Hemispheric lateralisation - AO1

Question 1

What is hemispheric lateralisation?

Answer 1

Idea that two halves of the brain are functionally different and that certain processes/behaviours are dominated by one hemisphere rather than the other
E.g language is lateralisaed to the left hemisphere

Question 2

Where is language lateralised to?

Answer 2

• Lateralised (only in right hemisphere)

Question 3

Where is movement contralateral to?

Answer 3

Cross wired
Left hemisphere control the right side

Question 4

How does vision work?

Answer 4

Contralateral and ipsilateral (cross wired and on the same side)
Information from the right visual field is processed by the left hemisphere but the two sides communicate with each other to give a full visual picture

Question 5

What is the corpus callosum?

Answer 5

The two hemispheres of the brain communciate with each other through the corpus callosum
The corpus callosum is a bundle of 300 million nerve fibres (myelinated axons) that connects the two hemispheres

Question 6

What is an example of spilt brain research?

Answer 6

Sperry investigated lateralisation in epilepsy patients after they had to cut the corpus callosum and other tissues connecting the hemisphere
So, their two hemispheres could not communicate with each other, restricting come functioning

Question 7

What did Sperry (1968) investigate?

PPs, procedure

Answer 7

Created a system to determine how specific functions are lateralised across hemisphere
11 split brain patients

• The image/ word briefly projected to the patients left visual hemisphere (processed by the right hemisphere) or right visual hemisphere (processed by left hemisphere)
• When information is presented to one hemisphere in a split brain patient, the info is not transferred to the other hemisphere

Question 8

What did Sperry find about language in split brain patients?

Answer 8

• Words presented in the right visual field could be verbally described
• If images/words presented in the left visual field, patient would say there was nothing there so language is lateralised to the left hemisphere

Question 9

What did Sperry find about visual motor tasks in split brain patients?

Answer 9

• Words presented in the left visual field could still trigger movement from the left hand to draw the word
• Left could select a similar object by touch
  Therefore visual motor tasks are lateralised to the right hemisphere

Question 10

What did Sperry find about emotion?

Answer 10

• Image boards presented in left visual field could trigger an emotional reaction (e.g laughing)
• But PPs could still not verbally describe the image
  Therefore emotions are lateralised to the right hemisphere

Question 11

What is the left hemisphere?

Answer 11

• The analyser
• Language talking and reacting
• Control of right side of body
• Processes info from right visual field
• Arithmetic
• Objectivity

Question 12

What is the right hemisphere?

Answer 12

• The synthesiser
• Visual-motor tasks context
• Controls left side of the body
• Processes info from the left visual field
• Facial recognition
• Emotional context
• Drawing