Chapter 14: Consciousness Flashcards
What are the 3 problems of consciousness?
- Problems of other minds: you don’t know what someone else experiences
- Qualia: first-person view, subjective experience
- Explanatory gap: how do you link subjective experience with workings of the brain?
What are philosophical zombies and what would that say over the dualism/materialism debate?
Physical beings like anyone else, except they lack consciousness
- If this is true, dualism would be true
What is the difference between dualism and materialism?
Dualism: physical body and non-physical mind. Therefore the mind can’t be studied scientifically
Materialism: everything is physical and can be studied scientifically
What is cortical blindness and what happens with blindsight?
Cortical blindness = destruction V1
Blindsight: blind man can’t see, but can avoid obstacles: unconscious zombie system
What is the contrastive approach to consciousness?
Conscious processing - unconscious processing = consciousness markers
Both for states and contents
What is the difference between states and contents of consciousness?
State: ability to experience consciousness as a state
- More subcortical (brainstem/thalamus)
Contents: reportable experience (I saw a red rose)
- More linked to cortex
What is the relationship between arousal and awareness?
Both describe states of consciousness and are enabling conditions
- Arousal: vigilance/wakefulness
- Awareness: level of consciousness
What does cerebellar agenesis show for symptoms and how does it relate to consciousness?
Little effect on consciousness, but does show motor deficits
What is akinetic mutism? What does this damaged area contribute to consciousness?
Damage to basal ganglia, which results in impairment of decision making, emotions and self-initiated actions
Basal ganglia damage leads to cognitive problems, but not full loss of consciousness
What is a vegetative state and how is it caused? What are the ethical difficulties?
Presence of arousal, but absence of consciousness
Caused by damage in brainstem and/or cortex
Patient can be misdiagnosed, because some patients can experience the world and have some consciousness, but aren’t able to report it. This is seen in brainscans
What is the consequence of lesions to the brainstem?
Coma or death
What is ARAS and what is its function for consciousness?
Ascending reticular activating system in brainstem, which includes basal forebrain and reticular nucleus of thalamus
It projects to the ILN (intralaminar nuclei) in the thalamus
What is the role of the brainstem in consciousness?
It provides background conditions (states) by depolarizing thalamic and cortical neurons
It’s insufficient for contents of consciousness
What is the role of the thalamus in consciousness?
Intralaminar nuclei (ILN) receive input from ARAS in brainstem that engage in cortico-thalamo-cortico loops. They control consciousness states and contents
What is the difference between thalamo-cortical loops and cortico-cortical loops?
Thalamo-cortical: control states
Cortico-cortical: control contents
What is the consequence of lesions to the ILN?
Coma or death
By stimulating what region can consciousness be restored?
Stimulation of ILN. This restores thalamocortical connectivity, which activates cortical areas to restore cortical responses
How do the EEG waves look for wakeful states vs. non-wakeful states? Where does REM fit into this?
Wakeful: fast low amplitude (alfa/beta)
Not awake: slow high amplitude (delta)
REM waves look like wakeful waves
What is the relationship between consciousness and the pattern of EEG waves?
Loss of consciousness results in slow high amplitude waves
How can neural correlates of contents of consciousness be studied?
- Binocular rivalry
- Masking
- Bistable stimuli
What is the contrastive approach?
Compare neural activity in conscious contents for unconscious contents
What is binocular rivalry? What can be concluded from research with this?
Both eyes are presented with dissimilar images that can’t be fused by the brain. Perception alternates between the two images
Object-selective visual cortex reflects conscious perception rather than the physical world
What is the difference between higher and lower level visual areas in consciousness?
V1: reflects stimulus better
V2-5: reflects percept better
Debatable what the role of V1 is in consciousness, maybe indirect
What are masking studies and what is the main conclusion?
Presenting a pattern that is masked and briefly shown.
Masked words activate high-level visual areas, but visible words activate them more
So consciousness of contents is reflected by higher activity in higher level sensory areas and frontoparietal activity
What is the global neuronal workspace theory?
Input:
- perception (present)
- long term memory (past)
- attention (focus)
- evaluative systems (value)
Output:
- Motor systems (future)
Is the PFC required for consciousness?
PFC reflects later cognitive processes (report + attention) rather than consciousness
- Alternations binocular rivalry is related to PFC, but only with explicit report
What is the difference between feedforward processing and recurrent processing/frontoparietal ignition?
Feedforward: unconscious
- Signals mainly go to frontal lobe
Recurrent processing/frontop. ignition:
- Exchange of signals all over the brain
