localisation of function in the brain Flashcards
what does localisation of function in the brain mean ?
-Refers to the belief that specific areas of the brain are responsible for different behaviours, cognitive processes or activities.
- it contradicts the earlier holistic theory of the brain.
fill in the names of each part of the brain.
going clockwise
1.primary somatosensory cortex
2.primary visual cortex
3.wenickes area
4.primary auditory area
5.brocas area
6.primary motor cortex
what is the visual cortex ?
- the primary visual centre in the brain
- located in the occipital lobe.
- responsible for processing different types of visual information like colour, shape or movement.
- it spans both hemispheres of the brain. Right hemisphere receives information from left hand side of the visual field and visa versa.
- This means damage to the right hemisphere produces blindness in left visual field in both eyes.
what is the auditory cortex ?
-its concerned with hearing and is located within the temporal lobes of both sides of the brain.
- processes pitch and volume
- damage may produce hearing loss, more extensive the damage, more extensive the hearing loss
- damage to specific area of the temporal lobe e.g. Wernicke’s area may effect ability to understand language.
what is the motor cortex( voluntary movements)?
- Responsible for voluntary motor movements.
- located in the frontal lobe along a bumpy region known as the precentral gyrus.
- both hemispheres have a motor cortex, controlling the muscles on the opposite side of the body.
- different parts of the motor cortex control different parts of the body and the regions are located locally next to each other - e.g region that controls the motor movement of a leg will be next to the region that controls the foot and so on.
- damage to area may result in loss of control over fine movements.
What is the somatosensory cortex ?
- detects sensory events happening in different regions of the body.
- in the parietal lobe of the brain, along the post central gyrus , which is part of the cortex dedicated to the processing of sensory information related to touch.
- using sensory info from the skin, the somatosensory cortex produces sensations of touch ,pressure, pain and heat which it localises to specific body regions.
-both hemispheres have a somatosensory cortex, cortex on one side of the brain receiving sensory information from opposite side of the body. - damage to somatosensory cortex results in decreased sensitivity e.g not being able to identify objects by touch.
what is Broca’s area?
- Broca’s area is critical for speech production.
- Broca’s area is in the posterior portion of the left frontal lobe only.
- Damage to the area caused Broca aphasia, which is characterised by speech that is slow, lacks fluency as seen in “Tan” one of Broca’s patients.
What is Wernicke’s area ( understanding language )?
- responsible for language comprehension
- in the left temporal lobe
- Wernicke worked with patience who had no problem producing speech but severe difficulty understanding it, fluent but meaningless.
Damage to the area results in Wernicke’s aphasia, where patients produce nonsense words as their normal speech.
what is the supporting evidence from brain scans by peterson et el that supports brain localisation theory?
P- A strength of the localisation of function theory is it supported by research.
E- Peterson et al used brain scans to demonstrate how Wernicke’s area was active during listening tasks and Broca’s area was active during a reading task.
E- this is a strength as it provides evidence that specific areas of the brain are responsible for different behaviours, cognitive processes and activities.
a strength of peterson et els research is that its highly empirical. Explain why this supports brain localisation theory?
P- a strength of Peterson et als research is that it is highly empirical.
E- brain scans provide objective evidence to show that different areas of the brain were active during listening and reading tasks.
E- this is a strength because these findings provide verifiable evidence for localisation of function
what is the case study of brocas area and “TAN”
Broca studied a patient who had suffered brain damage that resulted in him only being able to say one word” tan “.He could easily understand speech, instructions and what was being said to him. Tan died a week after Broca met him, so he conducted an autopsy on his brain and discovered extreme damage in his left frontal lobe. Over the next 4 years Broca found 12 more cases where the symptoms of tan were similar .In all cases autopsy’s revealed damage in the base of the left frontal lobe .Broca therefore concluded that this area known as Broca’s area is responsible for the production of speech.
Why is the case study of Phineas Gage a strength for the theory of localisation of function ?
P- A strength of localisation of function theory is that it is supported by the case study of Phineas Gage.
E- Phineas gage was involved in an explosion which hurled a meter length pole through his cheek and eye and exited from the top of his head destroying most of him left frontal lobe. He survived but his personality changed from being calm to someone with a short temper and rude.
E- This is a strength of localisation of function theory because this case study suggests the frontal lobe is responsible for regulating mood.
What is a limitation of using the case studies of tan and phineas gage as evidence to support localisation of function theory?
P- Case studies are individualistic so unrepresentative .This is because there is no certainty that they are typical of the whole population.
E- therefore we cannot be certain that the localisation of brain function demonstrated by tan and Phineas gage would happen to other human beings.
E- These studies don’t prove that brain function is localised in the way the theory suggests.
L- However, because Broca also found 12 other cases that demonstrated localisation of function this would suggest that there is reasonable evidence that specific areas of the brain are responsible for different behaviours, cognitive processes and activities.
lashley rat
What is contradictory evidence against the theory of localisation of function in the brain?
P- A limitation of the theory of localisation of function in the brain is that there is evidence to suggest that the theory is not correct.
E- Lashley removed areas of the cortex (between 10%-50%) in rats, which were learning a maze.No area was proven to be more important than any other in terms of the rats ability to learn the maze.The process of learning appeared to require every part of the cortex not specific areas.
E- This contradicts the theory of localisation of function in the brain because it suggests that some functions such as learning are too complex to be localised and require the whole brain.
What is a conrtadictory point to lashleys finding on function of the brain not being localised?
P- a limitation of lashleys work is that it is extrapolous. We cannot be sure that findings from studies using rats can be applied to humans.
E- this is because human brains are much more sophisticated than rats.
E- therefore it does not prove that the findings are true for humans.
