Localisation of function in the brain

Question 1

What is localisation of function?

Answer 1

The idea that certain locations or areas within the brain are responsible for certain behaviours, processes or actions (eg. Language, memory, perception)

Question 2

What are the 5 sections of the brain called?

Answer 2

1. Frontal lobe
2. Parietal lobe
3. Temporal lobe
4. Occipital lobe
5. Cerebellum

Question 3

The main part of the brain (the cerebrum) is divided into two halves - what do we call them?

Answer 3

Left and right hemisphere

Question 4

What is the general rule regarding the 2 hemispheres?

Answer 4

Activity on the left side of the body is controlled by the right hemisphere

Activity on the right side of the body is controlled by the left hemisphere

Question 5

What is the outer layer of both hemispheres called?

Answer 5

The cerebral cortex - about 3mm thick and made of ‘grey matter’ containing neurons (brain cells)

Question 6

Where is the motor area located?

Answer 6

The motor centres are at the back of the frontal lobe

Question 7

What is the function of the motor area?

Answer 7

They control voluntary movement in the opposite side of the body - damage may cause loss of control of fine movements

Question 8

Motor area: Left, right or both hemispheres?

Answer 8

Both

Question 9

Where is the somato-sensory area?

Answer 9

In the front of both parietal lobes

Question 10

What is the function of the somato-sensory area?

Answer 10

Separated from the motor area by a ‘valley’ called the central sulcus
Sensory info relating to sensations of touch, pressure, pain and temperature are processed from the skin
Info is recieved from the opposite side of the body - the amount of somatosensory area devoted to a particular body part denotes its sensitivity

Question 11

Somato-sensory area: Left, right or both hemispheres?

Answer 11

Both

Question 12

Where is the visual area located?

Answer 12

Occipital lobe at the back of the brain

Question 13

What is the function of the visual area?

Answer 13

Info from the eyes is carried to the visual cortex via the optic nerve which passes through the centre of the brain

Question 14

Visual area: Left, right or both hemispheres?

Answer 14

Both
(Info from the right visual field travels to the left visual cortex - info from the left visual field travels to the right visual cortex)

Question 15

Where is the auditory area located?

Answer 15

Found in the temporal lobes

Question 16

What is the auditory area’s function?

Answer 16

Auditory nerves transmit signals from the cochlea - these process speech-based info
Damage may produce partial hearing loss (the more extensive the damage the greater the loss)

Question 17

Auditory area: Left, right or both hemispheres?

Answer 17

Both

Question 18

Where is Broca’s area located?

Answer 18

Small area of the frontal lobe

Question 19

What is the function of Broca’s area?

Answer 19

Responsible for speech production

Question 20

Broca’s area: Left, right or both hemispheres?

Answer 20

Left

Question 21

Where is Wernicke’s area located?

Answer 21

Left temporal lobe

Question 22

What is the function of Wernicke’s area?

Answer 22

Responsible for language comprehension

Question 23

Wernicke’s area: Left, right or both hemispheres?

Answer 23

Left

Question 24

Why does Broca’s area control speech production?

Answer 24

Broca’s area is close to brain regions that control the mouth, tongue and vocal cords

Question 25

Why does Wernicke's area control language comprehension?

Answer 25

Wernicke's area is close to brain regions responsible for auditory and visual input

Question 26

Give 3 strengths of localisation of function in the brain

Answer 26

1. Brain scan evidence - Petersen et al (1998) used brain scans to show acitivity in Wernicke's area during a listening task and in Broca's area during a reading task - suggesting these areas of the brain have different functions A study of LTM by Tulving et al (1994) revealed that semantic and episodic memories are located in different parts of the frontal cortex There are now sophisticated and objective methods of measuring brain activity which provides scientific evidence of localisation of function 2. Neurological evidence - Neurosurgery is a last resort method for treating some mental disorders Freeman (1950s) surgically removed or destroyed areas of the brain to control behaviour - although brutal and imprecise Dougherty et al (2002) reported 44 OCD patients who had cingulotomy. At a 32 week follow up, 1/3 showed improvement and 14% partially responded to treatment The success of these procedures strongly suggest that symptoms and behaviours associated with serious mental disorders are localised 3. Case studies - Phineas Gage During an explosion, while working on the railroad, a meter-long pole went through his skull The damage to his brain changed his personality - he went from being calm to quick-tempered and rude The change in Gage's temperament following the accident suggests that the frontal lobe is responsible for regulating mood

Question 27

Give a limitation of localisation of function in the brain

Answer 27

Contradictory research - Lashley (1950) suggests higher cognitive functions are not localised but distributed in a more holistic way in the brain Lashley removed between 10% and 50% of the cortex of rats learning a maze - the amount of brain removed didn't alter the rats ability to complete the maze The learning required every part of the cortex which suggested learning is too complex and involves the whole brain