Localisation of function BP Flashcards
localisation of function
different areas of the brain are responsible for specific behaviours, processes or activities
motor area
a region of the frontal lobe involved in regulating movement
Somatosensory area
an area of the parietal lobe that processes sensory information such as touch
visual area
a part of the occipital lobe that receives and processes visual information
auditory area
located located in the temporal lobe and concerned with the analysis of speech-based information
Broca’s area
an area of the frontal lobe in the left hemisphere, responsible for speech production
Wernicks’s area
an area of the temporal lobe in the left hemisphere, responsible for language comprehension
what did Broca and Wernicke find?
- specific areas of the brain are associated with physical and psychological functions
- If a specific part of the brain is damaged then the function associated with that part will also be damaged
hemisphere of the brain
Two symmetrical halves (left and right hemisphere)
Lateralisation
when each hemisphere controls certain functions
Eg language is left hemisphere
Control of activity
Activity on the left is controlled by the right hemisphere and vise versa
cerebral cortex
the outer layer for both hemispheres
What are the 4 lobes that the cerebral cortex is divided into?
- Frontal
- Parietal
- Occipital
- Temporal
lobe
part of an organ that is separate from the rest
Motor area (back of frontal lobe)
controls voluntary movement in opposite side of body, damage here will disrupt control over fine movements
Somatosensory area (front of both parietal lobes)
separated from motor area by the central sulcus, where sensory information is processed, the amount of somatosensory area devoted to a body part relates to its sensitivity
Visual area (occipital lobe)
damage to left hemisphere can produce blindness in the right visual field of both eyes
Auditory area (temporal lobes)
analyses speech-based information, damage can lead to hearing loss
language is restricted to the …
left side of the brain
Broca- identified a small area in the left frontal lobe, which is responsible for …
speech production
Damage to Broca’s area- causes Broca’s aphasia, which is characterised by?
slow and laborious speech, lacking in fluency
Who is Broca’s most famous patient?
‘Tan’ (only word he could say)
What do people with Broca’s aphasia have difficult with?
preposition and conjunctions
Wernicke described ?
people who had no problem producing language, but severe difficulty understanding it (e.g. speech was fluent but meaningless)
What and where was Wernicke’s area?
responsible for language understanding
left temporal lobe
What happens in Wernicke’s aphasia?
produce nonsense words (neologisms)
strengths
Evidence from neurosurgery
Evidence from brain scans
limitations
Counter evidence for localisation
Language localisation questioned
Evidence from neurosurgery
I:
strength
I: last resort method for treating mental disorders eg cingulotomy involves isolating the cingulate gyrus (OCD implications)
Evidence from neurosurgery
D:
strength
D: Dougherty et al reported on 44 people with OCD, who had undergone a cingulotomy- after a post-surgical follow up 32 weeks later, 30% had met the criteria for successful response to the surgery vs 14% for partial response
Evidence from neurosurgery
E:
Strength
E: Success from procedures suggest that behaviours associated with serious mental disorders may be localised
Counter-evidence for localisation
D:
limitation
D: Lashey removed areas of the cortex (between 10-50%) in rats that learnt the route through a maze
No area was more important than any other area in terms of the rats’ ability to learn the route
Counter-evidence for localisation
E:
limitation
E: The learning process required every part of the cortex
This suggests that higher cognitive processes, i.e: learning, are not localised but distributed in a more holistic way
Evidence from brain scans
I:
strength
I: Peterson et al 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
Evidence from brain scans
D:
strength
D: A review of LTM by Buckner and Peterson reveals that semantic and episodic memories reside in different parts of the prefrontal cortex
Evidence from brain scans
E:
strength
E: Objective methods for measuring brain activity have provided accurate scientific evidence that brain functions are localised
Language localisation questioned
I:
limitation
I: Dick and Tremblay found only 2% of researchers believe language is controlled completely by Broca’s and Wernicke’s areas
Language localisation questioned
D:
limitation
- Advances in scanning techniques mean that neural processes can be studied with more clarity (e.g: fMRIs)
Language localisation questioned
E:
limitation
- Language streams have been identified across the cortex, including regions in the right hemisphere, and subcortical regions
- Suggests language is organised holistically in the brain, contradicting localisation theory
Evaluation extra: Case study evidence-
- Phineas Gage: whilst working with explosives, a metal pole passed through his eye, into his skull (removing a portion of his left frontal lobe)
- Frontal cortex= planning, reasoning, control
- Gage’s personality changed- he became rude and hostile
- Supports localisation theory
