Localisation of function Flashcards
What is localisation OF?
The theory is that different areas of the brain are responsible for specific behaviours processes or activities.
What was the belief prior to Wernicke and Broca’s discovery?
Holistic theory of the brain- all parts of the brain were involved in processing of thought and action
What are the hemispheres of the brain?
The cerebrum is split into two symmetrical halves called the left and right hemisphere.
What is lateralisation?
Some of our functions are dominated by a specific hemisphere
What are the lobes of the brain and where are they located? (Draw it)
Frontal - front
Parietal- behind frontal (upper middle)
Occipital- very back
Temporal- underneath frontal and parietal
What are the four areas and where are they?
Motor area, frontal lobe (both hemispheres)
Somatosensory area, parietal (both)
Visual area, occipital
Auditory area, temporal
What is the jobs of the four areas?
Motor- controls voluntary movement in the opposite side of the body, damage may result in loss of fine movements
Somatosensory- Sensory information from the skin (heat, touch, pressure)
Visual- sends info from one visual field to opposite cortex
Auditory- analyses speech based info
What is the Broca’s area responsible for and what does damage to it result in?
Responsible for speech production (in left frontal lobe) damage causes Broca’s aphasia and like “tan” you have problems with prepositions lacking in fluency
What is the Wernicke’s area responsible for and what does damage to it result in?
Responsible for language comprehension (in left temporal lobe), damage results in Wernickes aphasia making people produce nonsense words (neologisms)
Brief evaluation of LOF?
- Evidence from neurosurgery: damage of areas can be linked to mental disorders
- Evidence from brain scans: everyday functions are localised BUT Lashley
- Language may not ONLY be localised to B + W
What are strengths of LOF?
Damage to the areas can be linked to mental disorders through neurosurgery as a last resort for treatment, cingulotomy involves isolating cingulate gyrus which implicates OCD. Dougherty et al reported on 44 people with OCD who underwent this surgery 30% were successful 14% partial response. Serious MH is localised
Brain scans, Petersen et al brain scans showed Wernicke’s area was active during a listening task and Broca’s during a reading task. Buckner and Petersen found episodic and semantic reside in different parts of pre frontal cortex. HOWEVER, Lashley’s rats despite removal of cortex where able to learn route before and after no part was more important
What are weaknesses of LOF?
Language may not just be localised to B+ W areas. Dick and Tremblay found only 2% of modern researchers think language is completely controlled by these. More clarity in brain scans has meant language function is distributed more holistically then before such as subcortical regions like the thalamus. Contradicts localisation, holistic?
