Split brain research Flashcards
(14 cards)
What is a split brain?
Operation involves severing the connections between the right hemisphere and the left hemisphere
Mainly the corpus collosum
What is this surgical procedure used for?
To reduce epilepsy
What happens when someone has an epileptic seizure?
Brain experiences excessive electrical activity that travels from one hemisphere to another
How does the surgical procedure reduce epileptic fits?
Connections are cut
Splitting the brain into two halves
What is split brain research?
Studies how hemispheres function when they cant communicate with each other
What did Sperry devise?
A system to study how two separated hemispheres deal with for example, speech and vision
What was Sperry’s procedure?
11 people who had split brain operation
Special set up
Image could be projected to a participants right visual field and same/different image could be projected to the left visual field
What would happen in a ‘normal’ brain during this procedure?
The corpus callosum would immediately share information between both hemispheres giving a complete picture of the visual world
What did presenting the image to one hemisphere of the split brain patient mean?
Information cannot be conveyed from that hemisphere to the other
What were Sperry’s findings?
When pic of object show to right visual field (left hemisphere)
Participant could describe what they have seen
But when shown to left visual field (right hemisphere)
Patient could not describe what they have seen - said there was ‘nothing there’
In connected brain, messages from right hemisphere are relayed to the language centres in the left hemisphere but not possible in the split brain
What happened even thought participants couldn’t give verbal labels to objects projected to the left visual field?
Could select matching object out of side using left hand
Left hand was also able to select object that was most closely associated with an object presented to the left visual field.
Eg. ashtray selected in response to a picture of a cigarette
If pinup picture picture shown - left visual filed there was an emotional reaction but participants usually reported seeing nothing or just a flash of light
What were Sperry’s conclusions?
Show how certain functions are lateralised in the brain
Support view that the left hemisphere is verbal and the right hemisphere is ‘silent’ but emotional
What is a limitation of split brain research?
Casual relationships hard to establish
Compared to neurotypical control group
Non of control group had epilepsy
Confounding variable
Any differences may be due to epilepsy not split brain.
Meaning some unique features of split brain participants cognitive abilities might have been due to their epilepsy.
What is a negative of split brain research?
Split brain operation not performed for purpose of the research
Participants not harmed deliberately
All procedures were explained and full informed consent was obtained
Trauma may have meant participants did not fully understand implications of what they had agreed to
Subject to repeated testing over a lengthy period - may have been stressful overtime
