hemispheric lateralisation

Question 1

hemispheric lateralisation definition

Answer 1

the idea that the two hemispheres of the brain are functionally different and that certain metal processes and behaviours are mainly controlled by one hemisphere rather than the other, as in the example of language (which is localised as well as lateralised)

Question 2

what is localisation

Answer 2

the fact that some functions, such as visons and language are governed by very specific areas of the brain

Question 3

what is lateralisation

Answer 3

the 2 sides of the brain are called hemispheres

Question 4

what happens for some functions

Answer 4

the localised areas appear in both hemispheres

Question 5

example of a function in both hemispheres - vision

Answer 5

visual areas are in the left and right occipital lobe which is located in the LH and RH

Question 6

what are the two main centres for language

Answer 6

-Broca’s area
-Wernicke’s area

Question 7

what side of the brain is language lateralised to

Answer 7

LH

Question 9

where is Broca’s area

Answer 9

left frontal lobe

Question 10

where is Wernicke’s area

Answer 10

left temporal area

Question 11

what is the RH role in language

Answer 11

can only produce rudimentary (basic) words and phrases but contributes emotional context to what is being said

Question 12

what is the role of the LH and RH in language

Answer 12

-LH is the analyser
-RH is the synthesiser

Question 13

functions that are not lateralised

Answer 13

-vison
-motor
-somatosensory areas

Question 14

what does contralateral wiring mean

Answer 14

brain is cross wired

Question 15

how is movement controlled by the hemispheres

Answer 15

RH controls movement of the left side of the body and LH controls movement on the right

Question 16

how is vision controlled by hemispheres

Answer 16

-contralateral and ipsilateral (opposite and same sided)
-each eye receives light from the LVF and RVF
-LVF of both eyes is connected to the RH
-RVF of both eyes is connected to the LH
-allows visual fields to compare slightly different perspective from each eye and aids depth perception

Question 17

what arrangement is auditory input to auditory area and the disparity from the two inputs to help us locate the sounds of the source similar to

Answer 17

vision

Question 18

strength of hemispheric lateralisation - lateralisation in the connected brain

Answer 18

-research showing that even in connected brain the two hemispheres process information differently
-Fink et al 1996 used PET scans to identify which brain areas were active during a visual processing task. when participants with connected brains were asked to attend to a global elements of an image (such as looking at a picture of a whole forest) regions of the RH were much more active. when required to focus in on the finer detail (such an individual trees) the specific areas of the LH tend to dominate –> at least as far as visual processing is concerned, hemispheric lateralisation is a feature of the connected brain as well as the split-brain

Question 19

limitation of hemispheric lateralisation- one brain

Answer 19

-idea that the LH as an analyser and the RH as synthesiser may be incorrect
-there may be different functions in the RH and LH, but research suggests people do not have a dominant side of their brain which creates a different personality. Nielsen et al 2013 analysed brain scans from over 1000 people aged 7 to 29 and did find that people used certain hemispheres for certain tasks (which is evidence for lateralisation). but there was no evidence of a dominant side –> suggests the idea of right or left-brained people is wrong

Question 20

evaluation of hemispheric lateralisation - lateralisation vs plasticity

Answer 20

-Lateralisation is adaptive as it enables two tasks to be performed simultaneously with greater efficient. Rogers et al 2004 showed that lateralised chicken could find food while watching for predators but normal chicken could not
-on the other hand, neural plasticity could also be seen as adaptive. following damage through illness or trauma, some functions can be taken over by non-specialised areas in the opposite hemisphere. for example Holland et al 1996 said the language function can ‘switch sides’