CONSCIOUSNESS: the subjective experience or awareness of internal and external events
Can measure with:
Use of senses
Brain activity – recall of pictures and sounds activated corresponding brain areas –
tie between internal activity and brain activity
Levels of Consciousness:
Differences rely on:
o Is there brain activity? (i.e. brain death)
o Sleep-wake cycles?
o Awareness/purposeful movement
Minimally conscious state:
o Brain activity
o Sleep-wake cycles
o Awareness
o Locked-in Syndrome: no movement but total awareness
Vegetative state:
o Brain activity
o Sleep-wake cycles
o No awareness/purposeful movement or communication
Disorders of Awareness:
Visual neglect: unaware of one side of space, damage to right parietal lobe ignore
left side of space
o Nothing wrong with vision, about spatial awareness
o If it accompanies a stroke, it will often go away
o Choose non-burning house but not sure why
Some unconscious awareness occurs even though there is no
explicit/conscious awareness of the left side
Blind sight: person experiences some blindness with some spared visual capacities
in the absence of visual awareness – damage in the visual cortex
o Detect but cannot see movement
Altered States of Consciousness:
SLEEP:
circadian rhythms – body temp rises and falls
Neural mechanisms: pineal gland is triggered by dark light and secretes melatonin
Stages of sleep:
o Beta Waves: alert, awake, low amplitude, high frequency
o Alpha Waves: drowsy/relaxed, amp and frequency are higher
o Theta Waves: Stage 1 sleep, frequency slows down but amplitude is higher
Stage 2 sleep – sleep spindles and K-complex keep us asleep
o Delta Waves: slow wave sleep, high amplitude, low frequency, stages 3&4
, o REM Sleep: most similar to awake activity – paradoxical sleep, difficult to
wake, 80% report dreaming, eyes move beneath eyelids
Typical night includes 4-5 cycles, deepest early in the night, REM sleep increases in
length and frequency as the night progresses
How much sleep do we need?
Less sleep across life time and smaller proportion of REM sleep
Infants: 50% of 16-hr sleep is REM sleep
Why do we sleep?
Repairing and restoring (body and brain)
Facilitate learning
Survival value – sleep when you see less outside
o Sleep deprivation: performance and learning takes a hit if you deprive stages
3/4 and takes a HUGE hit when you deprive REM sleep
Altered States of Consciousness: INDUCED:
Can measure with:
Use of senses
Brain activity – recall of pictures and sounds activated corresponding brain areas –
tie between internal activity and brain activity
Levels of Consciousness:
Differences rely on:
o Is there brain activity? (i.e. brain death)
o Sleep-wake cycles?
o Awareness/purposeful movement
Minimally conscious state:
o Brain activity
o Sleep-wake cycles
o Awareness
o Locked-in Syndrome: no movement but total awareness
Vegetative state:
o Brain activity
o Sleep-wake cycles
o No awareness/purposeful movement or communication
Disorders of Awareness:
Visual neglect: unaware of one side of space, damage to right parietal lobe ignore
left side of space
o Nothing wrong with vision, about spatial awareness
o If it accompanies a stroke, it will often go away
o Choose non-burning house but not sure why
Some unconscious awareness occurs even though there is no
explicit/conscious awareness of the left side
Blind sight: person experiences some blindness with some spared visual capacities
in the absence of visual awareness – damage in the visual cortex
o Detect but cannot see movement
Altered States of Consciousness:
SLEEP:
circadian rhythms – body temp rises and falls
Neural mechanisms: pineal gland is triggered by dark light and secretes melatonin
Stages of sleep:
o Beta Waves: alert, awake, low amplitude, high frequency
o Alpha Waves: drowsy/relaxed, amp and frequency are higher
o Theta Waves: Stage 1 sleep, frequency slows down but amplitude is higher
Stage 2 sleep – sleep spindles and K-complex keep us asleep
o Delta Waves: slow wave sleep, high amplitude, low frequency, stages 3&4
, o REM Sleep: most similar to awake activity – paradoxical sleep, difficult to
wake, 80% report dreaming, eyes move beneath eyelids
Typical night includes 4-5 cycles, deepest early in the night, REM sleep increases in
length and frequency as the night progresses
How much sleep do we need?
Less sleep across life time and smaller proportion of REM sleep
Infants: 50% of 16-hr sleep is REM sleep
Why do we sleep?
Repairing and restoring (body and brain)
Facilitate learning
Survival value – sleep when you see less outside
o Sleep deprivation: performance and learning takes a hit if you deprive stages
3/4 and takes a HUGE hit when you deprive REM sleep
Altered States of Consciousness: INDUCED:
