localisation of function in brain Flashcards
what is localisation of function?
Broca and Wernicke
different areas of brain responsible for specific behaviours, processes or activities
if certain area damaged- function associated also affected
hemispheres of brain
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
what is the cerebral cortex (outer layer of hemispheres) subdivided into?
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
motor area
at back of frontal lobe (both hemispheres)
controls voluntary movement in opposite side of body
damage- loss of control over fine movements
somatosensory area
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
visual area (cortex)
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
auditory area
part of temporal lobes
analyses speech-based info
damage- partial/complete hearing loss
language centres of brain
language restricted to left side of brain in most people
Broca’s area
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’
Wernicke’s area
area in left temperable lobe
responsible for language comprehension
damage- Wernicke’s aphasia (nonsense words/neologisms as part of speech content)
strength- evidence from neurosurgery
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
strength- evidence from brain scans
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
however- Lashley brain study
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
criticism- language localisation can be questioned
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