Speech and Cortical Asymmetry

Question 1

Which Brodman’s areas does Broca’s area occupy?

Answer 1

Areas 44 and 45

Question 2

Where is Broca’s area located?

Answer 2

Left hemisphere just above the lateral sulcus, it is part of the inferior frontal gyrus in the premotor cortex

Question 3

What is the function of the opercular cortex?

Answer 3

Involved in speech production

Question 4

Where is the opercular cortex located?

Answer 4

Upper and lower ‘lips’ of the lateral fissure and is thicker in the left hemisphere

Question 5

Where is Wernicke’s area located?

Answer 5

Specialised cortical area at the end of the superior temporal gyrus and is adjacent to primary auditory cortex (also on temporal lobe)

Question 6

What is the consequence of damage to Broca’s area?

Answer 6

Expressive aphasia: halting speech, repetitive, disordered grammar, disordered syntax, disordered word order, meaning behind words

Question 7

What is the consequence of damage to Wernicke’s area?

Answer 7

Receptive aphasia: fluent speech, no repetition, good syntax, grammar ok, speech is meaningless and inapproprite words are used

Question 8

How may someone with damage to Broca’s area present?

Answer 8

Use single words and find it difficult to link words together to form grammatical sentences

Question 9

How may someone with damage to Wernicke’s area present?

Answer 9

Speak fluently but in an almost meaningless way

Question 10

What connects Broca’s and Wernicke’s areas?

Answer 10

A bundle of cortico-cortical association fibres known as the arcuate fasciculus.

Question 11

What happens if there is damage to the arcuate fasciculus?

Answer 11

Conduction aphasia results

Question 12

What is conduction aphasia?

Answer 12

When there is no function of either Broca’s or Wernicke’s areas, the individual displays an impaired ability to repeat back heard of written words but has a relatively good comprehension of language. Speech output is characterised by ‘word-finding’ difficulties, where they struggle to find the appropriate word for the situation and they have have difficulty reading aloud

Question 13

When does a stroke cause speech difficulties?

Answer 13

When it affects the left side of the brain, as this affects Broca’s area

Question 14

Describe the Wernicke-Geschwind model of information transmission between Broca’s and Wernicke’s areas

Answer 14

When we hear speech –> sound waves decoded in Wernicke’s area –> perceived words –> surrounding parietal and temporal cortex process the meaning of these words –> word concepts then formed in Wernicke’s –> sent to Broca’s via arcuate fasciculus –> Broca’s are converts the word concepts into grammatical sentences –> sends these to motor cortex –> speech

Question 15

What is the blood supply to Broca’s and Wernicke’s areas?

Answer 15

Branches of middle cerebral artery

Question 16

How could a stroke produce global aphasia?

Answer 16

If the stroke affects the proximal MCA

Question 17

Which hemisphere is seen to have the most language specialisation?

Answer 17

Left hemisphere

Question 18

What do the Broca’s and Wernicke’s corresponding regions in the right hemisphere do?

Answer 18

Seem to be involved in tasks requiring non-semantic speech recognition and generation such as intonation and rhythm

Question 19

What is aprosodia?

Answer 19

Robotic, monotonous speech

Question 20

What is the role of the left frontal lobe?

Answer 20

Deductive reasoning e.g. analysis and follow logic to a conclusion and filtering of distracting inputs

Question 21

What is the role of the right frontal lobe?

Answer 21

Non-verbal communication skills and intuitive reasoning

Question 22

What is associative agnosia?

Answer 22

Where an individual can’t name objects but can describe their shape, colour and size, and this is due to damage of the left inferotemporal cortex

Question 23

What is aperceptive agnosia?

Answer 23

Difficulty recognising objects in unusual orientations or if they’re in shadow, due to damage of the right inferotemporal cortex

Question 24

What occurs in order for us to be able to recognise and name an object?

Answer 24

Information about object –> right parietal and inferotemporal cortices (IDENTIFICATION and SEPARATION FROM BACKGROUND) –> left parietal and inferotemporal cortex (ASSIGN OBJECT A NAME)

Question 25

What is the fusiform gyrus?

Answer 25

Part of the inferotemporal cortex

Question 26

What is prosopagnosia?

Answer 26

Loss of the ability to recognise faces, stemming from damage to L or R fusiform gyri

Question 27

What is the function of the left fusiform gyrus?

Answer 27

Left fusiform gyrus extracts cognitive information such as the individual’s name, from the stimulation of seeing their face

Question 28

What is the function of the right fusiform gyrus?

Answer 28

Extracts the emotion in the face of the individual