Biopsychology: Hemispheric lateralisation & Split brain research

Question 1

Hemispheric lateralisation

Answer 1

Refers to idea 2 halves of brain are functionally different

Each hemisphere has functional specialisations

Question 2

Example of functional specialisation for left hemisphere

Answer 2

Dominant in language

Question 3

Example of functional specialisation for right hemisphere

Answer 3

Dominant in visual motor tasks

Question 4

Corpus collosum

Answer 4

bundle of fibres which connect 2 hemispheres

Question 5

Who were the first people to carry out split brain research?

Answer 5

Sperry and Gazzaniga (1967)

Question 6

Split brain patients

Answer 6

Had corpus collosum severed to treat severe epilepsy

Question 7

How does severing the corpus collosum help treat epilepsy?

Answer 7

prevents violent electrical activity that accompanies epileptic seizures from crossing into the other hemisphere

Question 8

What does severing the corpus collosum allow?

Answer 8

Researchers to study the extent to which brain function is lateralised

Question 9

Aim of Sperry and Gazzaniga’s experiment

Answer 9

to examine the extent to which the 2 hemispheres are specialised for certain functions

Question 10

Types of experiments conducted by Sperry and Gazzaniga

Answer 10

Describe hat you see
Drawing task
Tactile test

Question 11

Describe what you see test

Answer 11

Picture presented to right visual field, was processed by left hemisphere
Patient could describe what they saw
Demonstrates superiority of left hemisphere when it comes to speech production

Picture presented to left visual field, processed by right hemisphere
Patient could not describe what they saw - often said nothing was present

Question 12

Drawing task

Answer 12

Picture presented to right visual field, processed by left hemisphere.
Right hand attempted to draw a picture, but never as clear as left hand.
demonstrates superiority of right hemisphere for visual motor tasks.

Picture presented to left hemisphere, processed by right hemisphere.
Left hand (controlled by right hemisphere) consistently drew clearer and better pictures than right hand, even though all pp’s were right-handed.
Demonstrates superiority of right hemisphere when it comes to visual motor tasks.

Question 13

Number of pp’s in Sperry and Gazzaniga’s research

Answer 13

11

Question 14

A03 - strength of split brain research

Answer 14

Clearly shows lateralisation of function

Question 15

A03 - weakness of split brain research

Answer 15

Presence of confounding variables -
although all patients underwent commiserurotomy, may be differences in extent of lesioning off corpus collosum
This would have affected the degree to which the 2 hemispheres could relay information between themselves

Question 16

A03 - Turk (2002)

Answer 16

Patient J.W. developed language ability in his right hemisphere

Question 17

A03- Szaflarski (2006)

Answer 17

Lateralisation changes with age
Language is more lateralised to left hemisphere between childhood and 25
Then lateralisation decreases

Question 18

What operation did epileptic patients undergo?

Answer 18

commissurotomy