localisation of brain function

Question 1

what is the name of the ‘bridge’ between the two hemispheres of the brain? what is it?

Answer 1

-corpus callosum
-its a bundle of fibres that creates a acts as a communication pathway so the two hemispheres can exchange info

Question 2

what is the study of phineas gage?

Answer 2

railway worker who had a metal rod go through his chin and out his forehead, he recovered and only lost sight in his left eye, but he had changed psychologically
before, he was described as calm and well-mannered, after he was hostile and rude using vulgar language that he didn’t use prior to the injury
Dr Harlow believed there was localisation, and the damaged area was associated with planning, reasoning and control

Question 3

what is hemispheric lateralisation?

Answer 3

the tendency for neural functions and cognitive functions to be specialised to one side of the brain
(the division of functions between the two hemispheres)

Question 4

what does it mean for the brain to be contralateral?

Answer 4

parts of the left hemisphere deal with the right side of the body and vice versa

Question 5

what does the left hemisphere do?

Answer 5

-language processing
-Broca’s area
-Werwick’s area

Question 6

what does the right hemisphere do?

Answer 6

-recognises emotions
-spatial relationships
-detail and patterns

Question 7

what is the motor centre? what are the five motor centres?

Answer 7

brain area associated with control of complex movements, eg walking
-motor cortex
-somatosensory centres
-visual centres
-auditory centres
-language centres

Question 8

what is the motor cortex?

Answer 8

-where movement is centred
-sends messages to the muscles via the brain stem and spinal cord
-important for complex movement, not so much basic actions
-different areas within it that control specific parts of the body
-the complexity of the movement controls the number of neurons
-when motor cortex instructs an outcome the spinal cord and other areas co-ordinate all the various areas of the body into a movement

Question 9

what are the three areas of the brain involved in movement?

Answer 9

-the brain and spinal cord (co-ordinates the movement)
-premotor cortex (plans the movement)
-prefrontal cortex (stores sensory info prior to a movement and works out the probably outcome)

Question 10

what are somatosensory centres?

Answer 10

-refers to the sensations of the body
-lies next to the motor cortex
-perceives touch, the amount of neural connections needed decides the amount of somatosensory cortex required for that area of the body

Question 11

what are visual centres?

Answer 11

-primary visual cortex:
-brain has 2 visual cortices, one in each hemisphere
-primary visual cortex is in the occipital lobe (back of the brain) and is seen as the main vision centre, specifically has an area called V1 which is necessary for visual perception
-visual info is transmitted across 2 pathways, one has the components of the visual field, the other involved in the location within the visual field
-overgaard et al 2008

Question 12

overgaard et al 2008

Answer 12

-GR had been having headaches for 3 months, suddenly got worse, she got blindness in her right visual field
-CT scans showed a haemorrhage in the left occupational lope
-brain started to swell, drain put in to get rid of fluid
-although she had no injuries to her eyes, the brain was damaged in the visual cortex, meaning she was cortically blind
-when asked to detect letters on a screen she couldn’t identify the letter but reported an ‘awareness of something’ despite seeing nothing
-suggests there may be 2 types of vision, one conscious the other unconscious

Question 13

what are auditory centres?

Answer 13

-primary auditory cortex:
-human brain has 2 primary auditory cortex, one in each hemisphere
-receives info from both ears via two pathways that transmit info about what the sound is and where its coming from
-info from right ear goes primarily to left hemisphere
-if primary auditory cortex is damaged it doesn’t cause total deafness, but sounds that require complex processing (eg music) can no longer be heard

Question 14

what are language areas?

Answer 14

Broca’s and wernicke’s areas
-both found in the left hemisphere in most people, and is where language processing takes place

Question 15

what is Broca’s area?

Answer 15

-the brain area associated with production of speech
-not all words are equally affected by damage; nouns and verbs seem unaffected, but other classes like prepositions and conjunctions can’t be spoken
-domanski 2013

Question 16

domansci 2013

Answer 16

-leborgne had epilepsy, he lost his ability to speak (apart form the word tan) and was hospitalised at 30, until he died in 1861 at 51
-at the hospital he was treated by Paul Broca, who conducted a post-mortem examination of his brain, finding a lesion on the left temporal lobe. since this was the only area with damage, he said this was the responsible area for speech production

Question 17

what is wernicke’s brain area?

Answer 17

-the area associated with the comprehension of language
-1874 - wernicke found that ps who had damage in an area close to the auditory cortex had specific language impairments, including an inability to comprehend language and anomia (struggling to find the word you need)
-but wernicke noticed these people had fluent speech when they could access the words

Question 18

research on brain areas

Answer 18

-Heller and levy 1981 - a photo of a face split in half (half happy half neutral), the half on the left was the one recognised by patients, suggesting the right hemisphere is dominant in recognising emotions
-fink et al 1996 - if ps were asked to look at a picture and identify small detail, there was a greater level of activity in the LH than if they looked at the pic all together which was RH, supporting the idea that the LH focuses on details in the visual field while RH focuses on overall patterns

Question 19

evaluate brain areas

Answer 19

-holistic theory of the brain functions says localisation is incorrect - lashley 1950 looked at rat’s brains and found no area involved in memory, it was all over the brain
-evidence from case studies seems to indicate there’s both localisation and lateralisation of function. if functions were spread out there wouldn’t be specific details such as loss of speech function
-gender differences exist, females have larger Broca and wernicke areas
-rehabilitation working could argue against lateralisation and localisation, as if there were task-specific areas there would be no brain plasticity

Question 20

what is split-brain research?

Answer 20

-studies of the brain involving the separation of hemispheres, after surgery for severe epilepsy which cannot be controlled by drugs, allowing assessment of the functional roles of each hemisphere

Question 21

what is the link between the two hemispheres called?

Answer 21

the corpus callosum

Question 22

what was found in research conducted by nebes 1974?

Answer 22

-certain unfamiliar functions like stringing beads couldn’t be done, but familiar actions like tying shoe laces could
-first few weeks after surgery the hemispheres act separately, making the person feel like 2 people in one body (LH takes control of situations and suppresses interference from RH by using smaller pathways)
-sometimes the hemispheres co-operate with each other, (eg left visual field is shown a colour, RH sees it, LH cannot articulate the colour, so when asked what it is they cannot answer, can guess, then the RH shows its wrong by prompting a frown)
-some ps use strategies like turning their head to both hemispheres see everything

Question 23

what is alien hand syndrome?

Answer 23

-(eg) Byrne had split-brain surgery, following it her hand acted on it’s own accord, shows how movement is lateralised into each hemisphere