Cognitive Neuroscience of Language

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Cognitive Neuroscience of Language. Cognitive Neuroscience of Language. Premise 1 : Constituent Cognitive Processes Phonological analysis Syntactic analysis Semantic analysis Premise 2 : Areas of the brain involved in language are not exclusively involved with that function - PowerPoint PPT Presentation

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<ul><li><p>Cognitive Neuroscience of Language*</p></li><li><p>Cognitive Neuroscience of LanguagePremise 1: Constituent Cognitive ProcessesPhonological analysisSyntactic analysisSemantic analysisPremise 2: Areas of the brain involved in language are not exclusively involved with that functionPremise 3: Brain areas involved with language are small and widely distributed &amp; parts of other functional systems</p><p>*</p></li><li><p>Methodolodogy of Cognitive Neuroscience ApproachWernicke-Geschwind model analysis of brain-damaged patientsCog Neuro approach employs a wide array of other techniquesfMRI, PET, TMSFunctional brain imaging studies have revolutionized study of languageCaveat: Correlation Causation*</p></li><li><p>Functional Brain Imaging and Localization of LanguageBevaliers fMRI study of reading sought to establish cortical involvement in readingReading sentences versus control periods (strings of consonants)Areas of activity were tiny and spread outActive areas varied between subjects and trialsActivity was widespread*</p></li><li><p>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 510% of the indicated areas on any particular trial.*</p></li><li><p>Damasios PET Study of NamingDamasio and colleagues (1996) PET study of namingImages of famous faces, animals, and toolsActivity while judging image orientation subtracted from activity while namingLeft temporal lobe areas activated by naming varied with categoryActivity seen well beyond Wernickes area*</p></li><li><p>PET Study of Naming*</p></li><li><p>*</p></li><li><p>Cognitive Neuroscience of DyslexiaDyslexia reading difficulties not due to some other deficit (e.g., vision, intelligence)Developmental dyslexia apparent when learning to readHeritability estimate = 50%More common in boys than girlsAcquired dyslexiaDue to brain damageRelatively rare*</p></li><li><p>Developmental Dyslexia: Causes and Neural MechanismsBrain differences identified, but none seems to play a role in the disorderMultiple types of developmental dyslexia possibly multiple causesVarious subtle visual, auditory, and motor deficits are commonly seenWeight of evidence: deficit of phonological processing rather than sensorimotor processing*</p></li><li><p>Developmental Dyslexia and CultureGenetic component yet the disorder is also influenced by cultureTwice as many English speakers as Italian speakers diagnosed with dyslexiaSound-symbol correspondence in English is more complex and difficult to learn*</p></li><li><p>Cognitive Neuroscience of Deep and Surface DyslexiaTwo procedures for reading aloudLexical using stored information about wordsPhonetic sounding outSurface dyslexia lexical procedure lost, cant recognize wordsDeep dyslexia phonetic procedure lost, cant sound out unfamiliar words*</p></li><li><p>Cognitive Neuroscience of Deep and Surface Dyslexia ContinuedSurface dyslexia loss of visual recognition of words (cannot look and say)Deep (or phonological) dyslexia loss of ability to sound out unfamiliar words or nonwordsDifferent error patterns for surface and deepSurface e.g. trouble with the pronunciation exceptions have or lose Deep: - e.g. quill for quail or hen for chicken*</p></li><li><p>Cognitive Neuroscience of Deep and Surface Dyslexia ContinuedDeep dyslexia extensive damage to left-hemisphere language areasHow is it that lexical procedure is spared?May be housed in left language areas that are sparedMay be mediated by the right hemisphereEvidence for both exists*</p><p>**</p><p>********There**Cognitive researchers have found two strategies for reading: a lexical procedure, used when material is familiar; and a phonetic procedure, used when the words are novel.</p><p>These two strategies led to a better understanding of the two main types of dyslexia produced by brain damage: surface dyslexia occurs when patients lose their lexical skills, whereas deep dyslexia occurs when patients lose their phonetic reading skills.</p><p>**</p></li></ul>

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