hemispheric specialisation

Question 1

What are five methods used to investigate hemispheric specialisation?

Answer 1

Studying effects of disconnecting the hemispheres (split-brain)

Using the divided visual field technique

Deactivating one hemisphere (e.g., Wada test)

Studying effects of damage to one hemisphere

Measuring hemispheric brain activation

Question 2

What is a callosotomy?

Answer 2

A surgical procedure that severs the corpus callosum, disconnecting the two hemispheres (split-brain surgery).

Question 3

What does the divided visual field technique rely on?

Answer 3

The anatomy of the visual pathway:

LVF stimuli → Right visual cortex

RVF stimuli → Left visual cortex

Question 4

What is the Wada test?

Answer 4

A test where sodium amytal is injected into one carotid artery to temporarily deactivate one hemisphere and test function in the other.

Question 5

What does the Wada test reveal about language lateralisation?

Answer 5

Most people have left hemisphere dominance for language

When the left hemisphere is deactivated, patients usually cannot speak

Question 6

What does split-brain research reveal about the right hemisphere’s language abilities?

Answer 6

The right hemisphere cannot produce speech but may retain some comprehension ability.

Question 7

What are aphasias?

Answer 7

Acquired language disorders affecting language production and/or comprehension, without impairing other functions like perception or memory.

Question 8

How did early studies of aphasia suggest hemispheric lateralisation of language?

Answer 8

Brain-damaged patients with language deficits often had damage to the left hemisphere, indicating left-lateralised language function.