Language in the brain

Question 1

What is language?

Answer 1

intention to communicate
symbol usage
ability to articulate something new
Grammar
ability to represent real world situations

Question 2

What did Rumbaugh (1977) say about language?

Answer 2

“an infinitely open system of communication”

Question 3

What are the two behaviours of language?

Answer 3

Language production - from thoughts to mouth and tongue movement
Language comprehension - from sound waves to thought

Question 4

What are the 2 forms of language?

Answer 4

Auditory (spoken)
Visual (written or signed)

Question 5

What biological systems does language involve?

Answer 5

Auditory system, visual system, motor system, memory

Question 6

What is aphasia?

Answer 6

Disorders of speaking and listening caused by stroke, tumour or head injury

Question 7

What is dementia?

Answer 7

Progressive, degenerative brain disorder which can also affect speech and language

Question 8

What happened to ‘Tan’ (Broca, 1861)?

Answer 8

French hospital patient with lesion that resulted in:
- single syllable speech (“tan”)
- good intonation
- obvious frustration at deficit

Also lost use of right arm & hand

Question 9

What did an autopsy reveal about ‘Tan’ after his death? (Broca, 1861)

Answer 9

A lesion in a region in his left frontal lobe –> Broca’s area

Question 10

What is Broca’s aphasia?

Answer 10

‘expressive’ or ‘production’ aphasia:
slow, deliberate, effortful speech production
non-fluent
omission of grammatical markers
BUT, comprehension is unaffected

Damage to Broca’s area (LEFT hemisphere only)

Question 11

What happened to Wernicke’s (1874) patients?

Answer 11

Case report on 2 patients
- Relatively fluent speech
- Create new words - ‘neologisms’
- Severely impaired comprehension

Question 12

What did Wernicke (1874) find in the post mortems of his 2 patients?

Answer 12

Lesion in a region of the left temporal lobe (Wernicke’s area)

Question 13

What are some of the main differences between Broca’s (non-fluent, expressive) aphasia and Wernicke’s (fluent, receptive) aphasia?

Answer 13

• Those with Broca’s aphasia are generally aware of there deficit while those with Wernicke’s aphasia are generally unaware
• Those with Broca’s aphasia have dysfluent speech production whilst those with Wernicke’s aphasia are fluent but speech is usually content-free (Jargon)
• Those with Broca’s aphasia produce very few function words whereas those with Wernicke’s aphasia often use function words appropriately but content words are often replaced with neologisms
• Those with Broca’s aphasia have agrammatism in comprehension as well as production but are able to comprehend speech whereas those with Wernicke’s aphasia have severe comprehension deficits

Question 14

What are circumlocutions?

Answer 14

Talking around a specific word

Question 15

What are paraphasias (+ examples)?

Answer 15

A language output error associated with aphasia
Phonemic paraphasia, Neologistic paraphasia, Semantic paraphasia, perseverative paraphasia

Question 16

What is phonemic paraphasia?

Answer 16

incorrect phonemes are substituted eg. pike/pipe

Question 17

What is neologistic paraphasia?

Answer 17

the use of non-real words in place of the intended word. eg. Pinwad/light

Question 18

What is semantic paraphasia?

Answer 18

when an entire word is substituted for the intended word. eg. girl/wife

Question 19

What is perseverative paraphasia?

Answer 19

previous responses persist and interfere with retrieval/production

Question 20

What is the Wernicke-Geschwind model (Geschwind, 1972) based on?

Answer 20

Neurobiological bases of language based on studies of brain impairment

Question 21

What is the ‘heard word’ pathway of the Wernicke-Geschwind model?

Answer 21

Heard word –> Auditory cortex –> Wernicke’s area (decodes sounds for meaning) –> Broca’s area (activates speech plan; grammar) –> motor cortex –> speech

Question 22

What is the ‘seen word’ pathway of the Wernicke-Geschwind model?

Answer 22

Seen word –> Visual cortex –> Angular gyrus –> Wernicke’s area (decodes sounds for meaning) –> Broca’s area (activates speech plan; grammar) –> motor cortex –> speech

Question 23

What is the arcuate fasciculus?

Answer 23

a bundle of axons that connects the temporal cortex and inferior parietal cortex to locations in the frontal lobe. One of the key roles of the arcuate fasciculus is connecting Broca’s and Wernicke’s areas

Question 24

What is conduction aphasia?

Answer 24

Fluent speech (relatively spared Broca’s area)
Good comprehension (relatively spared Wernicke’s area)
BUT Inability to repeat spoken language

Question 25

What causes conduction aphasia?

Answer 25

Lesion to arcuate fasciculus - disrupts transfer from WA to BA = difficulty in repeating words but spoken comprehension and ability to speak spontaneously may be OK

Question 26

What happens to language when there is a lesion to angular gyrus?

Answer 26

disrupts flow from visual cortex = difficulty saying words seen but not words heard (word blindness)

Question 27

What is word deafness and what causes it?

Answer 27

Inability to understand spoken words Lesions of fibre tracts from primary auditory cortex to posterior temporal regions

Question 28

What is global aphasia?

Answer 28

- The most severe form of aphasia - Can produce few recognizable words (if any) and understand little or no spoken language - Verbal stereotypy – repeat a sound/phrase over and over in an attempt to communicate - Can no longer read or write - Preserved intellectual and cognitive capabilities unrelated to language and speech

Question 29

What causes global aphasia?

Answer 29

A result of damage to the left perisylvian cortex  Often seen straight after stroke/trauma and can improve If damage is extensive, may be permanent

Question 30

What is apraxia of speech?

Answer 30

- Difficulty initiating and executing voluntary movement patterns necessary to produce speech despite normal muscle strength.   - Slowed speech, abnormal prosody, distortions of speech sounds - Specific neural basis unclear BUT comprehension is fine

Question 31

What is dysarthia?

Answer 31

Difficult or unclear articulation of speech BUT comprehension is fine

Question 32

What causes dysarthia?

Answer 32

- Disruption of muscular control due to lesions of either the central or peripheral nervous systems - Messages controlling the motor movements for speech is interrupted

Question 33

What hemisphere is predominantly responsible for language and what is this suggested by?

Answer 33

Left hemisphere - strongest activation

Question 34

What is lateralisation?

Answer 34

The tendency for a given psychological function to be served by one hemisphere, with the other hemisphere either incapable or less capable of performing the function

Question 35

In what way does the planum temporale demonstrate brain asymmetry?

Answer 35

Larger on the left in approx 65% of people - also evident in newborns

Question 36

What is the right ear advantage?

Answer 36

The right ear projects to the left hemisphere which is responsible for language therefore if 2 different syllables are presented to the right and left ear at the same time, a participant would only repeat the right-ear syllable

Question 37

What is the right visual field advantage?

Answer 37

According to Ellis (2004) the RVF read on average quicker and more accurately

Question 38

What is the Wada technique? (Wada & Rasmussen, 1960)

Answer 38

Inject fast-acting anaesthetic (sodium amytal) into carotid artery supplying blood to left hemisphere. Anaesthesia of left hemisphere and consequent immobility in contra-lateral (right) limbs and speech disruption

Question 39

How does handedness affect hemisphere dominance?

Answer 39

Most people, regardless of handedness, are LH dominant for language BUT When RH dominance occurs, it’s more common in left handed people backed up by fMRI data - LH dominant for speech production in >95% of right-handers vs ~ 80% of left-handers (McKeever et al., 1995).

Question 40

What did Sperry (1969) find in their split brain study?

Answer 40

Present object / word in left visual field --> R.Hemisphere --> can’t name object Present object / word in right visual field --> L.Hemisphere --> can name object

Question 41

When can the right hemisphere take over in language?

Answer 41

Although language is associated with the left hemisphere, in some cases of early damage the right hemisphere can ‘take over’

Question 42

What did Smith and Sugar (1975) find in their case study of a 5 1/2 year old boy who had a left hemispherectomy to treat epilepsy?

Answer 42

at 26: typical language typical verbal and non-verbal reasoning a successful business executive studying part-time for a sociology degree

Question 43

What are the roles of the right hemisphere in language?

Answer 43

- prosody (intonation, emphasis and rhythm) - pragmatic language skills (using language appropriately) - Understanding info from language that is not communicated by word meaning eg. sarcasm

Question 44

What is the left hemisphere responsible for?

Answer 44

controls right sided movement Gets touch information from right side Auditory information (mainly) from right ear Visual information from right visual field (not right eye) Speech (Broca’s aphasia)

Question 45

What is the right hemisphere responsible for?

Answer 45

Controls left sided movement Gets touch information from left side Auditory information (mainly) from left ear Visual information from left visual field (not left eye) Subtle language (e.g., intonation, metaphor comprehension) Visuo-spatial attention