Neuroanatomy of Language Flashcards
Order of primary visual cortex for language processing?
Primary Visual Cortex (BD 17) – receives the message
↓
Visual Association Cortex (BD 18) - Analyze stimuli shape/length
(BD 19) – Recognize seen before
↓
Wernicke’s Area – superior temporal gyrus, posterior portion
↓
Broca’s
↓
Primary Motor Cortex – lateral portion close to Broca’s area
↓
Brainstem
CN VII – lips
CN IX – pharynx & soft palate
CN X – pharynx/vocal folds
CN XI – cranial branch
Cn XII - tongue
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Brainstem
CN VII – lips
CN IX – pharynx & soft palate
CN X – phayrnx/vocal folds
CN XI – cranial branch
Cn XII - tongue
Where is the breakdown for dysarthria?
In information sent to the cranial nerves
Where is the breakdown for receptive aphasia?
Wernicke’s area
Where is the breakdown for expressive aphasia?
Broca’s
Where is the breakdown in conduction aphasia?
Arcuate fasciculus
What is conduction aphasia?
fluent but paraphasia error, repetition severely impaired, naming & writing also impaired, reading aloud impaired,
comprehension intact, reading comprehension preserved
What is the arcuate fasciculus?
Bundle of axons that connect temporal and inferior parietal cortex to frontal lobe
Specifically connecting Broca’s and Wernicke’s areas, crucial for processing and producing language
Latest regions to mature, undergoes a lateralization shift in adolescence
What does damage to the arcuate fasciculus create?
Damage to this area contributes to conduction aphasia, schizophrenia, auditory hallucinations
Connectivity studies arcuate fasciculus concomitate with superior longitudinal fasciculus has complex structures connecting multiple target areas in frontal cortex with multiple target areas in temporal and parietal cortex
What is the left peri-sylvian cortex?
Region around lateral sulcus (Sylvian fissure) includes both Broca’s and Wernicke’s areas
Includes inferior frontal gyrus, premotor cortex, upper temporal lobe and temporoparietal interface
What is missing from wernicke-lichtheim-geschwind?
Does not account for range of aphasia syndromes
Does not allow for hierarchical nature of language
Linguistically underspecified
Anatomically underspecified
What is the dual route model of language?
Cortical Organization of speech processing
Previous theories failed to consider task effects when mapping speech related processing systems
What are the 3 concepts of the dual route model of language?
- Acoustic speech information interfaces with two systems:
- Conceptual & * Motor
- Speech comprehension relies predominantly on conceptual/memory
interface - Speech production is sensory & motor production
What is the dual stream model, and what are the 2 streams?
similar to those seen auditory & visual systems
Ventral stream – processes speech for comprehension, auditory to conceptual
Dorsal Stream - acoustic signals frontal lobe articulatory networks, auditory to motor
What is the dorsal stream?
WHERE
production aka form to phonology to articulation
left hemisphere dominant
sensorimotor
Left Sylvian parietal -temporal
Articulatory network inferior frontal (Broca’s)
lateral pre-motor areas for articulation
What is the ventral stream?
WHAT
comprehension aka form to lexico-semantics to meaning
bilateral
temporal lobe
Posterior middle and inferior temporal gyrus
travel to ant. middle temporal
What are connectomics?
Comprehensively mapping the neural elements and interconnections that constitute the brain
Advances in MRI allowed in vivo assessment (assessment in a living organism)
…research into circuit -level, connectome-wide and topological changes is stimulating the development of new aetiopathological* theories and biomarkers with potential for clinical translation.
What are the 3 basic concepts in connectomics?
- Defining the regions
- Measuring connectivity between these regions
- Network analysis
- determination of the cause of a pathology
If you are right handed, what percentage of language representation is left/right? Bilateral?
Left- 96%, Right 4%, Bilateral 0%
If you are left-handed, what percentage of language representation is left/right?
Left 70%, Right 15%, Bilateral 15%
Which hemisphere is dominant for langauge?
LEFT
About the left hemisphere?
Holds almost exclusively the ability to use syntax and phonology
Is largely organized such that the anterior, dorsal, and motor portions of the brain are important for production
And the posterior, ventral, and temporal lobe portions are important for comprehension
What is the right hemisphere dominant for?
Visual-spatial skills
Pragmatics
Attention
What does the right hemisphere NOT express?
Phonology
Syntax
Morphology
Motor & Articulatory components/Prosody and Tone?
Motor control and motor planning
Dysarthria/Apraxia
Rhythm and tonal patterns
Tasks vs. Process?
Tasks are made up of different processes or subcomponents of language
(Picture naming is a task made up of different processes)
What is categorical perception?
perceive items as belonging to same category, thus more similar to each other and less similar to items form other categories
Speech stimuli intermediate between two phonemes are typically categorized as one or the other, with an abrupt boundary
Some people can still distinguish between two sounds judged to be in the same category
What is selective attention with regard to speech perception?
ability to focus on some inputs while tuning out other
What is the auditory figure ground?
Ability to pick out important sounds within a noisy background
What is segmentation?
Process of identifying boundaries between words, syllables or phonemes in spoken natural language.
What is coarticulation?
production of two or more speech sounds together so that one influences the other.
What is abstraction?
suppose the existence of segments that are more or less different from the surface (i.e. phonetic facts)
What are lexical choices?
choosing the content words (noun, verbs, adjectives, adverbs) in generated sentences.
What is competition among choices?
newly acquired word will engage in competition with existing words that share its onset
Retrieval of Correct choice?
selecting correct word among semantically similar competitors
What is the motor theory of speech for word comprehension?
Infants imitate what they hear and match it motorically
Heavy emphasis of the speakers vocal tract constrictions , each phonetic gesture produced uniquely in vocal tract.
Adults form a motor representation of the spoken message – “embodiment”?
Problem – children understand better than they produce as do people with motor speech impairments
What is the cohort model of speech for word comprehension?
A word is recognized at the point that a particular word can be distinguished from any of the other words in the word cohort set that was defined by the bottom up information in the signal
The critical recognition point of the word
What is the uniqueness point?
the point only one word is consistent with the acoustic signal
What is the TRACE Model?
Works in two directions
Allows either words or phonemes to be derived from a spoken message
By segmenting the individual sounds, phonemes can be determined from spoken words. By combining the phonemes words can be created and perceived
What is a semantic network?
remise is that all ideas in your head are connected together. Activation of one concept can pull up related concepts. People organize their knowledge of the world based on their personal experience.
What is spreading activation?
general elevation and availability of these semantic connections
enhances accessibility to concepts and increases likelihood of retrieval
Syntactic ambiguity types?
Local and global ambiguity
Which type of ambiguity?
“They are cooking apples”
Are apples being cooked or is that the type of apple
global
Which type of ambiguity?
Various interpretations are possible at some point;
Ambiguity is solved by end of the sentence:
Jessica bought blue shirts and shoes that are pink.
local
What is the garden path model?
Sentence structure leads to “wrong” interpretation of the sentence on the first reading.
Only one syntactical structure is considered
One is being led down the garden path…
What is the constraint-based model?
the parser uses all sources of information to constrain meaning (syntactic, semantic )
Sentence processing involves immediate use of all available information to process understand the final outcome.
grammatical knowledge can constrain possible sentence interpretations
