localisation of function in brain

Question 1

what is localisation of function?

Answer 1

Broca and Wernicke
different areas of brain responsible for specific behaviours, processes or activities

if certain area damaged- function associated also affected

Question 2

hemispheres of brain

Answer 2

cerebrum (main part of brain) divided into left and right hemisphere

lateralisation- some physical and psychological functions dominated by particular hemisphere

left hemisphere- controls activity on right-hand side of body
right hemisphere- controls activity on left-hand side of body

Question 3

what is the cerebral cortex (outer layer of hemispheres) subdivided into?

Answer 3

frontal lobe, parietal lobe, occipital lobe and temporal lobe

lobe- part of an organ that is separate in some way from the rest
each brain lobe associated with diff functions

Question 4

motor area

Answer 4

at back of frontal lobe (both hemispheres)

controls voluntary movement in opposite side of body

damage- loss of control over fine movements

Question 5

somatosensory area

Answer 5

at front of both parietal lobes, separated from motor area by central sulcus

processes sensory info from skin (e.g. touch, heat, pressure, etc.)

amount of area devoted to particular body part depends on sensitivity- e.g. receptors for face and hands occupy over half

Question 6

visual area (cortex)

Answer 6

part of occipital lobe

receives and processes visual info
each eye send info from right visual field to left visual cortex, left visual field to right visual cortex

damage to left hemisphere- blindness in part of right visual field of both eyes, and vice versa

Question 7

auditory area

Answer 7

part of temporal lobes

analyses speech-based info

damage- partial/complete hearing loss

Question 8

language centres of brain

Answer 8

language restricted to left side of brain in most people

Question 9

Broca’s area

Answer 9

area in left frontal lobe

responsible for speech production

damage- Broca’s aphasia (slow, laborious and influent speech)

e.g. ‘Tan’- patient of Broca’s who could only say ‘tan’

Question 10

Wernicke’s area

Answer 10

area in left temperable lobe

responsible for language comprehension

damage- Wernicke’s aphasia (nonsense words/neologisms as part of speech content)

Question 11

strength- evidence from neurosurgery

Answer 11

damage to areas of brain linked to mental disorders

cingulotomy- isolating cingulate gyrus region which has been implicated in OCD
Dougherty- 44 OCD patients underwent it, after 32 weeks 30% successful response, 14% partial

strength- behaviours associated with mental disorders localised, accurate

Question 12

strength- evidence from brain scans

Answer 12

many everyday brain functions localised

Peterson- brain scans showed Werncike’s area active in listening task and Broca’s area active in reading task

Buckner and Peterson- reviewed LTM studies, semantic and episodic memories located in diff parts of prefrontal cortex

strength- localised areas for everyday behaviours, objective methods for measuring brain activity, accurate

Question 13

however- Lashley brain study

Answer 13

removed areas of cortex (10-50%) in rats learning route through maze
no area proven more important than another in rats ability to learn route
seemed to require every part of cortex

criticism- higher cog processes like learning distributed holistically rather than localised, limited

Question 14

criticism- language localisation can be questioned

Answer 14

dick and Tremblay- only 2% of modern researchers believe language completely controlled by Broca’s and Wernicke’s areas
advances in brain imaging techniques (e.g. fMRI)- neural processes studied more thoroughly

language function distributed more holistically
language streams identified across cortex- including right hem brain regions and subcortical regions like thalamus

criticism- contradicts localisation theory, inaccurate