cerebral asymmetry and consciousness (L4) - Matt Roser

Question 1

What historical views are discussed in the lecture regarding consciousness?

Answer 1

Dualism and monism

Question 2

What is Cartesian Dualism?

Answer 2

The view that mind and body are separate realms

Question 3

What did Descartes contribute to psychology?

Answer 3

Formulated ideas on the nature of the mind and control of behavior

Question 4

According to Descartes, what is the essence of our being?

Answer 4

Mind is essential to our being in a way that body is not

Question 5

What did Aristotle believe regarding the soul?

Answer 5

The soul is the essence of being with no distinction between mind and body

Question 6

What was the pneumatic theory of the brain proposed by Galen?

Answer 6

Involved ventricles and animal spirits

Question 7

What did Descartes’ ‘De Homine’ outline?

Answer 7

The role of ‘animal spirits’ in reflex action

Question 8

What did Descartes imply about human behaviors?

Answer 8

Most human behaviors can be understood through the investigation of animal behavior

Question 9

What is the relationship between mind and body according to Descartes?

Answer 9

Mind and body are separate, with the body being a mechanical system

Question 10

What does the term ‘Cogito, ergo sum’ translate to?

Answer 10

‘I think, therefore I am’

Question 11

What is the ‘Cognitive Revolution’?

Answer 11

A movement in the 1960s rejecting dualism and adopting a monist/materialist stance

Question 12

Fill in the blank: Modern cognitive neuroscience suggests we may be just ______ that construct the illusion of a mind.

Answer 12

bodies

Question 13

What is consciousness?

Answer 13

The ability to report on one’s mental states and processes

processes and states like being awake, alertness, attention, reportable states and self-awareness

Question 14

What are the three tractable characteristics of consciousness?

Answer 14

• Operationalized
• Implementation
• Adaptivity

Question 15

What phenomenon is associated with blindsight?

Answer 15

Residual visual function and consciousness despite damage

Question 16

What is the significance of brain lesion patients in understanding consciousness?

Answer 16

They provide evidence against Descartes’ intuition about the enduring nature of the mind

Question 17

True or False: Descartes believed the mind and body were fundamentally the same.

Answer 17

False

Question 18

What does the global neuronal workspace model suggest about consciousness?

Answer 18

Consciousness is a global pattern of activity across the brain

Question 19

What is the main argument against Descartes’ view on the unity of the mind?

Answer 19

Evidence from brain lesions suggests the mind is not unitary

Question 20

What does the term ‘qualia’ refer to?

Answer 20

Subjective experience

Question 21

What is the main distinction between access consciousness and phenomenal consciousness?

Answer 21

Access consciousness is reportable; phenomenal consciousness is subjective experience

Question 22

What is cerebral asymmetry?

Answer 22

Anatomical and functional differences between the two hemispheres of the brain

It involves how cognitive processes are lateralized in the brain.

Question 23

What separates the two hemispheres of the brain?

Answer 23

The Longitudinal / Sagittal fissure

This fissure divides the left and right hemispheres anatomically.

Question 24

What connects the two hemispheres of the brain?

Answer 24

Commissures, including the Corpus Callosum and Anterior Commissure

The Corpus Callosum contains over 200 million axons, 95% of which are myelinated.

Question 25

What are homotopic, heterotopic and ipslateral connections?

Answer 25

Connections between corresponding areas of the two hemispheres

These connections are strictest between primary cortex areas.

Question 26

What is the role of the Planum Temporale?

Answer 26

Auditory processing supporting language

It shows anatomical asymmetries that are important for language comprehension.

Question 27

How can each hemisphere be tested?

Answer 27

Using lateralized visual presentation and dichotic listening

These methods reveal differences in processing between hemispheres.

Question 28

What is commissurotomy?

Answer 28

Section of the interhemispheric commissures

This procedure is often performed to prevent seizure spread.

Question 29

What is disconnection syndrome?

Answer 29

Condition where each cerebral hemisphere is disconnected from the other at the cortical level, preventing spread of seizure activity from one side to the other
-shown in sperry, 1982 split brain experiment

It results in unique behavioral characteristics in split-brain patients.

Question 30

What does the split-brain experiment reveal?

Answer 30

Hemispheric integration via commissures, and the independence of each hemisphere
-more specifically, subcortical commissures & limited transfers, partial callosotomy & specificty of transfer

Controlled experiments can demonstrate how each hemisphere functions separately.

Question 31

What is the significance of the right visual field (RVF) in split-brain patients?

Answer 31

Faster and more accurate naming by the left hemisphere

This indicates that language centers are predominantly left-hemispheric.

Question 32

What cognitive processes are superior in the right hemisphere?

Answer 32

Construction, detecting offsets, orientation, mirror reversal, and perceiving degraded stimuli
-extracts higher level percepts from the visual array

The right hemisphere is involved in higher-level perceptual tasks.

Question 33

What happens during unilateral brain damage?

Answer 33

Disruption of local or global representation depending on the side affected

Left brain damage disrupts local representation; right brain damage disrupts global representation.

Question 34

What is the left-hemisphere interpreter role?

Answer 34

The left hemisphere’s tendency to confabulate and look for patterns

This reflects the left hemisphere’s role in verbal and analytical tasks.

Question 35

What is the effect of task difficulty on hemispheric cooperation?

Answer 35

Increased task difficulty leads to a bilateral advantage

Performance improves when tasks require bilateral processing rather than unilateral.

Question 36

Fill in the blank: The _______ allows for fast intrahemispheric processing necessary for functions like language.

Answer 36

divided brain

Question 37

True or False: Hemispheric differences are absolute and do not change with task demands.

Answer 37

False

Hemispheric differences are relative and fluid, changing with stimulus and task requirements.

Question 38

what is the anatomy of the hemispheres?

Answer 38

seperated by longitudinal/sagittal fissures
-connected by commissures

Question 39

what is anatomical asymmetry?

Answer 39

anterior RH and LH overlap midline
-sylvian fissure: ascends more anteriorly in the right hemisphere, longer in left hem

Question 40

in which regions of the brain, does anatomical asymmetry occur?

Answer 40

-Planum Temporale
-Wernickes Area
-Auditory processing supporting language

Question 41

what is visual and auditory input predominantly?

Answer 41

contralateral

Question 42

why is FMRI useful in testing each hemisphere?

Answer 42

reveals lateralisation of the main brain regions involved in cognitive processes

Question 43

how is the split brain tested?

Answer 43

-each side of visual space projects to opposite side of the brain
-technique is to flash info quickly to one or othr side before eye movements can occur
-allows properties of each side of the brain to be assesed

Question 44

what is the specificty of transfer?

Answer 44

Anterior hemisphere - semantic transfer
Central hemisphere- Motor transfer
Posterior hemisphere - sensory transfer

Question 45

why do we have a divided brain?

Answer 45

more efficient use of cortical space
allows for fast processing, necessary for functions like language

Question 46

what is the modern cognitive neuroscience view?

Answer 46

we may just be bodies that construct the illusion of a mind

Question 47

what did Moutoussis & Zeki, 2002 find?

Answer 47

differences in brain processes for consciously perceived vs non percieved stimuli
-concluded from brain activitiions in respond to stimuli that are not consciously perceived
-colour reversed faces are displayed seperately to the two eyes -> binocular fusion occurs and subjects report seeing onlt the colour that results from the combination of the two stimulus colours

Question 48

what do models of consciousness show?

Answer 48

activations associated with percieved stimuli were many times more intense than those seen with unpercieved stimuli and were accompanied by activity at additional sites
-only reach consciousness if it is integrated into a large scale system of cortical activity
-attentional amplificatino leads to interaction of modular processes allowing information to be mainintaned and influence other processes

Question 49

what is suggested by lesion patients?

Answer 49

fractionated consciousness
-damage reduces function and it can also reduce awareness of that deficit