Split-Brain Research Flashcards
(7 cards)
1
Q
Hemispheric Lateralisation
A
- Language is subject to hemispheric lateralisation (controlled by left hemisphere)
- Specialised areas associated with language are found in one of the brain’s hemispheres, not both
- Broca = left frontal lobe, Wernicke = left temporal lobe
- Right hemisphere (RH) gives emotional context to speech and acts as a synthesiser, while the left hemisphere (LH) acts as an analyser
- Many functions are not lateralised – vision, motor, somatosensory areas appear in both hemispheres
2
Q
Contralateral Wiring
A
- RH controls movement on left-side of body, whilst LH controls movement on the right side
- Vision is both contralateral and ipsilateral (opposite and same sided), with each eye receives info from left visual field (LVF) and right visual field (RVF)
- The LVF of both eyes is connected to the RH, and RVF of both eyes is connected to the LH
- Helps to add depth perception and perspective
3
Q
Split-Brain Info
A
- In normal brain person, the corpus callosum would share the info between both hemispheres giving a complete picture of the visual word
- In split-brain patient, info could not be conveyed from one hemisphere to the other anymore; each hemisphere is now treated as a separate brain – they aren’t communicating
4
Q
Aim Of Sperry & Gazzaniga (1967)
A
- To examine the extent to which the 2 hemispheres are specialised for certain functions
5
Q
Procedure For Sperry & Gazzaniga (1967)
A
- Image/word would be projected to patient’s RVF and the same/different image would be projected to the LVF
- In order to isolate a visual field, Sperry blindfolded one of the participant’s eyes – participants were asked to stare at a designated spot on a screen
- In the describe what you see task, a picture was presented to either visual field, and the participant had to simply describe what they saw
- In the tactile test, an object was placed in one of the patients hands, and they had to describe what they felt OR select a similar object from a series of alternate objects
- At the speed of 1/10th of a second, an image was flashed up in one of the hemispheres – a speed so quick the eyes have no chance of moving, thus the image only gets presented to one hemisphere as it’s only presented in one visual field
6
Q
Key Findings For See Task
A
- When a picture was shown to the right field, the patient could describe what was seen
- If the same object was shown to the left field, the patient could not describe what was seen (said nothing was there)
- The patient could describe the object when it was presented in the right field but not the left because in the normal brain, messages from the RH are relayed to the language centre in the LH, but this isn’t possible in split-brain
7
Q
Key Findings For Tactile Test
A
- When an object was presented to their LVF, they couldn’t attach verbal labels but they could select objects from a bag using their left hand (motor movement = RH)
- This is because objects were behind a screen so as not to be seen
