Neural Circuits of Language And Communication Flashcards
Cognitive Neuroscience def (1)
the study of the neurobiology that underlies (or creates) cognition
Language def (2)
verbal message and some of the paraverbal components.
2 proprieties are common to every language:
* decomposable
* combinable
Communication facts (3)
everything that conveys a message
- 93 % of communication is non verbal.
- Only 7 % of the message is conveyed by language
- irony, mood, emotions … are components that rely on inferential
processes to be detected
Components of L&C (6)
Phonetic
Phonology
Lexicon-Semantic
Morphology
Syntaxis
Pragmatic (Communication)
Phonetic def (1)
Elaborates linguistic sounds based on their physical characteristic
Phonology def (1)
Distinguish phonemes based on their distinctive tracts; it plans the sequential order for a string (i.e. a word)
Lexicon-semantic def (1)
Contains conceptual representations of meanings and the verbal etiquettes associated with them.
Morphology def (1)
Elaborates morphological aspects of words (such as the –s at the end of the words when they’re plurals)
Syntaxis def (1)
Elaborates sequences of words according to the specific rules of a language
Pragmatic communication def (1)
Explicit the use of the language in a context
Classic language model: Speech input/output flowchart (4)
1) semantics/concepts
2a) Wernicke’s -> Auditory cortex - speech output
2b) Broca’s -> motor cortex -> speech output
3) Wernicke’s <-> Broca’s
image
Lateralisation of the brain (3)
- left dominance is established
- bilateral involvement when it comes to learn a new language
- left dominance for proficient bilinguals in both L1 and L2
New models – Hickok & Poeppel
2007 - dorsal + ventral stream (2)
dorsal stream: Speech production (Broca’s)
ventral stream: speech recognition + comprehension (Wernicke’s)
Dual stream model (3)
image
- Dorsal and ventral streams
- spectrotemporal analysis
- Phonological network
etc.
Approximate anatomical correlates (4)
- superior temporal gyrus (STG) = involved in spectrotemporal analysis
- the posterior half of the STS = implicated at phonological-level processes
- the ventral stream is bilaterally organized with a weak left-hemisphere bias. The more posterior regions of the ventral stream, posterior middle and inferior portions of the temporal lobes correspond to the lexical interface, which links phonological and semantic information, whereas the more anterior locations correspond to the proposed combinatorial
- dorsal stream, = strongly left dominant. The posterior region of the dorsal stream corresponds to an area in the Sylvian fissure at the parietotemporal boundary (area Spt), which is proposed to be a sensorimotor interface, whereas the more anterior locations in the frontal lobe, probably involving Broca’s region and a more dorsal premotor site, correspond to portions of the articulatory network
Ventral stream – parallel analysis explained (4)
Parallel routes in the mapping from acoustic input to lexical phonological representations:
acoustic inputs:
- gamma range - faster (both hemispheres)
or
- theta range - slower range (right hemisphere)
these pathways interact - both within + b/w hemispheres!
- yet each appears capable of separately activating lexical phonological networks
Dorsal stream - 2 levels (4)
- Segmental-level processes would be involved in the acquisition and maintenance of basic articulatory phonetic skills
- Auditory–motor processes at the level of sequences of segments would be involved in the acquisition of new vocabulary, and in the online guidance of speech sequences
Integration of the two levels: auditory–motor interactions in the acquisition of new vocabulary involve generating a sensory representation of the new word that codes the sequence of segments or syllables.
= This sensory representation can then be used to guide more simple motor articulatory sequences
Explain the functional imaging evidence for a sensorimotor dorsal stream (3)
Individuals asked to listen to pseudowords and then subvocally reproduce them.
The analyses focused on regions that were active during both the perceptual and motor-related phases of the trial
results: A network of regions was identified, including the posterior STS bilaterally, a left dominant site in the Sylvian fissure at the boundary between the parietal and temporal lobes (area Spt), and left posterior frontal regions
Aphasia def + main distinction (2)
characterised by an impaired language or communication caused by a damage or injury at some level on the neural pathways of L&C – stroke (PSA)
- expressive (speaking) vs receptive(comprehension)
Classification and Features of aphasia (13)
image - flowchart
fluent: produces connected speech + some sentence structure but lacks meaning
–> Language comprehension relatively intact:
—-Conduction aphasia
—-Anomic aphasia
–> Language comprehension impaired
—-Wernicke’s aphasia
—- transcortical sensory aphasia
non-fluent: speech production is poor + effortful, grammar impaired + content words may be preserved
–> Language comprehension relatively intact
—-Broca’s aphasia
—-Transcortical motor aphasia
–> Language comprehension impaired
—-global aphasia
Broca’s aphasia (4)
- lesion in IFG
- Non Fluent
- poor repetition
- comprehension intact
Wernicke’s aphasia (4)
-lesion in STG/STS
-Fluent
- poor repetition
- comprehension impaired
Transcortical motor aphasia (4)
- lesion in white matter dorsal stream
- non-fluent
- good Repetition
- poor spontaneous
Transcortical sensory aphasia (4)
- lesion in white matter ventral stream
- fluent
- Repetition good (echolalia)
- comprehension impaired
Conduction aphasia (3)
- lesion in White matter b/w MTG + IFG
- Repetition is impaired
- Good spontaneous with anomies
Anomic aphasia (2)
- sensorimotor interface lesion
-Many anomies overcome with Passepartout words
global aphasia (2)
- extended lesion (haemorrhagic)
- Production and comprehension are compromised
PPA (primary progressive aphasia) def (1)
it is not an aphasia, it is a subtype of temporal dementia
Crossed aphasia def (1)
occurs when a person demonstrates language impairment after suffering damage to the hemisphere on the dominant side of the body, rather than the alternate side
Subcortical aphasia def (1)
results from damage to subcortical regions of the brain (e.g., thalamus or basal ganglia), and symptoms can mirror those that arise from cortical lesions
What is aphasia severity associated with? (4)
severity is associated with extensive cortical network damage, mostly involving the dorsal stream and, to a lesser extent, the ventral stream
not surprising as the aphasia quotient is heavily weighted for speech production where 3/4 factors that comprise aphasia quotient (speech fluency, speech repetition, and naming) rely on speech production
Even relatively smaller strokes that affect the cortical language network, especially if the affected areas involve links between the dorsal and ventral streams, seem likely to cause aphasia lasting beyond the subacute stage
AQ is sensible to dorsal stream lesions more than ventral stream ones
Time vs Space methods (4)
to investigation reorganisation of language networks most studies use:
- PET scans
- fMRI
= accurately examine spatial components BUT temporal accuracy is low
- EEG
- MEG
= accurately record the electrical activity of the brain at the ms time scale = high temporal resolution
What several ERP components are usually observed in individuals without brain damage in perception/comprehension vs picture naming? (8)
comprehension: P300, N1, N200, N400 _ mismatch negativity (MMN)
picture naming: P100, P200, P300, N1
Mismatched response - MMR (2)
- Neural Activity is typically suppressed in response to expected stimuli and enhanced following novel stimuli
- This phenomenon is known as Mismatched response
Conclusion (3)
1) the same auditory stimuli are processed differentially depending on whether they are perceived as speech or as nonsense electronic whistles
2) the posterior part of the superior temporal sulcus and the supramarginal gyrus are crucial areas for syllable processing but are not involved in the processing of the same physical dimension when the stimuli are not perceived as speech
3) nonphonemic auditory representation and phonemic representation are computed in parallel, but the phonemic network is more efficient and its activation may have an inhibitory effect on the acoustical network. These properties validate the notion of a distinct speech mode in the human brain.
