the self and the brain

Question 1

theories of the mind

Answer 1

•Freud (19th century)
The mind is divided into irreconcilable parts. Much of its content and process is inaccessible to awareness.

•Experimental study of cognition (20th century)
Much of our learning and memory is implicit. We have poor awareness of mental processes. Our awareness of mental activity develops well after its actual onset.

Scientific work in the 20th century has destroyed ideas about the unity and accessibility of the mind. The view that has emerged is of the mind as a collection of interacting sub-systems, some relatively autonomous, some more associative, all working in parallel.

Question 2

franz galls phrenology

Answer 2

Gall believed in functionally specialized brain areas corresponding to elements of personality or character. He also (erroneously) believed that their size, as indicated by the corresponding protrusion on the skull, indicated the relative prominence of that character or trait in the individual

Question 3

occipital lobe

Answer 3

participates in vision processing. It processes and interprets everything we see.

Question 4

parietal lobe

Answer 4

vision, touch, attention, action

Question 5

frontal lobe

Answer 5

action, working memory, emotion, executive function

Question 6

temporal lobe

Answer 6

hearing, language, memory, vision

Question 7

cell membrane

Answer 7

the semi permeable membrane that encloses the neuron

Question 8

dendrites

Answer 8

the short processes emanating from the cell body, which receive most of the synaptic contacts from other neurons

Question 9

axon hillock

Answer 9

the cone shaped region at the junction between the axon and cell body

Question 10

axon

Answer 10

the long, narrow process that projects from the cell body

Question 11

cell body

Answer 11

the metabolic center of the neuron; also called the soma
The cell body pools the information arriving via dendrites and produces activation that travels down the axon to affect other cells.

Question 12

myelin

Answer 12

the fatty insulin around many axons

Question 13

nodes of ranvier

Answer 13

the gaps between sections of the myelin

Question 14

buttons

Answer 14

the button like endings of the axon branches, which release chemicals into the synapses

Question 15

synapses

Answer 15

the gaps between adjacent neurons across which chemical signals are transmitted

Question 16

cingulate gyrus

Answer 16

which we will encounter when when studying emotion.

Question 17

corpus callosum

Answer 17

a bundle of some 200 million axons that connects the left and right hemispheres of the brain.

The corpus callosum is essential to the coordinated operation of the mind as we know it because the two hemispheres have significant divisions of labour between them.

Question 18

The corpus callosum carries two types of connections between neurons in the brain:

Answer 18

• Homotopic connections

- heterotopic connections

Question 19

homotopic connections

Answer 19

are between spatially analogous locations across the hemispheres

Question 20

heterotopic connections

Answer 20

connect cells from one area of one hemisphere to another area of the other hemisphere.

Question 21

ipsilateral connections

Answer 21

between neurons that link areas within the same hemisphere.

Question 22

What do these callosal connections do?

Answer 22

In some cases, they allow the functional areas in the two hemispheres to cooperate. This happens in vision, for example, where some cortical neurons have receptive fields that span both visual hemifields connections

Question 23

callosotomy

Answer 23

Callosotomy has a good record of helping patients leave behind their debilitating condition and return to some semblance of normality. The aftermath of the procedure also presents an excellent opportunity to experimentally study what a mind divided along the hemispheres is like.

Question 24

why is a wada test used

Answer 24

• The corpus callosum is essential to the coordinated operation of the mind as we know it
because the two hemispheres have significant divisions of labour between them.
• it is beneficial to know as much as possible about the patient’s hemispheric specialisation of critical psychological functioning to avoid chance of tissue damage during operation

Question 25

what does a wada test involve

Answer 25

• one hemisphere of the brain is temporarily anesthetised by introducing sodium amytal into the left or right carotid artery.
• an angiogram is done to ensure that there are no blockages in blood flow. Then, sodium amytal is applied and the hemisphere is put to sleep.
• The doctor then tries to establish which aspects of speech, language and control are intact in the absence of the anesthetised hemisphere.
• They can also show a set of cards of pictures and words to recognise and remember. After the anesthetic wears off, the doctor can test for the patient’s level of recall and recognition memory. This gives surgeons a picture of the patient’s level of hemispheric specialisation of language and memory function.

Question 26

Hemifield presentation

Answer 26

Exploits the structure of the optic radiation from the eye to the visual centres in the occipital lobe. Assuming that the person fixates their eyes straight ahead, things that are presented to the left half of the visual field are processed by the right hemisphere, and things presented to the right half of the visual field are processed by the left hemisphere. The duration of presentation has to be too short for the person to make eye movements and, as it were, take in both visual hemifields into both hemispheres.

Question 27

Hemifield presentation study results

Answer 27

• LEFT hemisphere produces a verbal report, the RIGHT hemisphere doesn’t
• RIGHT hemisphere has perceived and processed the stimulus:
• It can direct the left hand to draw or pick up the stimulus object

^^What is presented to the left hemisphere (i.e., to the right visual hemifield) can be verbally reported. What is presented to the right hemisphere (i.e., to the left visual hemifield) cannot be verbally reported. However, the right hemisphere can show that it has seen and recognised the object if it is allowed to draw or pick up the object with the left hand (which is controlled from the right hemisphere).

Question 28

block design test

Answer 28

The patient’s task is to simply copy the spatial pattern shown on the card with the blocks that are provided. When attempting to do this with the left hand (controlled by the right hemisphere), there is no problem. Solution is swift and accurate. When trying with the right hand (controlled by the left hemisphere), this task proves impossible. This shows the right hemisphere to be specialised for the spatial information-processing capabilities required for this task.

• The apparently integrated sense of self emerges from interacting brain systems
• Many brain processes are out of conscious awareness
• There are multiple ‘agencies’ competing for control of action and awareness
• Intuition is usually a poor guide to how the mind works
• The conscious experience of selfhood is the result of a story-telling exercise
• This is most likely hosted in the left hemisphere