Localisation of function in the brain (incl broca’s and Wernicke’s areas)

what is localisation?

localisation suggests that the different functions of the brain are localised in specific areas and are responsible for different behaviours, processes or activities.

motor area

located in frontal lobe

regulation of movement

somatosensory area

area of the parietal lobe

processes sensory information e.g. touch

visual area

part of the occipital lobe

receives and processes visual informaion

auditory area

located in the temporal lobe

analysis of speech

name the 2 language centres

Broca’s area and Wernicke’s area

Broca’s area

area of the frontal lobe in left hemisphere

speech production

Wernicke’s area

area of temporal lobe (encircling the auditory cortex) in left hemisphere

language comprehension

how many hemispheres is the brain divided into?

2 symmetrical halves w

what is the cerebral cortex?

the outer layer of both hemispheres which covers all the inner parts of the brain. It is 3mm thick and appear grey due to the location of cell bodies

function of frontal lobe

contains motor area at the back in both hemispheres.

The motor area controls voluntary movement in the opposite side of the body

function of parietal lobe

at the front is the somatosensory area, which is where sensory information from the skin is presented

function of occipital lobe

contains the visual area, responsible for processing visual information

info from the eyes goes from right visual field to left visual cortex and from left visual field to right visual cortex

function of temporal lobe

contains the audiory area, which processes speech based information. Also contains Wernicke’s area which deals with speech comprehension

Broca’s aphasia

speech is slow and lacking in fluency- not all words are impacted equally e.g. nouns and verbs can be relatively unaffected but conjunctions can not be spoken

Paul Broca performed a post-mortem on a patient with severe speech production issues and found extensive damage to the left frontal lobe

Wernicke’s aphasia

inability to comprehend langauge and struggle to locate the words

Carl Wernicke found that patients who had damage in the area close to the auditory cortex in the left temporal lobe had these language impairements

holistic theory

brain works as a whole

AO3- neurological studies

P- neurological studies to support brain localisation

e- Peterson et al- Wernicke’s area active during listening task and Broca’s area active during reading aloud task- shows diff areas used for diff functions. brain scans- good methodology- reliable, repeatable, highly contrlled and scientific- no bias

e- Dougherty et al- lesioning the cingulate gyrus improved symptoms of OCD- as cutting an area reduced symptoms of OCD this suggests OCD is localised in this area (1/3 of patients significanty improved)Symptoms and behaviours of mental disorders are localised. Neurosurgery- good method, highly scientific

l- highly scientific evidence for localisation

A03- case study

p-evidence both for and against localisation from Clive Wearing

e-damage to hippocampus due to viral infection caused damage to his semantic long term memeory but not to his procedural memory

e-suggests localisation because if memory was spread throughout brain would not have this specific details. HOWEVER, still could remember a few facts(holistic?) also only 1 person and unique situation

AO3 evidence against localisation

P- evidence against localisation

e- Lashley- research on learning processes in rats. Lashley removed beween 10-50% of areas of the rats cortex. The rats were learning a maze No particular area was shown to be more important in the rats ability to complete the maze. Suggests higher cognitve functons are distributed in brain and require every part of the cortex- suggest more holistic. BUT rats not humans

e- neuroplasticity - when brain is damaged(and a particular function is damaged or compromised) the rest of brain reorganises itself to adapt- brain works as one (holistic)