Hemispheric lateralisation and split-brain research

Question 1

what is hemispheric lateralisation?

Answer 1

two halves of the brain are functionally different and certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other

Question 2

what is an example of hemispheric lateralisation?

Answer 2

• language , Broca’s area in the left frontal lobe and Wernicke’s area in the left temporal lobe
• language is lateralised

Question 3

what can right hemisphere only produce?

Answer 3

• rudimentary words and phrases but contributes emotional context to what is being said
• led to the suggestion that the LH is the analyser whilst the RH is the synthesiser

Question 4

what is an example of a function that is not lateralised?

Answer 4

• vision, motor and somatosensory areas appear in bothe hemispheres

Question 5

what does the motor area have?

Answer 5

• has contralateral wiring
• the RH controls movement of the left side of the body whilst he LH controls movement of the right

Question 6

what does vision have?

Answer 6

• contralateral and ipsilateral
• each eye receives light from the LVF and RVF
• LVF of both eyes is connected to the RH and the RVF of bothe eyes is connected to the LH

Question 7

what does the contralateral and ipsilateral enable?

Answer 7

• visual areas to compare the slightly different perspective from each eye and aids depth perception

Question 8

what else has a similar arrangement to the visual areas?

Answer 8

• auditory input to the auditory area and the disparity from the two inputs helps us locate the source of sounds

Question 9

what is ‘split-brain’?

Answer 9

• severing the connections between the RH and LH, mainly the corpus callosum
• surgical procedure to reduce epilepsy

Question 10

what does split brain research study?

Answer 10

how the hemispheres function when they can’t communicate with each other

Question 11

what was the aim of Sperry’s research?

Answer 11

• devised a system to study how two separated hemispheres deal with e.g. speech and vision

Question 12

what is the procedure of Sperry’s research?

Answer 12

• 11 people who had split-brain operation were studied by an image being projected to a ppts RVF (processed by LH) and image could be projected to LVF (processed by the RH)
• in ‘normal’ brain corpus callosum would immediately share the info between both hemispheres giving a complete picture of visual world
• however, presenting image to one hemisphere of split brain ppt meant that info cannot be conveyed from that hemisphere to the other

Question 13

what were the finding of Sperry’s research?

Answer 13

• when picture of object was shown to ppts RVF, ppt could describe what was seen, but could not if object was shown to LVF (said there was nothing there)
• connected brain = messages from the RH are relayed to the language centres in the LH (not possible in split-brain)