Neurobiology of language Flashcards
What are the classical area of the brain associated with speech production?
Broca’s area (left inferior frontal gyrus)
What are the classical area of the brain associated with speech comprehension?
Wernicke’s area (superior temporal region)
What are Broca’s Aphasia?
A language disorder –> broken speech, inability to find words
What are Wernicke’s Aphasia?
Language deficit associated with comprehension impairment
Describe the Wernicke-Geschwind model.
We repeat something we hear: the auditory info arrives in the auditory cortex –> Wernicke’s area (understood as meaningfull words) -(via the acurate fasciculus)-> Broca’s area (converted to speech)
What is Conduction Aphasia?
Impairment of acurate fasiculus –> problems with repetition, but not speech production or comprehension
What is Global Aphasia?
Impairment of Broca’s, Wernicke’s area and acurate fasiculus
Is the Wernicke-Geschwind model still the best model?
No:
- sensory infor can come directly into Broca’s area
- speech can be disturbed outside of those regions
Which other models are there?
Two sets of dorsal pathways: one for speech production and repeating, another for processing complex syntax
Ventral pathways: takes the sound, and extract the meaning
What are Transcortical Motor Aphasia (TMA)?
- A type of non-fluent aphasia
- good repetition
- comprehension are relatively normal
- damage to frontal areas close to Broca’s area
What are Transcortical Sensory Aphasia (TSA)?
- a type of fluent aphasia
- trouble naming things
- good repetition
- impaired comprehension
- deficits in sematic retrieval
- damage to temporal areas close to Wernicke’s area (inferior)
What are Anomia Aphasia?
- difficulity with word finding and naming items
- speech is fluent and grammatically correct
- good comprehension
- often use vague words for or describe things they can’t name
- damage to
What does TMA, TSA and AA have in common?
- All occur with damage to regions close to, but outside of Broca’s or Wernicke’s area
- Repetition remains intact
How many of right-handed people have left hemisphere dominance?
app. 95 %
How many of left-handed people have right hemisphere dominance?
app. 19 %
What function does the right hemisphere primarily contribute to (speech)?
Prosody
What is prosody?
Modulation of pitch, intonation, melody, loudness, cadence, tempo, stress, accent and pauses
Describe the general development of language.
In very young children language is bilateral, and then it is lateralized in adults
Describe the recovery of left hemiphere strokes in adults.
- Acute phase (0-3 weeks): spontaneous recovery is mainly due to successful reperfusion and a decrease in cerebral edema and inflammation
- Sub-acute phase (<6 months): plastic changes in the brain occur along with the restoration of diaschisis
- Chronic phase (>6 months): recovery is mostly therapy related
Is the right hemisphere mediating recovery after left hemisphere stroke?
The general consensus is that the recovery mostly comes from functional activation of perilesional areas or areas in the left hemisphere that also support language functions
Describe the fenotype of a split brian patient.
- can repeat or describe words presented to right visual field
- can describe object manipulate by rigth hand
- if presented to left visual field cannot do the same (right hemisphere), cannot verbally describe
- cannot describe anything to left of their visual fixation point, but can indicate images non-verbally
–> like two independently functional brains
What is Aprosodia?
Loss of affective-prosodic aspects of language following focal right damage
