Chapter 14: Consciousness

Question 1

What are the 3 problems of consciousness?

Answer 1

1. Problems of other minds: you don’t know what someone else experiences
2. Qualia: first-person view, subjective experience
3. Explanatory gap: how do you link subjective experience with workings of the brain?

Question 2

What are philosophical zombies and what would that say over the dualism/materialism debate?

Answer 2

Physical beings like anyone else, except they lack consciousness
- If this is true, dualism would be true

Question 3

What is the difference between dualism and materialism?

Answer 3

Dualism: physical body and non-physical mind. Therefore the mind can’t be studied scientifically

Materialism: everything is physical and can be studied scientifically

Question 4

What is cortical blindness and what happens with blindsight?

Answer 4

Cortical blindness = destruction V1

Blindsight: blind man can’t see, but can avoid obstacles: unconscious zombie system

Question 5

What is the contrastive approach to consciousness?

Answer 5

Conscious processing - unconscious processing = consciousness markers

Both for states and contents

Question 6

What is the difference between states and contents of consciousness?

Answer 6

State: ability to experience consciousness as a state
- More subcortical (brainstem/thalamus)

Contents: reportable experience (I saw a red rose)
- More linked to cortex

Question 7

What is the relationship between arousal and awareness?

Answer 7

Both describe states of consciousness and are enabling conditions
- Arousal: vigilance/wakefulness
- Awareness: level of consciousness

Question 8

What does cerebellar agenesis show for symptoms and how does it relate to consciousness?

Answer 8

Little effect on consciousness, but does show motor deficits

Question 9

What is akinetic mutism? What does this damaged area contribute to consciousness?

Answer 9

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

Question 10

What is a vegetative state and how is it caused? What are the ethical difficulties?

Answer 10

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

Question 11

What is the consequence of lesions to the brainstem?

Answer 11

Coma or death

Question 12

What is ARAS and what is its function for consciousness?

Answer 12

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

Question 13

What is the role of the brainstem in consciousness?

Answer 13

It provides background conditions (states) by depolarizing thalamic and cortical neurons
It’s insufficient for contents of consciousness

Question 14

What is the role of the thalamus in consciousness?

Answer 14

Intralaminar nuclei (ILN) receive input from ARAS in brainstem that engage in cortico-thalamo-cortico loops. They control consciousness states and contents

Question 15

What is the difference between thalamo-cortical loops and cortico-cortical loops?

Answer 15

Thalamo-cortical: control states
Cortico-cortical: control contents

Question 16

What is the consequence of lesions to the ILN?

Answer 16

Coma or death

Question 17

By stimulating what region can consciousness be restored?

Answer 17

Stimulation of ILN. This restores thalamocortical connectivity, which activates cortical areas to restore cortical responses

Question 18

How do the EEG waves look for wakeful states vs. non-wakeful states? Where does REM fit into this?

Answer 18

Wakeful: fast low amplitude (alfa/beta)
Not awake: slow high amplitude (delta)

REM waves look like wakeful waves

Question 19

What is the relationship between consciousness and the pattern of EEG waves?

Answer 19

Loss of consciousness results in slow high amplitude waves

Question 20

How can neural correlates of contents of consciousness be studied?

Answer 20

• Binocular rivalry
• Masking
• Bistable stimuli

Question 21

What is the contrastive approach?

Answer 21

Compare neural activity in conscious contents for unconscious contents

Question 22

What is binocular rivalry? What can be concluded from research with this?

Answer 22

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

Question 23

What is the difference between higher and lower level visual areas in consciousness?

Answer 23

V1: reflects stimulus better
V2-5: reflects percept better

Debatable what the role of V1 is in consciousness, maybe indirect

Question 24

What are masking studies and what is the main conclusion?

Answer 24

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

Question 25

What is the global neuronal workspace theory?

Answer 25

Input:
- perception (present)
- long term memory (past)
- attention (focus)
- evaluative systems (value)

Output:
- Motor systems (future)

Question 26

Is the PFC required for consciousness?

Answer 26

PFC reflects later cognitive processes (report + attention) rather than consciousness
- Alternations binocular rivalry is related to PFC, but only with explicit report

Question 27

What is the difference between feedforward processing and recurrent processing/frontoparietal ignition?

Answer 27

Feedforward: unconscious
- Signals mainly go to frontal lobe

Recurrent processing/frontop. ignition:
- Exchange of signals all over the brain