localisation of function in the brain Flashcards
what did scientists accept prior to paul broca & karl wernicke
- holistic theory of the brain
- argued for localisation of function (cortical specialisation)
- different areas of brain perform different tasks & involved with different parts of the body
what is the cerebrum divided into
2 hemispheres:
- left hemisphere controls right-hand side of the body & linked with language
- right hemisphere controls left-hand side of body
define lateralisation
some physical/physiological functions controlled/dominated by certain hemisphere
what is the cerebral cortex divided into
4 centres:
- frontal lobe
- parietal lobe
- occipital lobe
- temporal lobe
where is the motor area found & describe it’s role
- back of both frontal lobes
- controls voluntary movement on opposite side of body
- damage may result in loss of fine movements
where is the somatosensory area found & describe it’s role
- front of both parietal lobes
- sensory info from skin is represented
- separated from motor area by central sulcus
- amount of somatosensory area devoted to certain body part indicates its sensitivity
where is the visual area found & describe it’s role
- occipital lobes
- each eye sends info from RVF to RVC and LVF to LVC
- eg. damage to left hemisphere can cause blindness in RVF of both eyes
where is the auditory area found & describe it’s role
- temporal lobes
- analyses speech-based information
- damage may cause partial hearing loss
2 language centres
- broca’s area
- wernicke’s area
describe broca’s area
- paul broca identified area in left frontal lobe responsible for speech production
- damage causes broca’s aphasia = slow, laborious speech which lacks fluency
- eg. ‘tan’
describe wernicke’s area
- karl wernicke identified area in left temporal lobe responsible for language understanding
- could produce language but couldn’t understand it (fluent but meaningless speech)
- damage causes wernicke’s aphasia = produce nonsense words (neologisms)
AO3 +) evidence from neurosurgery that damage to areas of the brain are linked to mental disorders
E:
- cingulotomy involves isolating region called cingulate gyrus which has been implicated in OCD
- dougherty et al. (2002) reported on 44 people with OCD who’d had a cingulotomy
- post-surgical follow-up at 32 weeks showed ~30% met the criteria for successful response & 14% for
partial response
T: success of these procedures suggests behaviours associated with serious mental disorders are localised
AO3 +) evidence from brain scans supporting idea that everyday brain functions are localised
E:
- petersen et al. (1988) used brain scans to show how wernickes area was active in listening task & broca’s
area was active in reading task
- buckner & petersen (1996) conducted long-term memory studies which revealed semantic & episodic
memories reside in different parts of prefrontal cortex
- confirm localised areas for everyday behaviours
T: objective measures for measuring brain activity provide scientific evidence for localisation of many brain
functions
AO3 -) localisation theory challenged
E:
- lashley (1950) removed areas of cortex (10-50%) in rats learning route through a maze & found no area
proved to be more important in learning the route
- process of learning required every part of cortex (not particular area)
T: suggests higher cognitive processes (eg. learning) are not localised but distributed more holistically in brain
AO3 +) **phineas gage (case study)
E:
* accident caused most of left frontal lobe to be removed
* turned from calm/reserved to quick-tempered, rude & ‘no longer gage’
T: suggests left frontal lobe is responsible for regulating mood
HOWEVER: had no control prior to accident
