localisation of function Flashcards
What is meant by the term localisation of function?
Localisation of function refers to the principle that specific functions have specific locations within the brain.
What is the motor cortex responsible for?
responsible for the generation of voluntary motor movements.
Where is the motor cortex located within the brain?
posterior of the frontal lobe
do both sides of the brain have a motor cortex and what do they cotrol?
Both hemispheres have a motor cortex - each side control over the opposite body side
What does damage to the motor cortex cause?
cause loss of muscle function / paralysis on opposite side of body
what does the somatosensory cortex do?
detects sensory events along the postcentral gyrus
where is the somatosensory cortex located within the brain?
In the parietal lobe
DO both hemispheres have a somatosensory cortex and what do they porcess?
Yes
Process touch , pain , heat presure and produce a sensation within the relative area
what does damage to the somatosensory cortex cause?
loss of sensation in opposite side of the body
Where is the visual cortex found?
in the occipital lobe
How does processing within the visual cortex occur?
- Processing begins in retina, where light hits photoreceptors
- The optic nerve transmits the impulse to the thalamus
- the thalamus relays the information to the visual cortex for processing
do both hemispheres have a visual cortex and where to they receive imput of information from?
Yes
They receive informatio from the opposite side of the visual field
visual cortex processing flow chart
Retina → optic nerve → thalamus → visual cortex (co-ordinates a response)
where is the auditory cortex located?
Temporal lobe
What is the auditory cortex responsible for?
sound processing
where does the auditory cortex receive information from?
the cochlea in the inner ear
How does the auditory cortex process information?
- Information received by cochlea in the inner ear → converts soundwaves to nerve impulses which travel to the brain
- When it reaches the brain stem information is decoded such as the intensity of the sound and duration
- The nerve impulse travels to the thalamus - relay station for further processing
Auditory cortex processing flow chart
cochlea -> coverts soundwaves - nerve impulses –> travel to brain –> reaches brain stem where information is decoded such as intensity –> nerve impulse travels to thalamus (relay station for later processing)
Broca’s area where is it located
posterior left frontal lobe
What is broca’s area acossiated with ?
language production
How did Broca come to his findings?
Using post mortems of patient TAN who could only say the word TAN and identidied a lesion on broca’s area
what is Broca’s aphasia ?
is a conditioned characterised by very limited and clumsy speech and writing
Where is Wernicke’s area located?
Located in left temporal lobe
How did wernicke’s area find out the research?
Examined patients but his could speak random noises but not understand language
* Therefore he proposed that language involves separate motor and sensor regions located in different cortical regions
what is the neural loop between Broca and Wernicke’s area?
someone struggle comprehending language they may also have some difficulties with speech (interlinked)
What is Wernicke’s aphasia?
conditioned characterised by limited understanding of language and inablity to form coherent speech
AO3 Strengths
- Aphasia studies
Broca / wernicke’s research add understanding to aphasia which many suffer from
Expressive aphasia = impaired ability to produce language
Receptive aphasia = inability to understand language / extract meaning from words
Pioneered a greater volume of research / expansion of knowledge for speech and language comprehension issues / what can be done for rehabilitation
- Knowledge of functionality
Allowed for greater knowledge and understanding to be able to treat - Real world application
Through understanding the prolonged / immediate impacts → in 1840s wanted to understand the behavioural
Phineas Gage → had a rod through his skull through left cheek and up through his frontal lobe
Survived \
Had long term personality disorder/ unable to follow through with plans
Case study highlighted able to experience damage and be able to live / function relatively normally after
Highlights the frontal lobes are responsible for personality and reasoning - supports LOF knowledge
Limitations
- LASHLEY
Localisation does not exist for simple processing not for higher functions → reductionist
Did research on rats causing lesions found that despite damage to specific areas → still continued to function socially,physically
When damage in brain other areas will compensate (equipotentiality) → localisation of function is reductionist
Though if fully destroyed the part of the brain other areas unable to compensate
- Consider LOF or more interest in communication across brain
Bejerine → found if someone lost ability to read due to the damage between visual cortex and wernicke’s area
Suggests that complex processing build up then suggesting simple LOF but the damage to connection between these structures may cause impairments
LOC may not be as important but identifying the connectivity is more important
- Is language confined to Brocas?
DRONKER →reviewed preserved of two Broca’s patients
TAN / Lazare Lelong using MRI
Found other areas were damaged as well that MAY have contributed to speech impairments
Damage to Broca’s area rarely results in severe damage suggesting it is far more complex
So new techniques shows the lesion was not the only thing impacting other damages areas may have been contributing to this loss of speech
- Broca
Only one or two patients → lacking generalisability / reliability
Brocas less specific → lacks scientific credibility - Individual differences → unable to assumer
Baveller - found unique behaviour in individuals finding these varied in the frontal / temporal and occipital lobes
Research found gender differences in size f Broca/ Wernicke’s area
