Cognitive Neuroscience of
Language
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Cognitive Neuroscience of
Language
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Premise 1: Constituent Cognitive Processes
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Phonological analysis
Syntactic analysis
Semantic analysis
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Premise 2: Areas of the brain involved in
language are not exclusively involved with
that function
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Premise 3: Brain areas involved with
language are small and widely distributed &
parts of other functional systems
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Methodolodogy of Cognitive
Neuroscience Approach
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Wernicke-Geschwind model – analysis of braindamaged patients
Cog Neuro approach employs a wide array of
other techniques
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fMRI, PET,
TMS
Functional brain imaging studies have
revolutionized study of language
Caveat: Correlation ≠ Causation
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Functional Brain Imaging and
Localization of Language
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Bevalier’s fMRI study of reading – sought to
establish cortical involvement in reading
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Reading sentences versus control periods
(strings of consonants)
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Areas of activity were tiny and spread out
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Active areas varied between subjects and trials
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Activity was widespread
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FIGURE 16.16 The areas in which reading-associated increases in activity were observed in
the fMRI study of Bavelier and colleagues (1997). These maps were derived by averaging the
scores of all participants, each of whom displayed patchy increases of activity in 5–10% of the
indicated areas on any particular trial.
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Damasio’s PET Study of
Naming
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Damasio and colleagues (1996) PET study of
naming
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Images of famous faces, animals, and tools
Activity while judging image orientation subtracted
from activity while naming
Left temporal lobe areas activated by naming
varied with category
Activity seen well beyond Wernicke’s area
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PET Study of Naming
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Cognitive Neuroscience of
Dyslexia
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Dyslexia – reading difficulties not due to some other
deficit (e.g., vision, intelligence)
Developmental dyslexia – apparent when learning to
read
 Heritability estimate = 50%
 More common in boys than girls
Acquired dyslexia
 Due to brain damage
 Relatively rare
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Developmental Dyslexia:
Causes and Neural Mechanisms
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Brain differences identified, but none seems
to play a role in the disorder
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Multiple types of developmental dyslexia –
possibly multiple causes
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Various subtle visual, auditory, and motor
deficits are commonly seen
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Weight of evidence: deficit of phonological
processing rather than sensorimotor
processing
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Developmental Dyslexia and
Culture
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Genetic component – yet the disorder is also
influenced by culture
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Twice as many English speakers as Italian
speakers diagnosed with dyslexia
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Sound-symbol correspondence in English is
more complex and difficult to learn
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Cognitive Neuroscience of
Deep and Surface Dyslexia
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Two procedures for reading aloud
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Lexical – using stored information about words
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Phonetic – sounding out
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Surface dyslexia – lexical procedure lost,
can’t recognize words
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Deep dyslexia – phonetic procedure lost,
can’t sound out unfamiliar words
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Cognitive Neuroscience of
Deep and Surface Dyslexia
Continued
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Surface dyslexia – loss of visual recognition
of words (cannot “look and say”)
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Deep (or “phonological”) dyslexia – loss of
ability to “sound out” unfamiliar words or
“nonwords”
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Different error patterns for surface and deep
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Surface – e.g. trouble with the pronunciation
exceptions “have” or “lose”
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Deep: - e.g. “quill” for “quail” or “hen” for “chicken”
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Cognitive Neuroscience of
Deep and Surface Dyslexia
Continued
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Deep dyslexia – extensive damage to lefthemisphere language areas
How is it that lexical procedure is spared?
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May be housed in left language areas that are spared
May be mediated by the right hemisphere
Evidence for both exists
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