Biopsychology - Hemispheric lateralisation and split brain research

Question 1

what is hemispheric lateralisation

Answer 1

• two hemispheres of the brain are functionally different
• certain mental processes and behaviours are controlled by one hemisphere over the others

Question 2

what is the left hemisphere

Answer 2

• main language centres - Broca and Wernicke’s
• controls movement on the right

Question 3

how is vision both contralateral and ipsilateral

Answer 3

• each eye relieves light from LVF and RVF
• LVF of both eyes is connected to the RH
• RVF of both eyes is connected to the LH

Question 4

what was Sperry’s research

Answer 4

• 1968
• devised a system to study how two separated hemispheres deal with speech and vision

Question 5

what was Sperry’s procedure

Answer 5

• 11 people who split brain surgery studied
• image projected into pps RVF and same or different image in the LVF 7
• ‘normal’ brain the corpus callosum would share information between both hemispheres

Question 6

what did Sperry find

Answer 6

• picture of an object shown in RVF could describe what was seen
• object shown in LVF couldn’t say what they saw - could select a matching object out of sight using their hand
• LH is verbal
• RH is silent

Question 7

what are the strengths of hemispheric lateralisation

Answer 7

Gereon Fink (1996)
- used PET scans to identify which brain areas were active during a visual processing task
- pps with connected brains locked a global elements of a picture the RH more active and when focused LH dominated

Question 8

what is the limitation of hemispheric lateralisation

Answer 8

• idea that LH is an analyser and RH is a synthesiser may be wrong
• research suggests that people don’t have a dominant side of their brain creating a different personality
• left and right brained people is wrong

Question 9

what is the strength of split brain research

Answer 9

Michael Gazzaniga
- split brain pps perform better than connected controls on some tasks
- faster at identifying the odd object out

Question 10

what is the limitation of split brain research

Answer 10

• casual relationships are hard to establish
• behaviour of pps was compared to a neurotypical control group
• no pps in control group had epilepsy
• any observed differences may be the result of epilepsy not split brain

Question 11

what is the right hemisphere

Answer 11

• recognises emotions in others
• spatial information
• study of a woman with no RH, got lost in familiar places, needs verbal cues