Neural Substrates of Speech Flashcards
What is speech?
Verbal expression of thoughts and feelings using sound patterns decodable by listeners who share a common language
Speech is ____motor
Sensori
What are the 4 subsystems that comprise speech?
Respiration
Phonation
Articulation
Velopharyngeal (resonation)
What is the purpose of the respiratory subsystem?
Provide airflow and pressure needed for sound generation
How is breathing for speech/vocalization different from vegetative breathing?
Quick inspiration, long expiration
Where are the cell bodies of the respiratory subsystem located?
Ventral (anterior) horn of the spinal cord
Where are the cell bodies of the phonatory and velopharyngeal subsystem located?
Nucleus ambiguus CN X
Where are the cell bodies of the oral articulators located?
Facial (CN VII)
Hypoglossal (CN XII)
Trigeminal nucleus (CN V)
What muscles are the most important muscles for speech?
Muscles of inspiration (diaphragm and external intercostal muscles)
What is the key structure of the phonatory subsystem?
Larynx
What is the purpose of the phonatory subsystem for speech?
Creates vibration for acoustic buzz (voicing)
Vibration created by air pressure and flows driving the vocal folds into oscillation
What muscles are involved in voicing of the phonatory subsystem?
Cricothyroid, lateral and posterior cricoarytenoid, thyroarytenoid, interarytenoid
What nucleus is involved in phonation?
Nucleus ambiguus (CN X)
What is the purpose of the oral articulatory subsystem?
Shape the oral and pharyngeal cavities to create a variable resonator
Generate a variety of sounds by constricting the airstream through the vocal tract
The tongue muscles produce …
Most consonants and vowels
The back consonants are produced by what muscles
Palatoglossus (tongue muscle)
Bilabials (p,b,m), labiovelars (w), and labiodentals (f,v) are controlled by ___ nucleus and __ muscles
Facial nucleus, facial muscles
What is the purpose of the velopharyngeal system?
Velopharyngeal port is rapidly opened and closed to meet phonetic needs during articulation
Closing the velopharyngeal port is needed for production of
All vowels and most consonants
Opening the velopharyngeal port is needed for production of
Nasals
What velopharyngeal nerves are involved in speech?
Nucleus ambiguus (CN X)
Pharyngeal plexus (CN IX, X, XI)
Mandibular nerve (CN V) trigeminal motor nucleus`
What motor speech disorder is associated with LMN damage?
Flaccid dysarthria
Flaccid dysarthria is characterized by
Muscle weakness, hypotonia, reduced reflexes, atrophy, fascicualtions
What deficits are common with flaccid dysarthria?
Hypernasality, imprecise consonants, breathiness, monopitch, harsh or hoarse voice quality, short phrases
Flaccid dysarthria is typically caused by
CN damage (stroke, tumor, TBI), degenerative diseases like ALS
What motor speech disorder is associated with upper motor neuron damage?
Spastic dysarthria
Spastic dysarthria is characterized by …. most prevalent with …..
Increased muscle tone, hyperreflexia, spasticity
Bilateral UMN damage
What speech characteristics are common with spastic dysarthria?
Excess and equal stress, slow rate, imprecise consonants, distorted vowels, monopitch, monoloudness, impact on prosody, nasal, hoarse
What subcortical structures are involved in speech?
Reticular formation
Periaqueductal grey
Thalmus
Basal ganglia
Cerebellum
What subcortical structures are involved in vocalization?
Periaqueductal grey (modulatory role) and reticular formation (muscle activity), both in brainstem
What are the subcortical structures involved in speech that are in the thalamus?
VPM: somatosensory info from head and neck to primary somatosensory cortex
VPL: somatosensory info from chest wall to primary somatosensory cortex
MGN: auditory information to primary auditory cortex of temporal lobe
What subcortical structures involved in speech are in the basal nuclei?
Collection of interconnecting nuclei
1. Motor Circuit (important for movement sequences)
2. Executive/cognitive circuit (important for buffering and sequencing long utterances)
3. Emotional/motivation (providing urge to speak)
What is hyperkinetic dysarthria?
Caused by damage to basal nuclei, issue with direct pathway
Why does hyperkinetic dysarthria cause more movement?
Overactivity of the direct pathway provides strong input to the thalamus = strong thalamic drive to motor cortical areas for movement leading to excessive movement
What is hypokinetic dysarthria?
Caused by damage to basal nuclei
Issue with indirect pathway
Why does hypokinetic dysarthria cause less movement?
Indirect pathway dominance leads to suppression in the movement
Subcortical structures involved in speech: Cerebellum function
Important for control of skilled and precise movement
Coordinates both covert and overt speech
What happens to speech with damage to the cerebellum?
Ataxic dysarthria
The key cortical structures associated with speech are housed in the ____ lobes
Temporal, frontal, parietal
Neurons within the primary motor cortex send projections directly onto LMN located in the brainstem via the ___ tract and the spinal cord via the ___ tract
Corticonuclear
Corticospinal
Primary somatosensory cortex is located within ___ lobe immediately ____ to central sulcus
Parietal
Posterior
Primary somatosensory cortex receives proprioceptive and tactile information from the ___ side of the body via the VPL nucleus of the thalamus for structures below the ___ and VPM nucleus for ____ and ___ regions
Contralateral
Neck
Head, neck
Broca’s area is located in
Inferior frontal gyrus
What is Broca’s area responsible for?
Speech motor control, semantic and syntactic processing of language and reading
Damage to Broca’s area leads to
Apraxia of speech (difficulty programming speech motor movements in absence of motor weakness)
Broca’s aphasia (difficulties expressing oneself using language)
What is the function of supplementary motor areas for speech?
Planning of speech and phonemes
What happens with damage to supplementary motor areas of speech?
Apraxia with incorrect phonemes, impaired ability to say what they want to say (prepositional speech)
What is the function of anterior cingulate cortex? What happens with damage?
Function: initiate speech, control of emotional components of speech
Damage: temporary or permanent akinetic mutism (cannot initiate speech)
What is the function of the supramarginal gyrus?
Language processing, speech motor control
Sound to articulation mapping
Compare expected sensory feedback with actual sensory feedback
Where is the insula?
Deep within the lateral sulcus
What is the function of the insula?
Motivational and affective influence over speech and language
Programming and generation of speech movements
