Lateralisation and split-brain research

Question 1

Define the term split-brain research

Answer 1

Research that studies individuals that are subject to surgical separation of the 2 hemispheres of the brain as a result of severing the corpus callosum.

Question 2

Define the term hemispheric lateralisation

Answer 2

Refers to the fact that some mental processes in the brain are mainly specialised to left/ right hemisphere.

Question 3

Give examples of functions specialised in the left hemisphere

Answer 3

Speech, language and logical tasks like math

Question 4

Give examples of functions specialised in the right hemisphere

Answer 4

visual and motor tasks, facial recognition and creative tasks like art

Question 5

What did Paul Broca establish

Answer 5

Damage to specific area of left hemisphere can lead to language deficits, yet damage to same area on right side doesn’t have same result.

Question 6

Explain split-brain research: Sperry and Gazzanigas research

Answer 6

Split- brain patient would fixate on dot in center of a computer screen while info was presented on either the L/R visual field. They would then be asked to respond either by left hand (controlled by R hemisphere) or right hand or verbally (both controlled by L hemisphere) without seeing what hands were doing.

Question 7

Give an example of what happened in the study?

Answer 7

If patient flashed image of Dog on RVF, when asked to respond they’d say it was a dog, yet when a cat flashed on LVF they would respond with saying they saw nothing. Because language center is located left hemisphere, but since they are split brain patients the left and right hemispheres cannot communicate, hence the info of seeing the cat was not received, so they can’t say they saw it.

Question 8

Therefore, split-brain research shows? And what does it not show?

Answer 8

There are a no. of differences between the two hemispheres ie) both are responsible for different functions.

But, it hasn’t shown that brain is organised into detailed regions specific to different tasks, instead it suggests connectivity between the separate regions is just as vital as operation of specific parts.

Question 9

Key evaluation points for HL and SBR

Answer 9

Advantages of hemispheric lateralisation (Rogers)
Lateralisation changes with age (Szaflarski)
Lateralisation and immune system functioning (Tonnensson, Weeks + Morfit)
Limits of SBR (Andrew)
Language may not be restricted to left hemisphere (Gazzaniga)