Neuroscience of speech and language

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Neuroscience of speech and language

• BBS 4032
• 1 why (and how) neuroscience?

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• Youll have to leave out the brain but that
  still leaves the mind, so it doesnt solve your
  problem. (Neil Smith)
• If the human mind were simple enough to
  understand, wed be too simple-minded to
  understand it. (Emerson Pugh)

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Why neuroscience?

• The study of anatomical structures and
  physiological processes of the nervous system
• Understanding the normal nervous system makes it
  possible for us to identify sites of structural
  and functional abnormality
• Nervous system abnormalities are indicated by
  sensory, motor, cognitive and behavioral changes
  including changes in speech and language
• The brain is the source of all speech and
  language behavior

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Why neuroscience?

• To understand normal neuroanatomy and
  neurophysiology
• To understand how normal function has been
  impaired
• To understand the etiology of the impairment
• To better structure rehabilitation

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Speech vs Language

• Speech a motor process
• Production of sounds and sequences to transmit
  meaning
• LHS Brocas area, primary and supplementary
  motor areas
• Language formulation, comprehension and use
• LHS posterior frontal, temporal, parietal lobes
  arcuate fasciculus, angular gyrus, supramarginal
  gyrus

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Stages of communication
Building a message
Aphasia
Apraxia
Programming for speech
Dysarthria
Execution
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Level of impairment - functional

• Aphasia comprehension or formulation of
  language is impaired
• Speech impairments
• Apraxia of speech
• Articulatory inaccuracy
• Prosodic changes
• Dysarthria
• Respiratory, phonatory, resonatory, articulatory
  inaccuracies / insufficiencies

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Etiologies of communication disorders

• Trauma
• Vascular disturbance, anoxia
• Tumor
• Infection
• Toxicity
• Metabolic deficiency
• Degenerative disease
• Idiopathic

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Plasticity

• Adaptive ability of the brain to reorganize and
  modify its function, to cope with damage /
  changes in structure
• Nerve regeneration
• Migration of function
• Rehabilitation
• Teach new ways to perform old tasks
• Attempt to create new pathways

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Review Some important brain structures
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Functional anatomy some important cortical
regions
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Investigating brain function

• How do we know what we know about the brain and
  its functions?
• Animal studies
• but many of the functions we need information
  about are unique to humans speech, language
• Imaging studies
• Lesion deficit studies

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Imaging studies
EEG
electromagnetic
MEG
Noninvasive functional brain recording
fMRI
hemodynamic / metabolic
PET
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EEG

• Electrical fields generated by dendritic synapses
  (thalamo-cortical circuits)

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MEG

• Magnetic fields associated with electrical
  activity in the brain

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PET

• Positron Emission Tomography
• A fast-decaying radioactive isotope is injected
  into the bloodstream, then traced as it decays

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(f)MRI

• (functional) Magnetic Resonance Imaging
• BOLD response
• Higher O2 changes magnetic properties of
  hemoglobin can be picked up by the imaging
  system

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Lesion studies

• Experiments in nature
• Windows on the mind

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This course

• Pathways for different speech and language
  subprocesses which regions are involved, and
  what can go wrong
• Speech perception, speech production
• Language morphosyntax, meaning
• How the brain develops for language, and what we
  know about the neural correlates of developmental
  language difficulties