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Chapter 4

PSY100H1 Chapter Notes - Chapter 4: Sleep Deprivation

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Chapter 4
Neuronal workspace model
-conscious arises as a function of which brain regions are active
-relationship between consciousness and neural responses in brain
oimages with houses superimposed on faces
fusiform face area activated when saw face
temporal cortex regions associated with object recognition became active when saw
if one of these systems is damaged, then no output to consider and nothing is noted
as wrong e.g. hemineglect patients
does not include awareness of deficit
-importance of model: NO SINGLE AREA for general “awareness”
-consciousness viewed as mechanism that is actively “aware” of information, and serves the
role of prioritizing what info we need or want to deal with at the moment.
-People with hemineglect are not aware that part of their visual work is missing
-conscious experience of outside world turned off in sleep
-Invention of electroencephalogram (EEG), a machine that measures the electrical activity of the
nervous system, revealed brain working when asleep
-When awake: short, high frequency, desynchronized BETA waves
-When close eyes: brain activity slows down more synchronized, ALPHA waves
-Theta waves, easily aroused, geometric shapes, sensation of falling/limbs are jerking
-breathing regular, less sensitive, now REALLY asleep,
-Still theta waves, with occasional burst of activity known as sleep spindles and large waves
called K-complexes
oShutting out external world and keeping you asleep
oAbrupt noise trigger K complex
oAs you age, fewer sleep spindles, sleep more lightly
-insomnia: sleep disorder in which people’s mental health and ability to function compromised
by inability to sleep
Progression to DEEP sleep, next 2 stages
-delta waves, large and regular (called slow-wave sleep)
-hard to wake people up in slow-wave sleep, disoriented if do
-still process information in stage 4
oparents aroused by crying children but ignore traffic noise
omind continues to evaluate env for potential danger
After 90 MIN of sleep
-sleep cycle reverses
-returns to stage 3 and then stage 2
-flurry of beta waves, usually indicates alert, awake mind
-eyes start darting back and forth rapidly beneath closed eyelids
-REM sleep: rapid eye movements occur
-also called paradoxical sleep
-some brain neurons, especially in occipital cortex and brainstem, are more active in REM sleep
than when awake
-most muscles are paralyzed during REM
-at same time, body shows signs of arousal in genitals
-80% of time when people awakened during REM report dreaming compared to less than 50% of
time for non-REM
Cycle continues to repeat, progression from slow-wave sleep to REM sleep and back.
As morning approaches, sleep cycle shorter and more time spent in REM sleep.
People briefly awaken many times during night but don’t remember in morning.
Insomnia: a disorder characterized by an inability to sleep
Mircosleeps: brief, unintended sleep episodes, ranging from a few seconds to a minute, caused by
chronic sleep deprivation
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