18 - Cortical Asymmetry

Question 1

What is a suclus and gyrus?

Answer 1

Suclus is a groove in the brain and gyrus is a round ridge

Question 2

What is the function of Broca’s area?

Answer 2

Speech production

Question 3

Where is Broca’s area located?

Answer 3

Left frontal lobe,above the lateral suclus

Question 4

Which Brodmann areas is Broca’s area?

Answer 4

44 and 45

Question 5

Where is the primary motor cortex located?

Answer 5

Precentral gyrus (Brodmann area 4)

Question 6

How does brodmann distinguish between different parts of the brain?

Answer 6

Differences in neuron type and density (50 different areas)

Question 7

What is the association cortex?

Answer 7

Areas of the cortex where the function is obscure

Question 8

Which hemisphere controls language?

Answer 8

Left hemisphere

Question 9

What is the Insula?

Answer 9

A hidden region in the left cortex (inside the lateral suclus) which is active during speech production

Question 10

Which side is the opercular cortex thicker on? What is it’s function?

Answer 10

Opercular cortex is thicker on the left side
It’s situated on the upper and lower lips of the lateral fissure
Function - language production

Question 11

What is the function of Wernicke’s area?

Answer 11

Language perception

Question 12

Where is Wernicke’s area located?

Answer 12

Proximal end of the superior temporal gyrus in the temporal lobe

Question 13

What is the difference between expressive and receptive aphasia?

Answer 13

Expressive aphasia - Damage to Broca’s area - Can understand, repetitive, cannot form coherent sentences, sense behind words, disordered grammar, syntax and word order
Receptive aphasia - Damage to Wernicke’s area - Fluent speech, good syntax and no repetition however the content is meaningless

Question 14

What is the name of the fibres which connect Broca and Wernicke’s areas?

Answer 14

Arcuate fasciculus

Question 15

What is Conduction aphasia?

Answer 15

Damage to the arcuate fasciculus, patients show difficulty reading aloud, impaired ability to repeat back words and has word-finding difficulties

Question 16

What are the 5 steps of the Wernicke-Geschwind model?

Answer 16

1 - Primary auditory cortex
2 - Speech perception - Wernick’s 
3 -  Connection - Arcuate fasciculus
4 - Speech production - Broca’s 
5 - Motor cortex

Question 17

What is the artery that supplies blood to Broca and Wernicke’s areas?

Answer 17

Middle Cerebral artery (From the Internal carotid artery)

Question 18

What is global aphasia?

Answer 18

A stroke to the proximal part of the middle cerebral artery affecting both broca and wernicke’s areas

Question 19

How do you test differences in function between the left and right hemispheres?

Answer 19

Before MRI they used the WADA test whereby anaesthetic was injected into the carotid artery on one side

Question 20

What does the right hemisphere corresponding to Broca’s and Wernicke’s areas do?

Answer 20

Non-semantic speech recognition, recognising and producing intonation, rhythm and emphasis

Question 21

What is aprosodia?

Answer 21

Lesion of the right hemisphere regions which correspond to broca’s area causing robotic, monotonous speech

Question 22

Which area of the brain enables you to focus your attention and blocks out distracting inputs? Why is this clinically significant?

Answer 22

Left frontal lobes

Question 23

Which area of the brain maintains broad overall vigilance?

Answer 23

Right frontal lobes

Question 24

What brodmann areas are the posterior parietal cortices?

Answer 24

5 and 7

Question 25

What is associative agnosia?

Answer 25

Damage to the left posterior parietal cortex, leading to a deficit in naming objects

Question 26

What is apperceptive agnosia?

Answer 26

Damage to the right posterior parietal cortex, leading to a deficit in recognising objects in unusual orientations