BP- Localisation of Function

Question 1

What does localisation of function mean?

Answer 1

Localisation of function refers to the principle that functions (language,memory,hearing etc.) have specific locations within the brain.

Question 2

What are the four types of cortex?

Answer 2

Visual, auditory, somatosensory and motor cortex

Question 3

Where is the visual cortex found?

Answer 3

• The visual cortex is the occipital lobe of BOTH hemispheres of the brain.

Question 4

What happens during visual processing?

Answer 4

• Visual processing starts in the retina where light enters and strikes the photoreceptors.
• Nerve impulses from the retina are transmitted to the brain via the optic nerve.
• The majority terminate in the thalamus, which acts as a relay station, passing the information onto the visual cortex.

Question 5

Where is the auditory cortex found?

Answer 5

The auditory cortex lies within the temporal lobe in BOTH hemispheres of the brain.

Question 6

What happens in the auditory pathway?

Answer 6

• The auditory pathway begins in the cochlea in the inner ear,where sound waves are converted to nerve impulses, which travel via the auditory nerveto the auditory cortex.
• Basic decoding occurs in the brainstem, the thalamus carries out further processing before impulses reach the auditory cortex.

Question 7

Where is the motor cortex found?

Answer 7

The motor cortex is located in the frontal lobe of BOTH brain hemispheres.

Question 8

What is the motor cortex is responsible for?

Answer 8

The motor cortex is responsible for the generation of voluntary motor movements.

Question 9

Where is the somatosensory cortex found?

Answer 9

It is located in the parietal lobe of BOTH hemispheres.

Question 10

What is the role of the somatosensory cortex?

Answer 10

• This area detects sensory events arising from different regions of the body.
• Using sensory information from the skin, the somatosensory cortex produces sensations of touch, pressure, pain and temperature.

Question 11

Where are the language centres found?

Answer 11

ONLY the left hemisphere

Question 12

Where is the Broca’s area located?

Answer 12

In the frontal lobe of the left hemisphere

Question 13

What is expressive aphasia?

Answer 13

• Expressive aphasia is language/speech problems caused by damage to the Broca’s area.
• It affects language production but not understanding.
• The speech lacks FLUENCY.

Question 14

What is receptive aphasia?

Answer 14

• Receptive aphasia is an impaired ability to UNDERSTAND language as a result of damage to the Wernicke’s area.

Question 15

Where is the Wernicke’s area located?

Answer 15

It is located in LEFT hemisphere in the temporal lobe.

Question 16

Evaluation of Localisation of function.

Answer 16

(+)

1) Language centres are supported by aphasia studies.
2) Further supporting evidence comes from brain scans e.g petersen et al
3) Phineas Gage was in an accident which caused him to lose part of his frontal lobe which altered his personality - The frontal lobe may play a role in mood regulation therefore localisation theory is correct. (CP: CASE STUDIES LACK GENERALISABILITY.)

(-)

1) Communication may be more important than localisation e.g Dejerine
2) Individual differences in language areas e.g Baveiler
3) Lashley removed areas of the cortex in rats that were learning a maze and found no area of brain was proven to be more important, meaning every part of context is needed to learn the maze, suggests that higher cognitive functions like problem solving are distributed holistically not localised in brain (law of equipotentiality). and PLASTICITY of the brain lends support to the HOLISTIC theory because people who damage part of the brain through, for example, having a STROKE, are able to RECOVER function that has been lost. The brain is working as a WHOLE UNIT rather than specific areas for specific functions.

Question 17

What did Bavelier et al find in 1997?

Answer 17

Bavelier et al. (1997) found that there are individual differences in which brain areas are activated when a person is engaged in silent reading. They observed activity in the right temporal lobe, left frontal lobe and occipital lobe.

Question 18

What did Dejerine deduce in 1892?

Answer 18

It may be that how brain areas communicate with each other is more important than specific brain regions. Dejerine (1892) reported a patient who could not read because of damage between the visual cortex and Wernicke’s area.

Question 19

How did Petersen et al use brain scans to support localisation of function?

Answer 19

He used brain scans to demonstrate that the Wernicke’s area was active during listening tasks and the Broca’s area was active during reading tasks.