localisation of function in the brain Flashcards
What is localisation of function?
Functions e.g. movement, speech, memory, are performed in distinct regions of the brain (localised)
What 4 cortex’s are on BOTH sides of the brain?
What is this a form of (*expect auditory)? What is this?
Motor cortex
Somatsosensory cortex
Occipital lobe/visual cortex
Auditory cortex
Contralateral=Each hemisphere (left and right) of the brain controls the opposite side of the body
What 2 areas are ONLY on the LEFT side of the brain?
What is this a form of? What is this?
Broca’s area
Wernicke’s area
Hemisherically latralised=each hemisphere (left and right) of the brain is specialised to perform different functions
Right=Visuospatial tasks
Left=Language centres
What is a cortex?
Why is it folded?
Surface layer of the brain
Referred to as grey matter
Greater surface area
What is responsibility of the visual cortex (occipital lobe)?
What does damage lead to?
The brains visual processing center
Partial or complete loss of vision -‘cortical blindness’
Damage to one cortex>loss of vision in the opposite visual field -contralaterality
What is the responsibility of the motor cortex?
What does damage lead to?
Responsible for voluntary motor movement e.g. deciding to move your arm
Loss of muscle function, potentially paralysis is severe paralysis
Occurs on the opposite side of the body to the damage -contralaterality
What is the responsibility of the somatosensory cortex?
What does damage lead to?
Responsible for receiving sense impressions from around the body
Loss of sensation, loss of ability in recognizing objects by their feel -agnosia
Effects are in opposite side to damage
What is the responsibility of the auditory cortex?
What does damage lead to?
Recieves and processes sound information from ears
Cortical deafness, no damage to ear structure, but patient is unable to hear
What is the responsibility of Broca’s area (left hemisphere only)?
What does damage lead to?
Speech production
Difficulty producing fluent speech, speech is slow and effortful, speech has missing words>poor grammar -‘Broca’s aphasia’
What is the responsibility of the Wernicke’s area (left hemisphere only)?
What does damage lead to?
Speech comprehension
Difficulty understanding speech or written language, speech sounds fluent but lacks meaning -‘Wernicke’s aphasia’
What can damage to both Broca’s and Wernicke’s area lead to? What is this?
Global aspasia- inability to produce or understand speech
A strength of the localisation of function is that there is case study evidence, explain.
Critisise this.
Case study s demonstrates loss of functions if damage is caused to particular areas of the brain e.g. Broca’s and Wernicke’s case studies (aphasia’) Clive Wearing (amnesia)
Case studies are seen as unscientific
A strength of the localisation is that there is modern brain scanning techniques, explain.
Critisise this.
E.g. fMRI support research on language centres, showing activation in the regions associated when healthy ppts perform language tasks
Complex functions e.g. consciousness appear not to be localized at all, perhaps the correct way of arguing for the localiseed nature of the brain is dependant on function
What happened in Lashley’s study?
What did Lashley find?
50 rats ran a maze before and after areas of their brain cortex was destroyed
Found ability to successfully re-run the maze was affected by how much brain cortex was destroyed, not which areas
What does Lashely’s study suggest?
Higher cognitive processes e.g. learning, memory, are not localised, but distributed across the brain
The more brain destroyed>worse functioning becomes
