Localisation of function in the brain Flashcards
What is the holistic theory
All parts of brain involved in processing of thought and action
-Generally supported before theory of LOF/Phineas Gage
What is localisation of function
Broca/Wernicke: different parts of brain perform different tasks in different parts of the body
-So specific are damaged= function associated damaged
How is the cerebrum divided
Into 2 symetrical halves: left/right hemisphere
What is lateralisation
Specific functions controlled by particular hemisphere
-Left side of body controlled by right-hemisphere
-Right side controlled by left hemisphere (e.g language)
What is the cerebral cortex
Outer layer of both hemispheres
-Divided into 4 lobes
What are the four lobes of the cerebral cortex
Frontal
Parietal
Occipital
Temporal
What is a lobe
Part of an organ that is separated from the rest
-Each associated with different functions
Function of the motor area
Controls voluntary movements on the opposite side of the body
Where is the motor area located
Back of the frontal lobe in both hemispheres
Damage to the motor area results in?
Loss of control over fine movements
Damage to the motor area results in?
Loss of control over fine movements
Location of somatosensory area
Front of both parietal lobes
Function of somatosensory area
Receive sensory info from skin
-Amount of area devoted to particular part body part= sensitivity
e.g face/hands receptors= + 50%
Where is the occipital lobe located
Back of the brain
Function of occipital lobe
Receives visual info
Damage to left hemisphere
Eye sends info from right visual field to left visual cortex/left visual field to right visual cortex
So could= blind in part of right visual field in both eyes
Function of temporal lobe
Houses auditory area-analyses speech-based information
What does damage to the temporal lobe result in
Hearing loss
Damage to Wernicke’s area= less ability to comprehend language
What is Broca’s area
Small area in left frontal lobe associated with speech production
What does damage to Broca’s area result in
Broca’s aphasia= slow speech lacking in fluency
e.g Tan could only say word “tan”
What is Wernicke’s area
Region in left temporal lobe responsible for language understanding
What does damage to Wernicke’s area result in
Wernicke’s aphasia= fluent speech but meaningless
Strength of localisation theory
Knowledge can be used to treat mental disorders
-e.g neurosurgery like cingulotomy in treating OCD- Dougherty et al found 30% patients had successful response
-Suggests behaviours associated with serious mental disorders may be localised
Strength 2 of localisation theory
Evidence from brain scans
e.g Petersen et al found Wernicke’s area active during listening task/Broca’s active during reading
So scientific evidence that many brain functions for everyday behaviours are localised
Weakness of localisation theory
Lashey (1950): Removed areas of cortex in rats who were learning a maze
-Process required every part not particular area
Suggests higher cognitive processes distributed in more holistic way
2 Weakness of localisation theory
Only 2% researchers think brain is controlled by Broca’s/Wernicke’s area
-FMRI shows language functions distributed holistically (e.g “language streams”)
Contradicts localisation theory
Strength 3 of localisation theory
Case study evidence
-e.g Phineas Gage: explosion took most of frontal lobe- survived but personality chnaged
-So frontal lobe maybe regulates mood
HOWEVER:
case studies not generalisable/could be researcher bias
