localisation of function and plasticity

Question 1

what is localisation of function?

Answer 1

functions such as movement, speech and memory and performed in distinct regions of the brain as opposed to the view that the brain acts holistically to perform functions

Question 2

functionally specialised brain areas

Answer 2

motor, somatosensory, visual and auditory cortices are on both sides of the brain
Broca and Wernicke’ area are found on left hemisphere

Question 3

what is hemispheric lateralisation?

Answer 3

each brain hemisphere is specialised to perform different functions
language centers in left
visuospatial tasks in right

Question 4

define contralateral

Answer 4

each brain hemisphere controls the opposite side of the body

Question 5

define cortex

Answer 5

surface layer of the brain
aka grey matter
contains mostly cell bodies and unmyelinated
folded for extra surface area for processing

Question 6

what is the visual cortex?

Answer 6

located in occipital lobe at the back of the brain
it is the brains visual processing center
each visual cortex receives information from the contralateral visual field

Question 7

damage to visual cortex?

Answer 7

leads to cortical blindness - partial or complete loss of vision
damage to one cortex leads to loss of vision in opposite visual field

Question 8

what is the motor cortex?

Answer 8

found at the back of the frontal lobe
responsible for voluntary motor movements

Question 9

damage to motor cortex?

Answer 9

results in loss of muscle function or paralysis
contralateral

Question 10

what is the somatosensory cortex?

Answer 10

found at the front of the parietal lobe
responsible for receiving sense impressions from around the body

Question 11

damage to somatosensory cortex?

Answer 11

leads to loss of sensation, ignoring areas of body, loss of ability in recognising objects by their feel
contralateral

Question 12

what is the auditory cortex?

Answer 12

located at the top of the temporal lobe
receives and processes sound information from ears

Question 13

damage to auditory cortex?

Answer 13

leads to cortical deafness - inability to hear but no damage to ear itself
contralateral

Question 14

what is Broca’s area?

Answer 14

located in bottom of left frontal lobe
responsible for speech production

Question 15

damage to Broca’s area?

Answer 15

leads to Broca’s aphasia (motor aphasia) - difficulty producing fluent speech - results in slow and effortful speech with missing words and poor grammar

Question 16

what is Wernicke’s area?

Answer 16

located in top of left temporal lobe (behind Broca’s area and auditory cortex)
responsible for speech comprehension

Question 17

damage to Wernicke’s area?

Answer 17

leads to Wernicke’s aphasia (sensory aphasia) - difficulty understanding speech and written language - results in fluent-sounding speech that lacks meaning

Question 18

what is the corpus callosum

Answer 18

bundle of fibres that enables communication between both brain hemispheres

Question 19

case study of TAN

Answer 19

Tan could understand spoken language but was unable to produce coherent words only ‘TAN’
Broca conducted a post-mortem examination on Tan’s brain and discovered that he had a lesion in the left frontal lobe
this led Broca to conclude that this area was responsible for speech production and any damage would result in slow and inarticulate speech

Question 20

case study of Phineas Gage

Answer 20

while working on a rail line he experienced a drastic accident in which a piece of iron went through his skull
Gage survived but experienced a change in personality e.g. increased anger
this supported the theory of localisation of brain function as it was believed that the area the iron stake damaged was responsible for personality