Lec 6: Consciousness Flashcards
Consciousness
subjective experince of the world, resulting from brain activity
quality or state of being aware of an external object or something within itself
Awareness
state or ability to feel, to perceive or to be conscious of events
Persistent Vegetative state
Extreme state: full coma that lasts more than a month; Teri shiavo
Minimally conscious state
deliberate movement and communication are possible; erik ramsey
By using brain imaging/recording to examine the brain of a person in an apparent coma,
doctors can determine whether the patient is a candidate for treatement
locked in syndrome
all or nearly all of a person’s voluntary muscles are paralyzed, except for the eyes
are people suffering locked in syndrome conscious?
yes, they are aware and retain cognitive function
Jan Grzebski
In a minimally conscious state (due to a tumor near brain stem) for
19 years before he awoke and reported that he had in fact been
aware of events around him.
when the corpus callosum is removed
the two halves of the brain cannot receive info directly from each other aka split brain
with split brain
left hemisphere sees what’s happening on the right and right hemisphere sees what’s hapening on the left
interpreter
only for the left hemisphere; attempts to make sense of right hemisphere actions
sleep
although awareness of the outside world is turned down, EEG shows that the brain is still quite active in sleep
sleep serves two important biological purposes
restoration (physical health)
facilitation of learning (psychological health)
restorative theory and what is the evidence of that?
sleep allows the body to rest and repair itself
evidence
1) sleep increases after strenuous physical activity
2) growth hormones secreted in sleep
3) strengthens the immune system
effects of sleep deprivation
1) mood problems
2) decrements in cognitive performance such as attention and memory lapses
3) may compromise immune system
4) falling asleep for a few seconds to a minute aka microsleeps
Facilitation of Learning Theory
Sleep strengthens neural connections needed for learning to occur
Waves just before sleep
Alpha waves
neural oscillations are slowing down and you’re just barely falling asleep and might experience hallucinations
hypnic jerk
startled feeling when you’re about to fall asleep
feels like you’re falling which is due to muscle relaxation
Stage 1 of falling asleep
Theta waves which are higher but slower amp waves; it’s the brief transition between waking up and sleeping
someone at this stage may not have even known they had fallen asleep
Stage 2 of sleeping
Irregular waveforms
bursts in frequency (spindle) and amp (k-complex) of the wave forms
metabolism starts slowing down for about 20 minutes
Stage 3/4
Delta Waves aka slow wave slave; transition towards true ‘deep sleep’
allows brain and body to recover from a ‘hard day’s work’, also when hormones are distributed
difficult to wake someone up at this stage; less sensitive to external events; will be groggiest if woken up in this stage and have a long period of cognitive impairment
REM
Rapid eye movement
lightest phase of sleep and the amount of time spent in REM increases with each cycle
most dreaming occurs in REM sleep
REM and slow wave are important for learning to take place
students spend more time in REM during exam periods
paradoxical sleep
increased brain activity, but your muscles are very relaxed
sleep cycle
reverses after about 90 minutes with increasing frequency and decreasing depth (REM duration increases)
Dreams
products of an altered state of consciousness in which images and fantasies are confused with realtiy
Non-Rem dreames
dull; geneeral de-activation of many brain regions
REM dreams
more likely to be bizarre and include intense emotions, visual and auditory hallucinations, and uncritical acceptance of illogical events
brain structures associated with motivation, emotion, reward, vision are active, pre-frontal cortex is not
Freudian dream belief
dreams contain hidden content that represents unconscious conflicts
no scientific evidence that dreams represent hidden conflicts or for the special symbolic meaning of dream images
activation synthesis theory
brain tries to make sense of random brain activity that occurs during sleep by combining the activity with stored memories
evidence for A-S theory
emotion centers (limbic system) in the brain are active, explaining the intense emotions
frontal cortices aren’t active, explaining the uncritical acceptance of illogical events
evidence against A-S theory
dreams are not as chaotic as the activation-synthesis theory suggests
are often similar to “everyday life” walking experience
Threat Reversal theory
dreams sometimes simulate threatening events so that people can rehearse strategies for coping
What is a setback for dram theories
theories are difficult to directly test and variables are difficult to manipulate
