What is the biological basis for language in the brain including audition, action and motor control, cognitive control, and visual object recognition? (5 points)
Language = left-lateralised to regions around Sylvian fissure
1. Audition: posterior, superior temporal love
2. Action and motor control: inferior frontal and parietal
3. Planning, cognitive control: frontal
4. Visual object recognition: inferior temporal
How is language processed in terms of the WLG model? (2 points)
Certain areas of the brain communicate with each other
Extract info about meanings of words
Meanings passed to production and motor areas of brain
What are the biological components of the WLG model? (4 points)
Neural loop runs round lateral sulcus
Broca’s area at frontal end is associated with language production
Wernicke’s area (temporal lobe) associated with language comprehension
Connected by large bundle of nerve fibres: arcuate fasciculus
What does damage to the Broca’s and Wernicke’s area effect in terms of language processing? (2 points)
Broca’s area - impairs phonology and grammar planning
Wernicke’s area - semantic impairments
What is aphasia and what does it affect? (2 points)
Language impairment due to brain damage
Affects language but not intellect
What are three types of aphasia and the three areas impacted/not impacted in each (aka symptoms)?
Broca’s
- Comprehension Intact
- Production non-fluent
- Repetition impaired
Wernicke’s
- Comprehension Impaired
- Production Fluent
- Repetition impaired
Conduction
- Comprehension Intact
- Production Fluent
- Repetition impaired
What are 4 effects of Broca’s aphasia?
- Impaired production
- Dysprosody - trouble with prosodic features of language (intonation, pauses, stress, vocal quality)
- Simplified speech - lexical morphemes e.g. only using nouns, verbs, grammatical constructions simplified
- Agrammatic speech
What are 5 effects of Wernicke’s aphasia?
- Impaired comprehension and repetition
- Paraphasia: wrong combo of words and morphemes
- Neologisms: making up new words
- Produces very fluent speech but usually nonsense + excessive and empty
- Normally suffer insomnia
How does Geschwind model explain how different aphasia are associated with different patterns of word repetition? (auditory cortex, Wernicke’s, Broca’s, motor cortex and primary visual cortex)
- Auditory cortex processes spoken input
- Wernicke’s area processes word meaning
- Broca’s area encodes phonological info (representations for articulating words)
- Motor cortex - make right sounds
- Primary visual cortex - processes written word input
What are 4 effects of conduction aphasia?
- damage to arcuate fasiculus
- selective deficit in word repetition
- reproduction conduction - poor phonological encoding causes impairments in all language product tasks
- short term memory conduction aphasia due to impairment in auditory short term memory
What is anomia? (3 points)
- word finding difficulty
- non focal (not from obvious damage)
- can be seen in all types of aphasia + general disorders of the brain
What are lexical-semantic anomia and phonological anomia? (1 point each)
Lexical-semantic anomia – inability to use semantic representation to select the correct lemma
Phonological anomia – intact semantic information difficulty with the phonological retrieval
What is the difference between heuristic and algorithmic processing in comprehension? (1 sentence each)
Heuristic - based on semantic info, real world knowledge
Algorithmic - based on syntactic info, requires correct syntactic analysis
How does aphasia affect sentence comprehension? (3 points)
- Broca’s aphasia - dissociation between competence and performance
- Competence retained but performance affected
- Trouble with metalinguistic tasks (thinking about language such as asking how words go together)
Can Wernicke’s and Broca’s aphasics use algorithmic procedures in language comprehension? (1 sentence each)
Wernicke’s - comprehension deficit in semantics more affected than sequence-based
Broca’s - intact comprehension but abnormal behaviour in metalinguistic tasks involving grammatical structure
What is wrong with the Wernicke-Geschwind mode ‘Broca-expression’ & ‘Wernicke-reception’? (4 points)
- oversimplifcation
- visual and auditory perceptions of words go via modality-specific pathways
- language processed in both left and right hemispheres e.g. prosody
- cortical and subcortical regions involved in language function
What is the lesion approach and what is its drawbacks? (4 points)
- common areas of injury
- compare behaviour with control group
- loses info when multiple regions contribute to behaviour
- ignores regions outside area of interest
What is the behaviour approach and what is its drawbacks? (4 points)
- group based on language behaviour
- examine lesion overlap
- ignores fact that symptoms often continuous not binary
- can’t capture varying degrees of performance
How has neuroimaging moved beyond the WLD model? What are its benefits?
- more accurate localisation of brain function – - real time processing
- how different areas of brain are involved during a task
- can see if there is overlap in brain function for different tasks
- most inferences about brain structure and specific functions are from fMRI (functional magnetic resonance imaging)
- can artificially recreate brain lesions with techniques such as TMS - temporarily induce language deficits
What is Voxel-based Lesion-Symptom Mapping Bates et al. Nature Neuroscience (2003)? (2 points)
- avoids losing detailed spatial or linguistic information
- per voxel, divide patients into groups that have or do not have a lesion affecting that voxel, and test whether the groups differ in behavioural scores (t-score).
What are the benefits and limitations of Voxel-based Lesion-Symptom Mapping Bates et al. Nature Neuroscience (2003)?
Consistent with historical findings:
- fluency most affected by anterior lesion
- auditory comprehension by posterior lesion
Greatest effect in anterior insula and middle temporal gyrus
Lesion araea may emerge because of direct causal role or because of highly correlated lesions some distance away
How do the affects of the anterior lesion on fluecy and the posterior lesion on auditory comprehension impact the view of the Broca’s and Wernicke’s area? (5 points)
Role of the insula in fluency could be indirect consequence of lesions to Broca’s area
Role of middle temporal gyrus in comprehension could be consequence of lesions to Wernicke’s area.
Can factor out activity from other areas to gain a ‘pure’ measure of lesion
Broca’s area not especially important for fluency after insula lesions factored out
Wernicke’s area not important for auditory comprehension after middle temporal gyrus factored out
What is the relationship between Aphasia and bilingualism?
If bilingual languages with shared neural representation = aphasic symptoms across languages
If neural representation is separate = each language may show different level of impairment and restoration
How does bilingual aphasia show complex patterns? (6 points)
Sometimes asymmetric symptoms, either L1 or L2 is affected
Sometimes shared deficits across L1 & L2
Cannot predict recovery on basis of:
lesion type/site
context or frequency of use
type of aphasia
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Doing Psychology 1.112
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Doing Psychology 1.231
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Doing Psychology 1.312
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Differential 2.1 and 2.211
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Differential 2.39
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Differential 3.19
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Differential 3.2 and 3.325
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Developmental 4.139
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Developmental 4.224
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Developmental 4.330
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Developmental 5.129
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Developmental 5.220
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Developmental 5.336
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Doing Psychology 7.112
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Doing Psychology 7.217
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Language 8.116
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Language 8.211
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Language 8.315
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Language 9.138
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Language 9.231
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Language 9.310
