localisation of the brain: evaluation

Question 1

there are brain scan evidence for the localisation of the brain

Answer 1

there is a wealth of evidence producing support for the idea that many neurological functions are localised - particularly in relation to language and memory

e.g. Perterson et al (19888) used brain scans to demonstrate how Wernicke’s area was active during listening task and Broca’s area was active during a reading task, suggesting that these areas if the brain have different functions

Question 2

what is another study that provides evidence for localistaion

Answer 2

a study of long term memory by Tulving et al (1994)) revealed that semsntic and episodic memories reside in different parts of prefrontal cortex

There now exists a number of highly sophisticated and objective methods for measuring activity in the rain which provide sound scientific evidence of localisation of brain function

Question 3

what is the neurological evidence for localisation

Answer 3

the practice of surgically removig or destroying areas of the brain to control aspects of behaviour developed in 1950s

early attempts were pioneered by Walter Freeman who developed lobotamy - were brutal imprecise and typically involved severing connections in the frontal lobe in an attempt to control aggressive behaviour

It is still used today although sparingly
in extreme cases of OCD and depression

e.g. Dougherty et al (2002) reported on 44 OCD patients who had undergone a cinglutomy

Question 4

what is a cinglutomy

Answer 4

it is a neurosurgical procedure that involves lesioning off the cingulate gyrus

Question 5

what does the post surgical follow up of the cinglutomy prove

Answer 5

at post - surgical follow up after 32 weeks a third had met the criteria for successful response to the surgery and 14% for partial response

the sucess of procedures like this strongly suggests that symptoms and behviour behviour associated with mental disorders are localised

Question 6

how does the plasicity of the brain discredits the theory of localisation

Answer 6

when the brain becomes damages
e.g. illness or accident
and a particular function has been comprised or lost, the rest of the brain appears to be able too reorganise itselves in an attempt to recover the lost function

Lashey described this ass the LAW OF EQIPOTENTIALITY whereby surviving brain circuits “chip in” so the same neurological action can be achieved

although this does not happen every time, there are several documented cases of stroke victims being able to recover those abilities that were seemingly lost as a result of an a illness of accident

Question 7

what does the plasticity of the brain support instead of the localisation of the brain

Answer 7

plasticity of brain support holistic theory not localisation because people who take damage to the brain can recover the function that has been lost - essentially another part of the brain takes over

The brain is therefore a whole unit rather than specific areas for specific functions - which is what the localisation theory suggest

Question 8

language localisation is questioned

Answer 8

One limitation is that language may not be localised just to Broca’s and Wernicke’s area

A recent review by Antony Dick and Pascale Tremblay (2016) found that only 2% of modern researchers think that language in the brain is completely controlled by Broca’s and Wernicke’s areas
Advances in brain imaging techniques, such as fMRI, mean that neural processes in the brain can be studied with more clarity than ever before

It seems that language function is distributed far more holistically in the brain than was first thought
So-called language streams have been identified across the cortex, including brain regions in the right hemisphere as well s subcortical regions such as the thalamus

This suggests that, rather than being confined to a couple of key areas, language may be organised more holistically in the brain, which contradicts localisation