22 - Language I Flashcards
What are the two main blood vessels that bring blood into the brain?
Internal Carotid (from aorta)
Vertebral Artery (crosses spine and enters brain at back of head)
How do the anterior and posterior blood vessel systems communicate in the brain?
Through the posterior communicating artery that links the internal carotid with basilar artery.
This circle of blood vessels is known as the circle of willis
What are the three cerebrovascular regions of the brain?
Anterior cerebral artery
Posterior cerebral artery
Middle cerebral artery
^ Territories
Describe the anterior cerebral artery territory
Covers predominately the medial part of the brain and sends branches out to prefrontal, medial frontal and medial parietal areas.
Blood vessels tuck over lateral part of the brain, but not a lot of coverage
Describe the posterior cerebral artery territory
The artery branches from the vertebral artery.
Area covers the medial lobe
Strokes here could affect memory, vision, etc., (rare to have strokes here compared to anterior part of brain)
Describe the middle cerebral artery territory
Covers the largest territory and irrigates most of the lateral surface of the brain.
Main blood vessel sits along the sylvian fissure and sends branches out in all directions.
Strokes here tend to lead to language impairments.
Where does the middle cerebral artery territory supply blood to in the brain?
- Temporal lobe
- Anterolateral frontal lobe
- Parietal lobe
- Basal ganglia (caudate and globus pallidus)
- Adjacent white matter.
What is the perisylvian area?
Located in the vascular domain of the medial cerebral artery and contains a number of language-related areas.
Which hemisphere are language areas typically situated in the brain?
Left
How did Broca discover broca’s area?
Through “Tan” patient (Leborgne)
He lost all of his ability to speak,except for syllable “tan”
At autopsy, he had a stroke in the inferior part of the frontal lobe in the left hemisphere.
Concluded this area (Broca’s area) was the speech centre
Where is Broca’s area located in the brain and what does it include?
Inferior frontal gyrus of the left hemisphere.
Includes pars triangularis and pars opercularis
Broddmann areas 44/45
How did Wenicke discover Wenicke’s area?
Reported 2 people with intact hearing but selectively impaired speech comprehension.
Speech fluent, but nonsensical and disorded words.
Proposed two brain areas involved in language, motor area (Broca’s) and sensory containing memory images of past sense impressions (Wenicke)
Where is Wenicke’s area located?
Posterior third o the superior temporal gyrus
Broddman area 41/42 and 22
Describe the classical model of aphasia
Lichteim (1885) then Geshwind (60s)
- Motor language area (Broca’s)
- Sensory language area (Wernicke’s)
- Concepts (semantics) stored in other areas
- Articulate fasciculus connects B and W
Sensory -> Concepts -> Motor AND
Sensory -> Motor
In the clinical model of aphasia impairments occur at each area after damage?
Concepts - semantic impairments, agnosias, etc.
Motor - Broca’s (expressive) aphasia. Impaired production
Sensory - Wenicke’s (receptive) aphasia. Impaired comprehension
Articulate - Conduction aphasia, impaired repetition
Describe the clinical classification of the 5 types of aphasia’s
Broca's - Expressive aphasia Wenicke's - Receptive aphasia Conduction - disorder of repetition Transcortical - can't repeat words they don't comprehend Global - all of the above
What are the uses of the clinical classification of aphasia’s?
For clinical management and localisation of damage.
Not for understanding neural basis of language processing
What are the characteristics of Broca’s aphasia?
Non fluent Difficulties articulating (Apraxia of speech and dysarthria) Anomia (word finding difficult) Absence of function words (the, a, on) Agrammatism (difficult complex grammer) Better comprehension, not perfect.
Often other neurological signs (right sided weakness or hemiparesis, oro-facial apraxia)
What are the characteristics of Wenicke’s aphasia?
Severe anomia (can't recall everyday objects) Fluent and grammatical speech but largely meaningless (paraphasias [phonological approximations] and jargon)
Impaired reading, comprehension and repetition)
What are the characteristics of Conduction aphasia?
Impaired repetition with relatively good spontaneous speech and comprehension
Phonemic paraphasias in spontaneous speech, which get progressively closer to target word.
Thought to be caused by damage to articulate fasciculus. Disconnection between areas involved in word recognition and production
