hemispheric lateralisation and split-brain research

Question 1

hemispheric lateralisation

Answer 1

the 2 halves of the brain are functionally different

Question 2

localised

Answer 2

some functions are localised and appear in both Left and right hemispheres

Question 3

what hemisphere is language controlled by

Answer 3

left

its the analyser

Question 4

what hemisphere is facial recognition and spatial comprehension controlled by

Answer 4

right

its the synthesiser

Question 5

contralateral

Answer 5

e.g in the motor area RH controls Left side of the body

Question 6

corpus callosum

Answer 6

the 2 hemispheres are connected by the CC - this allows information received from one hemisphere to be sent to the other hemisphere

e.g info from the RVF goes to the LV cortex
= info passes through the corpus callosum

Question 7

split brain research - treatment for severe epilepsy

Answer 7

cut through the bundle of nerve fibres that formed the corpus callosum

used to treat severe epilepsy to reduce the electrial strom across hemispheres 3

Question 8

split brain research - sperry

Answer 8

11 split brain patients (had their corpus callosum severed)

particiapnts covered one eye and looked at a fixed point on a screen
pictures were shown onto the left or right side of the screen quickly to not allow eye movement

If the picture was shown in the RVF PPTS, they could write or say what it was (bc it transfers to the LH that does language)

if image was shown to LVF = couldn’t say or write but could select a corresponding object with left hand

= diff areas of brian specialise in diff functions

usually info in RH can be processed by left
In split-brain = it can’t happen, so the info going into RH can’t be converted into language at all

Question 9

hemispheric lateralisation AO3 - strength is evidence of lateralised brain functions in ‘normal brains’.

Answer 9

E - PET scans shown when ‘normal’ participants attend to global elements of an image, the RH is more active. When required to focus on finer detail the specific areas of the LH tend to dominate
E - this suggests that hemispheric lateralisation is a feature of the normal brain as well as split-brain

Question 10

hemispheric lateralisation AO3 - limitation: the idea of analyser v synthesiser brian may be wrong

Answer 10

There may be different functions in RH and LH, but research suggests people do not have a dominant side

Nielsen et al analysed 1000 brain scans finding people did use certain hemispheres for certain tasks but no dominance

suggests that the notion of right or left brained people is wrong

Question 11

split brain research AO3 - strength is support from more recent split-brain studies

Answer 11

E - Luck et al showed that split-brain participants are better than normal controls. In the normal brain, the LH’s superior processing abilities are ‘watered down’ by the inferior RH
E - this supports Sperry’s earlier findings that the ‘left brain’ and ‘right brain’ are distinct in terms of functions and abilities

Question 12

split brain research AO3 - limitation is that casual relationship are hard to establish

Answer 12

E - in Sperry’s research the behaviour of split-brain participants was compared to a neurotypical control group. However, none of the control group had epilepsy. Any differences between the groups may be due to epilepsy no the split-brain (a confounding variable).
E - this means that some of the unique features of the split-brain participants cognitive abilities might have been due to their epilepsy.