ARTICULATORY NET I.3 & IIOCT 19, 2015 – DAY 22

Brain & Language

LING 4110-4890-5110-7960

NSCI 4110-4891-6110

Fall 2015

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Course organization• http://www.tulane.edu/~howard/BrLg/• Fun with https://www.facebook.com/BrLg15/• I am still working on grading.• http://www.tulane.edu/~howard/BrLg/t13-IFG.html• http://www.tulane.edu/~howard/BrLg/t14-PMM1.html

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ARTICULATORY NET I.1Review

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The articulator network

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My second revision

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They live in prefrontal cortex

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Executive functions• Executive functions (also known as cognitive control and

supervisory attentional system) is an umbrella term for the management (or regulation, or control) of cognitive processes, including:• working memory• reasoning • task flexibility• problem solving• planning• execution

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Broca's region

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Articulatory Net Hypothesis

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pIFG (BA44)

beaker [bikɹ]

baker [beɪkɹ]

backer [bækɹ]

booker [bʊkɹ]

vPM (BA6)

[beɪk]…

M1 (BA4)

[b … ]

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Response selection or inhibition: Go/no-go task

• A task in which stimuli are presented in a continuous stream and participants perform a binary decision on each stimulus.

• One of the outcomes requires participants to make a motor response (go), whereas the other requires participants to withhold a response (no-go).

• Accuracy and reaction time are measured for each event. Go events typically occur with higher frequency than no-go events.

• http://cognitivefun.net/test/17

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Function segregation in the left inferior frontal gyrus: a listening fMRI study• Four kinds of sounds were used as stimuli: Japanese word,

Japanese nonsense word, English word, and English nonsense word.

• We found a similar function segregation trend in the left inferior frontal gyrus to that found in studies using visual tasks

• The more extensive activation of the dorsal left inferior frontal gyrus in response to the English word and nonsense word listening tasks vs. the Japanese word and nonsense word listening tasks might be related to greater demand for articulatory processing,

• whereas the increased activation of the ventral left inferior frontal gyrus in response to the word listening tasks compared with the nonsense word listening tasks might be related to lexical or semantic processing.

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Visualization of results

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VENTRAL PREMOTOR CORTEXvBA6

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Ventral premotor cortex• The ventral premotor cortex has been implicated in motor

vocabularies in both speech and manual gestures. • A mental syllabary — a repository of gestural scores for

the most highly used syllables in a language — has been linked to the ventral premotor cortex in a large-scale meta-analysis of functional imaging studies.

• A recent prospective fMRI study that was designed to distinguish phonemic and syllable representations in motor codes provided further evidence for this view by demonstrating adaptation effects in the ventral premotor cortex to repeating syllables.

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Apraxia• Greek ‘unable to do’• Difficulty carrying out volitional movement in the absence of sensory loss or paralysis sufficient to explain the difficulty

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Types of apraxia• Ideomotor (inability to carry out a motor command, for example, "act

as if you are brushing your teeth" or "salute")• Ideational (inability to create a plan for or idea of a specific

movement, for example, "pick up this pen and write down your name"),

• Verbal/Apraxia of speech (difficulty planning the movements necessary for speech)• Acquired apraxia of speech occurs most commonly in adults who have already

developed language skills. It is referred to as dyspraxia in less severe cases.• Developmental or childhood apraxia of speech is a congenital (present at birth)

disorder.

• Limb-kinetic (inability to make fine, precise movements with a limb)• Constructional (inability to draw or construct simple configurations),• Oculomotor (difficulty moving the eye)

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YouTube• Ideational apraxia

• Callosal apraxia, ideational apraxia

• Apraxia of speech• 4 1/2 yr old with apraxia talking

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Apraxia of speechaka verbal apraxia or dyspraxia

• Neurogenic phonologic disorder resulting from sensorimotor impairment to the capacity to select, program, and/or execute in coordinated and normally timed sequences, the positioning of speech musculature for the volitional production of speech sounds

• Prosodic alteration, that is, changes in speech stress, intonation, and/or rhythm, (dysprosody) may be associated with the articulatory disruption either as a primary part of the condition or in compensation for it.

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More informally• A patient with apraxia of speech know what words he or she wants to say, but has difficulty coordinating the muscle movements necessary to say those words.

• He or she may say something completely different, even made-up words. • For example, a patient may try to say "kitchen," but it may

come out "bipem" or even "chicken."

• The patient may recognize the error and try again, sometimes getting it right, or sometimes saying something else entirely.

• This can become quite frustrating to him or her.

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Symptoms of apraxia of speech• A tendency to grope for words or sounds• Limited ability to make speech sounds automatically• Difficulty putting sounds or syllables together in the correct order to

form words• Incorrect timing of speech movements and their accompanying

sounds• Increased tendency to make errors as the length of words or

sentences increases• Inconsistent speech errors, even when repeating a word that's just

been said• Errors using vowels• A tendency to say a word several times before saying it the right way• Inconsistent or improper use of rhythms, stresses, and inflections of

speech that are used to convey meaning• Somewhat preserved ability to produce "automatic speech" (rote

speech), such as greetings like "How are you?"

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Hickok (2012)• Apraxia of speech (AOS) is a motor speech disorder that seems to

affect the planning or coordination of speech at the level that has been argued to correspond to syllable-sized units.

• The ventral premotor cortex has been implicated in the aetiology of AOS, as has the nearby anterior insula.

• It is worth noting that speech errors in AOS and conduction aphasia are often difficult to distinguish, the difference being most notable in speech fluency, with AOS resulting in more halting, effortful speech.

• The similarity in error type and the distinction in fluency between AOS and conduction aphasia is consistent with the present model if one assumes that the two disorders affect the same level of hierarchical motor control (errors occur at the same level of analysis) but in different components of the circuit (AOS affects access to motor phonological codes and conduction aphasia affects internal feedback control).

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MOTOR CORTEXvBA 4

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Frontal cortex colored

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Somatosensory & motor homunculi

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Motor & somatosensory homunculi

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Orofacial, or buccofacial, apraxia • Orofacial, or buccofacial, apraxia is characterized by a

loss of voluntary control of facial, lingual, pharyngeal and masticatory muscles in the presence of preserved reflexive and automatic functions of the same muscles.

• It is not considered to have much relevance to language.

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Final project• Improve a Wikipedia article about any of the topics

mentioned in class or any other topic broadly related to neurolinguistics.

• Write a short essay explaining what you did and why you did it.

• Print the article before you improve it, highlighting any subtractions.

• Print the article after you improve it, highlighting your additions.

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NEXT TIMEStart ventral stream

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