hemispheric laterlisation and split brain research Flashcards
what is hemispheric lateralisation
certain functions are goverened by one side of the brain
what is special about the motor area of the brain
The RH controls left side of the body movement
The LH controls right side of the body movemnt.
give an example of centres that are laterlised and some that arent
language is laterised in the left side of the brain i.e. brocas and wernickes areas. RH - visual motor tasks
Not laterlised - vison motor and somatosensory areas appear in both sides of brain.
What is special about the visual area
LVF of both eyes is connected to the RH
RVF of both eyes is connected to the LH
What are the 2 hemispheres connected by and allow them to communicate
corpus callosum
both hemispheric laterlistion and split brain research
ao3: EXCEPTIONS to hemispheric laterialisation/ contradicting research evidence
case study of EB - he had a tumour which resulted in his LH being removed. Which resulted in his language skills being lost - loss of brocas and wernicks area. However 2 years after his language skills had recovered and a fmri showed that language area had been taken over by the RH. This contradicts research into laterlisation as language is laterlised to the LH.
counterpoint its a case study - unable to generalise as there may be individiual differences - functional recovery is more efficent in young people. EB may be considered an abnormal individual.
a03:research evidence
researchers used pet scans to identify active parts in the brain. When participants were given a image and told to focus on the finer details the LH was more active, whereas when told to focus on global elemenets (picture as a whole) RH was more active. Therefore visual processing is lateralised for normal brai and split brain.
ao3: lateralisation changes with age
Szaflarki et al. (2006) found that language became more lateralised to the left
hemisphere with increasing age in children and adolescents, but after the age
of 25, lateralisation decreased with each decade of life. This raises questions
about lateralisation, such as whether everyone has one hemisphere that is
dominant over the other and whether this dominance changes with age.
ao3: generlisation issues of split brain research
ppts in research had epilispy but control group didnt have epilipsy. - Is a confounding variable. Any results that occured may be due to epilispy rather than split brain.
lack of internal validity.
describe split brain research by SPerry
looked at normal brain and split brain ppts ( corpus callosum is removed/cut/severed) - see how certain functions are laterlised.
VISUAL TASK: Image was presneted to their LVF/RVF. When presented to RVF , ppts could verbally descriibe what they see but couldnt when in their LVF.
TACTILE TASK: Object was placed in the R/L hand. when placed on rH, ppts could verbally describe what they feel but couldnt when item in LH.
Sugguests how certain functions are laterlised - language to LH whereas visual motor tasks e.g. drawing to rightH.
