Localisation of function

Question 1

Robert suffered a stroke at the age of 55. After the stroke he was paralysed down his right side, though he could move his left arm and leg easily. Robert could clearly understand what was said to him, but was unable to produce any speech.

Discuss how knowledge of hemispheric lateralisation and language centres in the brain has helped our understanding of cases such as Robert’s.
Refer to Robert’s case in your answer

Answer 1

• different parts of the brain perform different functions

- functions are specific to individual parts of the parts

Question 2

what two halves is the brain divided into

Answer 2

the left and right hemisphere which are divided by a small gap

Question 3

what is localised to the left hemisphere

Answer 3

language

Question 4

what is localised to the right hemisphere

Answer 4

spatial skills

Question 5

what is hemispheric lateralisation

Answer 5

different sides of the brain perform different functions

Question 6

Patient tan lost the ability to speak. Based on your knowledge of hemispheric lateralisation, where did Tan have damage

Answer 6

left hemisphere

Question 7

what is Contralateral organisation

Answer 7

is when the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.

Question 8

what are both hemispheres of the brain involved in

Answer 8

the 5 senses and controlling our movement

Question 9

how do the right and left hemisphere communicate

Answer 9

communicate by sending nerve impulses to each other using the corpus callosum.

Question 10

what is the The corpus callosum

Answer 10

a bundle of axons that connect the hemispheres. It acts as a bridge between the two hemispheres

Question 11

Explain what is meant by contralateral brain organisation

Answer 11

Contra means ‘opposite’, and lateral means ‘side’, so contralateral means that some functions of the brain controls the opposite side of the body. Contralateral brain organisation means that the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.

Question 12

what does it mean if some functions are processes by only one side of the brain

Answer 12

they are hemispherically lateralised

Question 13

what is the cortex

Answer 13

the outer surface of the brain

Question 14

what does the motor cortex do

Answer 14

controls body movement on the right side of the body

Question 15

what does the somatosensory cortex do

Answer 15

processes the feeling of touch. the somatosensory cortex in the right hemisphere controls the left side of the body. and the somatosensory cortex in the left hemisphere controls the right side of the body

Question 16

where is the somatosensory cortex located

Answer 16

behind the motor cortex

Question 17

how does the auditory cortex process sounds

Answer 17

by receiving nerve impulses or impulses from sensory neurones that talk to sensory receptors in the ears

Question 18

where is the auditory cortex located

Answer 18

behind and slightly below the somatosensory cortex

Question 19

what does the auditory cortex do

Answer 19

processes sound. There is an auditory cortex in both hemispheres, but the auditory cortex is not organised contralaterally

Question 20

where is the visual cortex located

Answer 20

right at the back of the brain

Question 21

what des the visual cortex do

Answer 21

processes vison. Both hemispheres are involved in processing vison. The visual cortex works by receiving nerve impulses from sensory neurones that talk to sensory receptors in your eyes. Vison is organised contralaterally

Question 22

where is the brocas area located

Answer 22

below and slightly in front the motor cortex

Question 23

what is the function of brocas area

Answer 23

involved in producing language, so we can say it is hemispherical lateralised to the left hemisphere

Question 24

where is the Wernickes area located

Answer 24

behind the auditory cortex

Question 25

what is the function of wernickes area

Answer 25

• enables us to understand written language
• enables us to understand speech
• hemispherically lateralised to the left hemisphere

Question 26

what is aphasia

Answer 26

• when people lose the ability to produce language

- when people lose the ability to understand language

Question 27

what is brocas aphasia

Answer 27

inability to produce language

Question 28

what is Wernickes aphasia

Answer 28

inability to understand language

Question 29

Bella was in a terrible car crash and received severe damage throughout the whole cortex of her right hemisphere.
What symptoms would we expect Bella to exhibit?

Answer 29

• Loss of vision to the left of her body.
• Loss of movement to the left half of her body
• Loss of sensation of touch to the left half of her body.

Question 30

In a conversation, Joseph listens and can understand what people are saying. However, he struggles to express himself verbally. His dad suggested that he writes down what he thinks, or acts it out, but he struggles with this too - his left hand and arm feel like they’re not doing what he wants them to do.
Using the information above, explain what areas of Joseph’s brain might be damaged and why.

Answer 30

Joseph’s Broca’s area could be damaged because he is struggling to create language - he can’t find the right words to express himself. His right motor cortex may also be damaged, because he is struggling to use his left arm and hand, and his right motor cortex controls the left side of his body. Joseph isn’t having any problems with touch sensations, right side of his body or understanding language, so his somatosensory cortex, left motor cortex and Wernicke’s areas seem to be ok.

Question 31

what are the limitations of localisation of function

Answer 31

• may be over simplified because a complex function often requires more than one brain region/ area
• ignores the importance of communication between brain regions
• it ignores individual differences in brain organisation

Question 32

what are the criticism of patients tan research

Answer 32

Dronkers found that patient tan had damaged other regions of his brain outside of Brocas area. Dronkers supports the idea that more than one region is responsible for language production

Question 33

Explain why case studies of patients like Tan support the idea of brain localisation.

Answer 33

Tan displayed difficulties with producing language, and after he had died a post-mortem examination showed damage to his Broca’s area. This suggests that damage to that particular area had caused Tan’s symptoms, supporting that different areas have specific functions.

Question 34

Explain what Dejerne’s study tells us about brain localisation.

Answer 34

The study demonstrates that the idea that only one brain region contributes to a function is over-simplified. It also shows that even the idea of multiple brain regions contributing to a function is over-simplified. The study illustrates the importance of communication between brain regions, rather than just looking at one area as important to a function.

Question 35

what does localisation of function mean

Answer 35

Localisation of function is the theory that different areas of the brain are responsible for different behaviors, processes or activities.