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Neurolinguistic Staudacher

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    Representation of multiple

    languages in human brain

    Staudacher Veronika

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    Presented Paper

    Kim, Relkin, Lee, Hirsch. (1997) Distinct cortical areas

    associated with native and second languages.

    Nature ,vol. 338: p. 171

    174.

    Research at the Department of Neurology and

    Neuroscience, Cornell University Medical College,

    New York

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    Overview

    Methods of investigation

    a) Imaging

    b) Analysis and subjects (test persons)

    c) Task

    Results of representation in brain areas of

    a) native language

    b) second language (early & late bilinguals)

    Summary and Conclusions

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    Method of investigation

    fMRI: 1.5-tesla magnetic resonance

    scanner, with fixed head position

    16 slices of brain (4.5 - 4.7 mm )

    Areas of interest:* the inferior frontal gyrus (=anteriorlanguage region; Brocas area incl.

    Brodmanns 44 +46)

    * the superior temporal gyrus

    (=posterior language region; Wernickesarea incl. Brodmanns 22)

    30 images, one every 3 sec., 10 during

    baseline period, 10 during a stimulation or task period, 10

    baseline again

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    Analysis and Subjects

    2 identical runs with each language, native and a secondlanguage

    Statistical analyses of changing signals between baseline and

    stimulation periods

    12 healthy multilingual volunteers, 9 male, 3 females

    Right-handed or ambidextrous

    Mean age 29.3 years

    6 early bilinguals (parents speak one language, kids& friendsanother one, or parents spoke 2 languages)

    6 late bilinguals (L2 in early adulthood, 11.2 years, lived in

    country of L2)

    Alltogether 10 languages represented, equal fluency

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    Task

    Persons were prepared before starting

    Describe events of the previous day (morning,

    afternoon, nightsignals were taken)

    Sentences had to be generated silently (internal

    speech) to avoid head movement

    Briefing before task in which language the person

    should be speaking silently, because Languages were altered during session to avoid

    habituation

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    Results

    Focus of observations on Brocas and Wernickes

    areas, axial slice

    Typical late bilingual: anterior language

    area (Inferior frontal gyrus, Brodmanns 44)green box:red: significant activity during native

    language (Engl.)

    yellow: activity during second

    language (French)

    2 centers of activation(+), separated

    7.9 mm

    Result: 2 separated areas for each language

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    Results

    Late bilinguals: distinct areas of activation in Brocas

    area (anterior) for different languages

    Examples of bilinguals:

    red: significant activity during native language

    yellow: activity during second language

    2 centers of activation(+)

    various distances according to language

    combinations

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    Results

    Late bilingual: posterior language area (superior temporalgyrus, Brodmanns 22)

    green box:

    red: significant activity during

    native language (Engl.)yellow: activity during second

    language (French)

    orange: common area for native

    and second language

    2 centers of activation(+),

    separated only 1.1 mm

    Result: similar or identical

    cortical regions serve

    both languages

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    Results

    Early bilingual (e.g. English, Turkish): : in posterior

    language area (superior temporal gyrus, Brodmanns 22)

    green box

    red: significant activity Turkish language task

    yellow: activity English language task

    orange: common voxels for both languages

    2 centers of activation(+), separated only 2.3 mm,

    within

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    Results

    Result: Late acquisition of L2 = tendency of spatially distinction in Brocas area,

    little or no separation in Wernickes area (be it early or late acquisition)

    Late bilinguals Early bilinguals

    Brocas Area:

    Mean distance of

    center-of-mass

    6.43 mm 1.53 mm

    Number of voxels Equal for each

    language,separated

    multiple common

    voxels

    Wernickes area:

    Mean distance of

    center-of-mass

    1.95 mm 1.58 mm

    Number of voxels Different for each language

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    Conclusions

    Age of language acquisiton may be a significant factor for the

    functional organization in brain.

    Children can discriminate all phonetical differences at the

    beginning of their life, but then may adapt the acoustic space

    in brain to their native languages.

    Adjacent cortical areas are used for second language learning

    as an adult.

    The younger a child, when learning a second language, the

    less distinction in brain (PET study: average age 7.9 years).

    Further questions rise concerning Brocas role in processing

    the phonetic structure of different languages.

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    Thank you!

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