hemispheric lateralisation

Question 1

what is hemispheric lateralisation?

Answer 1

the two halves (hemispheres) of the brain are functionally different and certain mental processes/behaviours are mainly controlled by one hemisphere rather than the other
e.g. language

Question 2

language

Answer 2

language- 2 main centres only in LH for most people
language is lateralised- performed by one hemisphere rather than the other
RH can only produce rudimentary words/phrases but contributes emotional context to what is being said

LH- analyser RH- synthesiser

Question 3

non-lateralised functions

Answer 3

e.g. motor and somatosensory areas appear in both hemispheres

motor area- brain is cross-wired, RH controls movement on left side of body, LH right

vision

Question 4

vision

Answer 4

both contralateral and ipsilateral

each eye receives light from LVF and RVF
LVF of both eyes connected to RH
RVF of both eyes connected to LH

enables visual areas to compare slightly diff perspective from each eye and aids depth perception

Question 5

strength- lateralisation in connected brains

Answer 5

even in connected brains two hemispheres process info differently

Fink- PET scans identified which areas active in visual task, participants connected brains
focus on global elements of image- RH regions more active
finer detail- LH regions more active

strength- HL feature of connected brain as well as split-brain, accurate and generalisable

Question 6

limitation- analyser and synthesiser wrong

Answer 6

LH and RH diff functions
but research shows ppl don’t have dominant side of brain creating diff personality

Nielson- analysed brain scans from over 1000 ppl, used certain hemisphered for certain tasks but no evidence of dominant side

limitation- notion of right/left-brained ppl wrong, elements of theory invalid

Question 7

question- is lateralisation or plasticity more adaptive?

Answer 7

lateralisation- enables 2 tasks to be performed simultaneously w/ greater efficiency
Rogers- lateralised chickens could find food while watching for predators but normal ones couldn’t
adaptive- increases survival

plasticity- following damage some functions can be taken over by non-specialised areas in opposite hem
e.g. language
adaptive- more chance of survival after damage