Class 22 Flashcards
Two dimensions of consciousness
- Wakefulness
- Awareness
Qualia
subjective aspects of experience
The explanatory gap
(or the hard problem)
can one get from physicalism to explaining qualia?
Realism asserts that consciousness
is a distinct property
illusionism argues that consciousness
doesn’t actually exist and the question is why we think it does
Reticular activating system mainly comprised of input from (is involved in)
(RAS)
brainstem (medulla and pons)
• Arousal, sleep-wake cycles
Damage to different areas the reticular activating system this system can result in
varying degrees of disorders of consciousness
2 pathways of the RAS
Dorsal (acetylcholine)
Ventral (norepinephrine + serotonin)
Dorsal RAS Pathway
(acetylcholine): thalamus, modulates cortical excitation
Ventral RAS Pathway
(norepinephrine + serotonin): hypothalamus + basal forebrain, sleep and wakefulness
Sleep/wake cycles coordinated via the
suprachiasmatic nucleus (SCN) of the hypothalamus
Both __ and __ mechanisms are implicated in controlling arousal
circadian and homeostatic mechanisms (e.g. adenosine)
Sleep pressure
adnosine involved in
Homeostatic systems for ___ work by ____
sleep promotion work by
inhibiting the RAS and other parts of the arousal circuitry
Caffeine is an ____
adenosine receptor antagonist and prevents adenosine’s effects
P3a respond to __
Amplitude of P3a has been considered ___
rare, task-irrelevant sounds
an index of how ‘distracted’ someone is by an incoming sound that is not relevant to the task at hand
P3b respond to __
P3b is taken as an ___
task-relevant target processing
indication that the participant is processing this information actively and has awareness of it
P3b
P3b is taken as an ___
task-relevant target processing
indication that the participant is processing this information actively and has awareness of it
Patterns of activity that accompany a specific experience can be studied by ___
looking at stimuli that do not differ in physical quality but can report different percepts (i.e. multistable illusions)
Differential perception of an illusion also changes
underlying neural patterns for the same stimulus, according to variations in what and where is heard
Awareness without attention:
dual-task studies where unattended info was identified
Attention without awareness:
masked priming studies
We can only be conscious about a limited ___ but __-
number of things at a time, but
even information that doesn’t reach our consciousness is processed
(ex. masked priming)
Disorders of consciousness clinically defined as
when there is a failure to either the systems responsible for wakefulness/aroussal or awareness
Unresponsive wakefulness state demonstrates
persistent vegetative state
sleep/wake cycles, spontaneous breathing, reflexes, but does no show capacity to interact with others
Minimally conscious state, demonstrates
Can demonstrate some measurable evidence of awareness, such as responding to yes/no questions
Behavioural assessments of consciousness can
be unreliable and lead to a misdiagnosis of a patient
Libet’s task
Unscheduled activity with a weak imperative to move:
‘You can do it whenever you want… but you should do it at some point’
Look at clock as hand move around screen - at some point move hand. Tried to mesure when person choese to move hand. Take note when you had concous desire to move happened. Mesure EEG activity. slow ramp up to when someone makes activty begining 3 seconds before move but concouss report its millasceonds before move. - Free Will?
Problems with Libet
only timeframs when making dicisson but not when deciding to not do something
by removing all times movement didnt have, removing some random flucutations.
Researchers have been able to decode what a subsequent choice of digit would be based on
neural activity from up to 4 seconds prior
If red line is the peak of activity where decisson is made, but activity increased even before conous awatness, decpde what discission is made.
In the absence of a purpose for action, it may be that ____ contribute an impetus for when to move
flucations of neural activity
deliberate movements & readiness potential
Unlike arbitrary movements, deliberate movements did not demonstrate a readiness potential
Deleberatte vs arbartary result - (arbtary the dicisson made has no impact on the result)
delebrate - give money to one org vs another - no ramp of activity charatraize readness potental. - actuall decission making
What is Concsciousness
awarnes of ones onwn existance, sensation, thoughts, surroundsings, etc.
having an experence
masked priming
presented very quickly
not report what they saw
but still see that informatoin has an input
locked in syndrome
arrousal and awarness but cannot move body at all
(but could blink)
Communicating with people with DOCs
in MRI ask to imagine tenis or imagne walking in room
expect areas involved in spatal processing to be actvated
Stduy shows can hear and respons accodignly to directoins, give oppurtunity to ask other questions
