Language & Language Disorders

Question 1

Inferior frontal gyrus (IFG)

Answer 1

• Broca’s area
• Area 44 and 45
• Production of language

Question 2

Other regions for speech productions

Answer 2

• The anterior Insula (Left)
- Critical for coordination of speech articulation
- Part of the orofacial motor system
• Precental region: Orofacial musculature control
• The Basal ganglia: cognitive control (enhancement and suppression, initiation)
- support selection of appropriate phonological and
articulatory representations of lexical items
• Cerebellum: motor planing and control

Question 3

Pendfield and stimulation

Answer 3

• Stimulating Precentral areas: evokes sounds or vocalisation
• Stimulating area 44: speech arrest
• Noted that electrical stimulation in any of
the core language areas of the brain will
affect speech
• Peri-Sylvian areas

Question 4

Area 45

Answer 4

• Pars Triangularis
• Involved in active retreival of information before it can
be articulated
• Strong connection with auditory, semantics processing
temporal areas
• Strong connections with other frontal areas
→Integration and selective retreival of information

Question 5

Area 44

Answer 5

• Pars Opercularis
• Intermediate between cognitive retreival (area 45) and
motor/articularoty area (area 6)
• Translate the retreived information into action
• Strong connections to the Supramarginal gyrus
(phonological processing)

Question 6

Posterior temporal regions (Wernicke)

Answer 6

• Wernicke: the critical region for auditory
language comprehension
→ the superior temporal gyrus

Question 7

Comprehension of language: Acoustic-phonological analysis of the speech input

Answer 7

• Heschl’s gyrus, Primary auditory cortex (area 41, 42)
→ superior surface of the temporal lobe
→ processing of any type of sound
• Superior temporal gyrus (STG) and sulcus (STS) (area 22), Secondary auditory cortex
→ responds to acoustic features of phonetic parameters
→ differentiate speech versus nonspeech sounds

Question 8

Comprehension of language: Syntactic and semantic processing

Answer 8

MTG: comprehension of words
STG :
• pSTG/STS
-semantics, grammatical aspects
• aSTG
- processing syntactic structure (ex: not activated when just a list of words), but also for semantic processing

Question 9

Sentence processing

Answer 9

1) acoustic-phonological analysis
2) sentence-level processing: local phrase is built on the
basis of word categories
3) syntactic and semantic relations in the sentence =
interpretation and comprehension

Question 10

Connections within the language network

Answer 10

• Short range (e.g.: within the IFG) and long range (e.g.: connecting temporal to frontal language areas)
• Dual stream model
- the ventral pathway:
→support sound-to-meaning mapping,
- the dorsal pathway:
→ support auditory-motor integration

Question 11

Arcuate Fasciculus (AF)

Answer 11

• The classic language pathway
• A large bundle of axons that link the posterior temporal language region with ventrolateral frontal areas arching around the posterior end of the lateral fissure.
• The AF connects the posterior temporal region involved in the comprehension of language (often referred to as Wernicke’s area) with the inferior frontal gyrus (IFG) where Broca’s area lies, i.e. the key region for language production
• Lesions of the fibers of the left AF disconnecting the
posterior temporal language region from the IFG are
considered to result in conduction aphasia
 Impairment in the repetition of speech

Question 12

Two branches of the AF

Answer 12

• Ventral branch: Connecting the IFG
• Dorsal branch: Connecting more dorsal regions of the frontal lobe (ex: area 8), for attentional control
→auditory frontal attention

Question 13

The Superior Longitudinal Fasciculus (SLF)

Answer 13

3 Major branches:
SLF I: links the superior parietal lobule with caudal dorsolateral and dorsomedial frontal regions
SLF II: links the caudal part of the IPL (Angular gyrus) with lateral frontal areas, including area 45
SLF III: links the rostral part of the IPL (Supramarginal gyrus) with lateral frontal areas (including area 6 ventral and 44)

Question 14

SLF III

Answer 14

• Stronger connections to area 44
- precise macaque monkey invasive anatomical studies
- resting-state in humans
• Connections of the Supramarginal gyrus with Broca creates an articulatory loop
• Involved in phonological processing

Question 15

SLF II

Answer 15

• Stronger connections with area 45
• Connections with the Angular gyrus: semantic processing and reading
• Involved in semantic processing and with verbal retrieval.

Question 16

The Temporo-Frontal Extreme Capsule Fasciculus

Answer 16

• Connects the ventrolateral frontal region with the intermediate part of the supero-lateral temporal region: associated with the long-term storage of semantic information
• Runs under the insula
• Ventral stream of language
• Associated with the controlled retrieval and selection among competing semantic representations

Question 17

Dorsal and ventral streams

Answer 17

• Superior temporal and premotor regions, activated during repetition, interact via a dorsal pathway along the AF/SLF.
• Middle and inferior temporal regions and the ventrolateral prefrontal cortex, activated during auditory
comprehension, interact via a ventral pathway that runs through the TFexcF

Question 18

Aphasias

Answer 18

• Disorders of language resulting from brain damage
• Historically, 2 types: language and speech disorders
- Speech: verbal output is impaired, because
articulation muscles are weak or uncoordinated
- Language: verbal output is incorrect linguistically
• Can also observe deficits in comprehension of spoken
or written language (normal hearing and vision)
• Other intellectual abilities are normal

Question 19

Broca’s aphasia

Answer 19

• Expressive aphasia
• Reduced speech production
• Slow speech, effortful, not fluent
• Poor articulation
• Fails to produce correct English sentences
- Only basic words and endings are omitted
- Aggrammation: no grammatical structure, problems with syntax
• Similar deficits when writing
Preserved:
- Single word finding
- Language (spoken and written) comprehension
- Musical capacities
*Sometimes paralysis of the right side of the body

Question 20

Wernicke’s aphasia

Answer 20

• Receptive aphasia
• No paralysis
• Speech output speed unaffected or more rapid than normal
• Effortless speech
• Normal prosody, rhythm, melody of speech
• Speech is empty, conveys little information, neologisms
• Paraphasia
• Profound failure to understand language (spoken or written)
-no vision or hearing impairment
• Lost the semantic meaning of words, i.e. the sound patterns received in the primary auditory area

Question 21

Paraphasia

Answer 21

error in word usage

• phonemic paraphasia: replace a single sound.. Ex: ‘’spoot’’ instead of ‘’spoon’’
• Verbal paraphasia: replace a whole word. Ex: ‘’fork’’ instead of ‘’spoon’’

Question 22

Wernicke’s theory

Answer 22

• Broca’s area
- located in front of motor areas for face,
tongue, lips, vocal cords…
- Contains the rules and code for articulation
• Wernicke’s area
- Located next to the hearing area
- Involved in the recognition of the patterns of
spoken language
• The two areas must be connected

Question 23

Conduction Aphasia

Answer 23

• Fluent paraphasiac speech and writing
• Comprehension intact
• Deficits in sentence repetition
→ disconnection between Wernicke and Broca
→ damage to the Arcuate fasciculus
• But each region is intact (fluent speech and normal comprehension)
• Lesions in the inferior parietal lobe near the supramarginal gyrus
- If you ask them a question they will respond so there is some speech comprehension
- If you ask to repeat a sentence: can do it but not exact and harder with difficult sentences

Question 24

Parietal lesion (around the supramarginal gyrus)

Answer 24

speech is not perfect:
paraphasias, language comprehension problem, concluded that paraphasias (ex : substituting one word for another) is a problem of disconnection

Question 25

Damage to the anterior and intermediate temporal areas

Answer 25

sound-to-meaning problems, difficulties with semantic interpretation of what is being said

Question 26

Julia’s Case

Answer 26

• Can’t name things she sees, but she can describe them, she knows what they are.
• Parietal lobe! → translating visual information into speech

Question 27

Apraxia of speech

Answer 27

• Impairments in the coordination and planning of
speech movements, articulation
• Making articulatory errors
• Intact: ability to perceive speech sounds
• Lesion in the Insula: the left precentral gyrus part

Question 28

Isolation of the speech area

Answer 28

• No language comprehension
• No spontaneous speech production
• Can repeat perfectly
• Can even complete a sentence
→Peri-sylvian language areas are spared
but disconnected from the rest of the brain

Question 29

Lesions in the right hemisphere

Answer 29

Problems :
-prosody, or cadence and intonation of speech, and pragmatics,
-sound flat in their intonation,
-may fail to comprehend emotional nuances, irony, sarcasm, and humor in the speech of others.
→They understand what is said but not how it is said.
• Right hemisphere: music perception

Question 30

Lateralization of language functions

Answer 30

Language: Left hemisphere Bilateral Right hemisphere
Right-handed 96 % 0 % 4 %
Left-handed 70 % 15 % 15 %

Question 31

Dyslexia

Answer 31

• Difficulties in the acquisition of literacy
• Can show some impairments in speech processing on tasks requiring manipulation and memory of speech sounds
• Also some low-level visual processing (ex: fast moving objects)
• Developmental dyslexia can be due to different reason
- less activation in Area 44/6 (articulation) and in ventral occipito-temporal areas

Question 32

Reading acquisition

Answer 32

• When we learn how to read, we transform some of the visual structures into a specialised area for reading
• Temporal lobe: for sentence comprehension, not specialised for reading, also activated when hearing sentences

Question 33

Alexia with Agraphia

Answer 33

• Patient lost the ability to read and write
• Good vision
• No Aphasia
• Lesion: Angular gyrus

Question 34

Pure Alexia without Agraphia

Answer 34

One patient:
• right visual field defect
• lost ability to read
• Can still write but can’t read what he just wrote
Lesion: left visual cortex + posterior portion of the corpus callosum
Dejerine’s explanation: written language can only reach the right hemisphere (and no transfer possible to the left-language comprehension hemisphere)

Question 35

Seeing language

Answer 35

Retina → Striate cortex → Secondary visual areas → Angular gyrus (where visual information is represented in space)

Question 36

Hearing language

Answer 36

Ears → Primary auditory area → Wernicke’s area

Question 37

Lesions of the VWFA

Answer 37

Also causes Pure Alexia
This part of the cortex possesses prior properties making it appropriate for reading
• Preference for high-resolution shapes
• Sensitivity for line configurations (useful for object recognition)
• Location: Proximity and connections to spoken language areas

Question 38

The recycling hypothesis

Answer 38

As you acquire expertise, the VWFA area of the fusiform area becomes more active

Question 39

Dysgraphia

Answer 39

• Developmental dysgraphia
→Impairment in acquisition of writing skills
- Handwriting impairement
- Can also affect spelling

Question 40

Agraphia

Answer 40

Acquired writing impairment : lesion
Two sources:
1) Don’t know or remember how to write the words:
-phonological aspect, orthographic memory
2) Can’t write: motor aspect → apraxic dysgraphia