Neuroanatomy of Language Flashcards
Relevant to SLT
Broca’s area is associated with what area of the brain?
What Broadman’s area ?
And what is it’s primary function?
left inferior frontal gyrus
BA 44, 45, 47
Function: Language Output
Wernicke’s area is associated with what area of the brain?
What Broadman’s area?
What is the primary function?
left posterior temporal cortex
BA 22
Function: Language Comprehension
In the classic aphasia syndromes, describe Broca’s aphasia?
Disturbance of spoken output non-fluent effortful, agrammatic speech unable to repeat words written language affected involving the inferior frontal gyrus but extending beyond this
In the classic aphasia syndromes, describe Wernicke’s aphasia?
disturbance of language input
fluent but disorganisaed speech
paraphasias (phonological and semantic)
unable to repeat
in the classic aphasia syndromes , describe global aphasia?
Severe form of aphasia affecting both expressive and receptive language. Usually associated with large lesions
What is Conduction aphasia?
specific inability to repeat words
What is transcortical motor aphasia?
Broca’s with repetition
What is transcortical sensory aphasia?
Wernicke’s with repetition
What contribution did Dejerine make to neuroanatomy of language?
he identified the angular gyrus as important for reading
What contribution did Geschwind make to the neuroanatomy of language?
he identified the important of white matter connections between language regions
Which side of the brain is language dominant in the majority of people?
The left hemi
How could you test for language dominance?
Using the WADA test - i.e. by injecting sodium amytal into one carotid artery. This anaesthetises one cerebral hemi. By asking specific questions about recognition and remembrance of an object in comparison to naming you can uncover which is the dominant hemisphere
What methods are used to examine the neuroanatomy of language from the 20th century onward?
Cortical Stimulation
fMRI
how does cortical stimulation work?
By either recording electrodes or by stimulating specific electrodes to see what happens. Usually done during surgery (and specifically epilepsy surgery)
What are the main benefits of fMRI for the neuroanatomy of language?
It doesn’t rely on lesions
it gives much more detail
How does fMRI work?
By looking at blood flow into specific regions of cortex
What did fMRI tell us about language comprehension?
That the left was involved in phonological and linguistic information (i.e. meaning)
and the right was involved in intonation, pitch etc.
Overall at speech in complex and requires both hemispheres of the brain to fully interpret
What parts of the brain are activated in phonological processing?
Responding to speech sounds = anterior and posterior superior temporal cortex
Articulatory coding = premotor cortex and posterior IFG
Attention = supramarginal gyrus
What parts of the brain are involved in speech comprehension?
Semantic processing = anterior superior temporal sulcus, bilateral temporal poles, middle temporal gyrus within/adjacent to Wernicke’s area, and the angular gyrus
No syntactic centre
Semantic features = ventral IFG
What areas of the brain are involved in word retrieval?
left prefrontal, posterior temporal and inferior temporal regions
What areas of the brain are involved in speech production?
propositional speech = prefrontal cortex and IFG
articulation = premotor and primary motor cortex
semantics = temporal pole and posterior temporal/inferior parietal regions
repetition = posterior superior temporal cortex that is part of the dorsal auditory pathway
What areas of the brain are involved in reading?
occipital and posterior temporal cortex
early processing is bilateral, visual word recognition is left-lateralised
What area of the brain is involved in writing?
Exner’s area (middle frontal gyrus/premotor cortex)
What is alexia and how is it caused?
disturbance of visual word form recognition with normal comprehension and intact auditory input
Caused by damage to left primary visual cortex AND splenuim (part of the corpus callusum)
