleep that usually lasts only a few (1-7) min
-breathing and heart rate slow as muscle tension and body temperature decline
-hypnic jerks – brief muscle contractions occur as ppl fall asleep, generally occur during stage 1
drowsiness
-give lower frequency
stage 2- last 10-25 minns
-brief bursts of higher frequency brain waves called sleep splindles
-brain waves become higher in amplitude and slower in frequency, as body moves into a deeper form of
sleep called slow wave sleep
Slow-wave sleep (SWS)- consists of sleep stages 3 and 4 during which high amplitude, low-frequency
delta waves become prominent in EEG recordings
ppl reach SWS in about half an hr and stay in it for 30 mins
then reverses itself and sleeper gradually moves back upward through the lighter stages
REM sleep
-Reach stage 5 after reaching stage 1 again this is widely known as REM sleep
REM – rapid eye movements prominent during this stage of sleep
REM stage tends to be a ‘deep’ stage of sleep in which people are hard to be waken up
irregular breathing and pulse rate is marked in this stage
muscle tone is extremely relaxed so much that body looks paralyzed
EEG activity is dominated by high-frequency beta waves that resemble those observed when people
are alert and awake
Most dream reports come from REM, most vivid, frequent and memorable
Tore Nielsen – similarities and differences between REM dreaming and non-REM dreaming
Carlyle Smith – relationship between brain functioning in sleep and memory
brain activity acquired 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
different types of sleep are important for different types of learning
stage 2 – important for consolidation of procedural motor type task while REM sleep important for
complex logic type tasks
REM sleep - relatively deep stage of sleep marked by rapid eye movements, high frequency, low
amplitude brain waves and vivid dreaming
NON REM sleep - stage 1-4 marked by absence of Rapid eye movements, relatively little dreaming and
varied EEG activity Repeating the Cycle
-ppl repeat cycle four times
-cycle gradually changes, example, 1 REM last few minutes next one can last from 40-60 mins
NREM tends to get shorter and more shallow
-young adults spend 15-20% in slow wave and another 20-25% in REM
Age Trends In Sleep
Babies- only two types
-REM and Non REM
-sleep 6-8 times in a 24 hr period usually exceeding 16 hrs of sleep
-spend more time in REM stage than adults do, 50% of the time is in REM for babies
st
-REM gradually declines in babies, after 1 year it becomes 30% then until 20%
Adulthood- percentage of slow-wave sleep declines dramatically and % in stage 1 increases slightly
-sleeptime declines in advancing age until recently older ppl finding it hard to go to sleep and remain
-adults 60-80 less sleepiness during day than young adults 18-30, elderly may need less sleep than young
adults
-older ppl have more difficulty adapting to circadian phase shifts
-older age doesn’t necessarily affect poor sleep it is more due to health
Culture and sleep
-sleep does not appear to vary in different cultures
The Neural Bases of Sleep
Reticular Formation - brain structure important to sleep and wakefulness which is in core of brainstem
Ascending Reticular Activating System(ARAS) – consists of afferent fibres running through the reticular
formation that influence physiological arousal
-diffuses in many areas of cortex
-can be cut in the brainstem of a cat, it resulted in continuous sleep
-electrical stimulation along same pathway produces arousal and alertness
Other Brain Structures involved in regulation of sleeping and waking
Pons and adjacent areas in midbrain – critical to the generation of REM sleep
Medulla, thalamus, and basal forebrain – control of sleep and a variety of neurotransmitters involved
Doing without: Sleep Deprivation
Sleep Restriction
partial sleep deprivation and sleep restriction – ppl make do with substantially less sleep than normal
over a period of time
-effects depend on sleep lost and task on hand
negative effects most likely long lasting, difficult, and monotonous tasks or 5 hr sleep for many nights
-effects of sleep deprivation on our emotions and their regulations not only cognitive and performance
more emotional reactivity and less control in response to negative stimuli in the parts of the brain
implicated in emotional processing as a function of sleep deprivation – “emotional jello” Selective Deprivation
Awaken at REM stage – experience ‘rebound effect’ – spend more time in REM periods for one to three
nights to make up for their REM deprivation
-similar effects for slow wave sleep
ppl must have specific needs for REM and slow wave sleep and rather strong needs at that
Need for REM sleep and SWS – promote different types of memory
memory enhanced and reactivated during sleep
Memory consolidation – firming up learning throughout the day
REM sleep fosters the recently discovered process of neurogenesis
Neurogenesis- formation of new neurons – Contributes to learning which data links up with REM sleep
to memory c
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