Localisation of Brain Function Flashcards
what do the cerebral hemispheres do?
controls higher functions such as memory, vision and hearing
linked together by a bundle of nerve fibres
different functions can be allocated to each hemisphere
what is the holistic theory?
the idea that all parts of the brain are involved in the processing of thought and action
what happened to phineas gage?
in 1848 he dropped a tamping iron onto the rock causing an explosion to ignite and hurl a metre length pole into his head
went through his left cheek, passed behind his left eye and through his skull
took a portion of his left frontal lobe
his personality was effected
limitations of phineas gage?
unique case so not generalisable
lacks validity as it was a long time ago
strength of phineas gage?
suggested the frontal lobe is responsible for regulating mood
what is lateralisation?
the idea different hemispheres control different functions
what is the cerebral cortex?
outer layer of both hemispheres
3mm thick
separates us from other animals as it is much more developed in humans
what does the frontal lobe do?
motor area
controls voluntary movement in opposite sides of the body
damage results in loss of fine movements
which hemisphere is the frontal lobe located?
it is in both hemispheres
where is the parietal lobe?
at the front (somatosensory cortex)
what is the central sulcus?
a ‘valley’ that separates the somatosensory area and the motor area
what does the brain stem do?
links to the spinal cord
what does the cerebellum do?
important for coordinating of movement and balance
damage can result in poor coordination and clumsiness. skills such as writing would be difficult without it
what is the parietal lobe (somatosensory area)?
where sensory information from the skin is represented
the amount of somatosensory area devoted to a particular body part denotes its sensitivity
where is the occipital lobe located?
at the back of the brain
what is the occipital lobe?
visual cortex
what does the occipital lobe do?
each eye sends information from the right/left visual field to the left/right visual cortex
this means damage to the left hemisphere, for example, can produce blindness in part of the right visual field of both eyes
what is the temporal lobe?
auditory area
what does the temporal lobe do?
analyses speech based information
what does damage to the temporal lobe produce?
may produce partial hearing loss
where is broca’s area?
left frontal lobe
what is broca’s area responsible for?
speech production
what side of the brain is language restricted to?
left side
what is broca’s aphasia?
slow, lacking in fluency speech
what happened to patient tan (broca)?
went to hospital 21 years prior to meeting broca for paralysis in the right side of his body due to advancing gangrene
could only say ‘tan’
met broca in 1861 and died shorty after, but not before giving his consent for a post-mortem examination
autopsy showed a mysterious legion in his left frontal lobe which broca thought was the reason for his aphasia
caused broca’s aphasia
what happened to lazare lelong (broca)?
experienced similar speech deficits to patient tan
autopsy showed the same damage in the left frontal lobe
what did broca think the lower part of the frontal lobe was responsible for?
speech production
where is wernicke’s area?
left temporal lobe
what is wernicke’s area responsible for?
language comprehension
what is wernicke’s aphasia?
produces neologisms (nonsense words)
when did wernicke study his patient?
1873
what did wernicke’s patient’s autopsy show?
lesion in his left temporal lobe
what did wernicke’s patient have wrong with him?
only spoke gibberish
what are the strengths of localisation of brain function?
evidence from brain scans - Peterson et al (1988)
neurosurgical evidence - Dougherty et al (2002)
case study evidence (phineas gage etc)
what did Peterson et al (1988) study?
used brain scans to demonstrate how wernicke’s area was active during a listening task and broca’s area was active during a reading task
what did Dougherty et al (2002) study?
reported on 44 OCD patients who had undergone a cingulotomy. at post-surgical follow up after 32 weeks, a third had met the criteria for a successful response, and 14% a partial reponse
what are the limitations of localisation of brain function?
Lashley (1950) suggests holistic theory
existence of plasticity - law of equipotentiality
what is Lashley’s law of equipotentiality?
surviving brain circuits can ‘chip in’ so the same neurological action can be achieved
