Localisation of function

Question 1

What is localisation of function?

Answer 1

Different areas of the brain are responsible for specific behaviours, processes or activities (cortical specialisation)

Question 2

What did Broca and Wernicke discover?

Answer 2

Specific areas of the brain

Question 3

What did scientists believe about brain function?

Answer 3

Holistic theory- all parts of the brain are involved in the processing of thought and action

Question 4

What is the cerebrum?

Answer 4

The main part of the brain

Question 5

What is the cerebrum divided into?

Answer 5

• 2 symmetrical halves:
• Right and Left hemispheres

Question 6

What controls activity on the left hand side of the body?

Answer 6

The right hemisphere

Question 7

What controls activity on the right hand side of the body?

Answer 7

The left hemisphere

Question 8

What is the cerebal cortex?

Answer 8

The outer layer of the brain’s hemispheres (3mm thick)

Question 9

What is the cortex divided into?

Answer 9

4 centres/’lobes’ of the brain:
- The frontal lobe
- The occipital lobe
- The parietal lobe
- The temporal lobe

Question 10

What is a lobe?

Answer 10

An organ that is separate from the others

Question 11

Where is the motor area located?

Answer 11

The back of the frontal lobe

Question 12

What is the function of the motor area?

Answer 12

Controls voluntary movement in the opposite side of the body
(Damage to motor lobe= loss of control over fine movements)

Question 13

Where is the somatosensory area located?

Answer 13

The front of both of the parietal lobes

Question 14

What is the function of the somatosensory area?

Answer 14

Sensory information from the skin is represented here

Question 15

Where is the visual area located?

Answer 15

The occipital lobe

Question 16

What is the function of the visual area?

Answer 16

Receives and processes visual information
(Each eye sends info from right visual field to left visual cortex)

Question 17

Where is the auditory area located?

Answer 17

The temporal lobe

Question 18

What is the function of the auditory area?

Answer 18

Analyses speech-based information
(Damage can produce partial hearing loss)

Question 19

What are the 2 language centres of the brain?

Answer 19

• Broca’s area
• Wernicke’s area

Question 20

What side of the brain is language limited to?

Answer 20

The left hand side

Question 21

What is Broca’s area?

Answer 21

• Located in the left frontal lobe
• Responsible for speech production
• Damage can cause Broca’s aphasia (slow, laborious speech, lacks fluency)

Question 22

What is Wernicke’s area?

Answer 22

• Located in the left temporal lobe
• Responsible for language understanding
• Damage can cause Wernicke’s apashia (produce nonsense words)

Question 23

What are the strengths of localisation?

Answer 23

• Evidence from neurosurgery
• Evidence from brain scans
• Case study evidence

Question 24

What are the limitations of localisation?

Answer 24

• Counter-evidence for localisation
• Language localisation questioned

Question 25

Strength:
I- Evidence from neurosurgery

Answer 25

D- Neurosurgery treats some mental disorders, which target specific areas of the brain (e.g: cingulotomy- isolating cingulate gyrus Dougherty et al- report on 44 people with OCD who had undergone a cingulotomy 32 weeks later- 30%= successful, 14%= partial response
E- Success suggests behaviour associated with mental disorders may be localised

Question 26

Strength:
I- Evidence from brain scans

Answer 26

D- Peterson et al used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task. LTM review by Buckner and Peterson- semantic and episodic memory resides in different parts of prefrontal cortex
E- Objective methods for measuring brain activity have provided accurate scientific evidence that functions are localised

Question 27

Limitation:
I- Counter-evidence for localisation

Answer 27

D- Lashey removed areas of the cortex (10-50%) in rats who learnt the route through a maze. No area was more important than any other. Learning process required every part of the cortex
E- Suggests higher cognitive processes (learning) are not localised but distributed in a more holistic way

Question 28

Limitation:
I- Language localisation questioned

Answer 28

D- Dick and Tremblay found 2% of modern researchers believe language is controlled fully by Broca and Wernicke’s areas. Scanning technique advances mean neural processes can be studied with more clarity (fMRIs). Language function= holistically distributed in brain. Language streams= across the cortex (thalamus, right hemisphere)
E- Suggests language is organised holistically, contradiciting localisation

Question 29

Evaluation extra:
I- Case studies

Answer 29

Strength: Phineas Gage- metal pole passed through his eye, into his skull- removed a portion of his left frontal lobe (responsible for planning, reasoning, control). His personality changed- he became rude and hostile. Supports localisation theory

Limitation: Hard to make meaningful generalisations from studies of one individual. Conclusions may depend on subjective interpretation of researchers. Case study evidence is low in validity