Localisation of function in the brain

Localisation of function

The theory that different areas of the brain are responsible for specific behaviours, processes or activities

Motor centre

A region of the frontal lobes of each hemisphere involved in regulating movement

Auditory centre

Located in the temporal lobes of each hemisphere.

Concerned with the analysis of speech-based information

Somatosensory centre

An area of the parietal lobes of each hemisphere that processes sensory information such as touch

Visual centre

A part of the occipital lobes of each hemisphere that receives and processes visual information

Broca’s area

An area of the frontal lobe in the left hemisphere

Responsible for speech production

Leads to Broca’s aphasia - limited amount of words in sentences. Can’t speak certain words.

Wernicke’s area

An area in the temporal lobe in the left hemisphere

Responsible for language comprehension

Encircles the auditory cortex

Leads to fluent aphasia if damaged - incoherent or made up words when speaking

S Case study evidence

Broca studied Leborgne. Known as “Tan” as he could only say the word tan.

In a post mortem there were lesions in the posterior of the frontal lobe in Left hemisphere only. Known as Broca’s area

Wernicke found lesions in a patient in the posterior of the temporal lobe in LH only. Known as Wernicke’s area, They had problems with speech understanding.

Supports both Broca’s and Wernicke’s area

S Dougherty

Gave 44 patients with OCD a cingulotomy to take away their cingulate gyrus (in the limbic system)

32 weeks after, a third had shown significant improvement in their OCD

14% had shown partial improvement.

Suggests that certain parts of the brain are linked to certain disorders.

W Dronkers

Language production may not be confined to Broca’s area alone.

Re-examined Leborgne’s brain and looked at other brains. Used MRIs.

There were lesions in Broca’s area as well as in other areas which may have been responsible for the language difficulties

Doesn’t fully support Broca’s area.

W D!ck and Tremblay

Reported that 2% of modern researchers think that language is controlled in Broca’s and Wernicke’s area.

Advances in brain imaging techniques like fMRI mean that neural processes can be studied with more clarity. Langauge function is distributed more holistically than was first thought.

Language streams have been identified in regions in the RH as well as subcortical regions like the thalamus.

Suggests that language may be more holistically organised and contradicts localisation theory