hem lateralisation and split brain research Flashcards
what can the RH produce
-rudimentary words and phrases but contributes emotional context
what is the role of LH and RH
-LH = analyser
-RH= synthesiser
how do we know some functions are not lateralised
-vision, motor , somatosensory areas appear in both hemispheres
what is the case of the motor area
-it’s cross wired
-RH controls left side
-LH controls movement on the right
what is the case of the vision
- it’s contralateral and ipsilateral
- each eye receives light from LVF and RVF
-LVF of both eyes is connected to the RH and the RVF of both eyes is connected to LH
what does the visual area allow for
-compares the slightly different perspective from each eye and aids depth perception
-similar to auditory (disparity from two inputs helps us locate source of sounds)
what is the split brain research
A procedure severing connections between the brain’s hemispheres, mainly the corpus callosum, helps reduce epilepsy by preventing excessive electrical activity from spreading between hemispheres. This also allows researchers to study each hemisphere’s function independently when communication between them is blocked.
what is the procedure of sperrys research
Eleven split-brain patients were studied using a special setup where images were projected to either the right visual field (LH) or left visual field (RH). Normally, the corpus callosum would share this information for a complete picture, but in split-brain patients, the images could not be transferred between hemispheres.
what were the findings of sperrys research
When a picture was shown to (RVF), split-brain patients could describe it, but not when shown to the (LVF). While they couldn’t verbally label images in the LVF, they could select a matching object with their left hand (controlled by the RH) or choose an associated object. They also showed emotional reactions, like giggling, to images in the LVF but reported seeing nothing or just a flash of light.
what were the conclusion of sperrys research
-certain functions are lateralised in the brain and support the view that LH is verbal and RH is silent but emotional
strength for hemispheric lat?
(lateralisation in the connected brain)
-fink et al used PET scans to identify which brain areas were active visual processing task
-when they looked at global elements e.g a whole forest regions of the RH were active
-when focusing on finer details the specific areas of LH were more dominate
-so hemispheric lateralisation is also in split brain and connected brain
weaknesses for hemispheric lat?
(one brain)
-LH as analyser and RH as synthesiser may be wrong
-recent research suggests people do not have a dominant side of their brain that creates diff personalities
-Nielsen et al analysed certain hems for certain tasks but there was no evidence of a dominant side
strenghs for split brain research?
(research support)
-gazzingna showed split brain participants perform better than connected controls on certain tasks
-faster at identifying odd one out in similar objects than normal controls
-sperrys earlier findings find the left brain and right brain are distinct
weaknesses of split brain research?
(generalisation issues)
-casual rs hard to establish
behaviour of those in sherry split brain Ps compared to neurotypical control grp
-no participant in the control grp had epilepsy
-major confounding variable
- any differences may have been due to epilepsy rather than split brain
(ethics)
-trauama of operation means Ps wouldn’t fully understand implications of what they agreed too
repeated testing overtime may have been stressful
