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Phonological processing in deaf signers and the impact of age of first language acquisition.

MacSweeney M, Waters D, Brammer MJ, Woll B, Goswami U - Neuroimage (2008)

Bottom Line: This, we suggest, is due to increased reliance on the articulatory component of speech when the auditory component is absent.With regard to age of first language acquisition, non-native signers activated the left inferior frontal gyrus more than native signers during the BSL task, and also during the task performed in English, which both groups acquired late.This is the first neuroimaging demonstration that age of first language acquisition has implications not only for the neural systems supporting the first language, but also for networks supporting languages learned subsequently.

View Article: PubMed Central - PubMed

Affiliation: Behavioural and Brain Sciences Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. m.macsweeney@ich.ucl.ac.uk

ABSTRACT
Just as words can rhyme, the signs of a signed language can share structural properties, such as location. Linguistic description at this level is termed phonology. We report that a left-lateralised fronto-parietal network is engaged during phonological similarity judgements made in both English (rhyme) and British Sign Language (BSL; location). Since these languages operate in different modalities, these data suggest that the neural network supporting phonological processing is, to some extent, supramodal. Activation within this network was however modulated by language (BSL/English), hearing status (deaf/hearing), and age of BSL acquisition (native/non-native). The influence of language and hearing status suggests an important role for the posterior portion of the left inferior frontal gyrus in speech-based phonological processing in deaf people. This, we suggest, is due to increased reliance on the articulatory component of speech when the auditory component is absent. With regard to age of first language acquisition, non-native signers activated the left inferior frontal gyrus more than native signers during the BSL task, and also during the task performed in English, which both groups acquired late. This is the first neuroimaging demonstration that age of first language acquisition has implications not only for the neural systems supporting the first language, but also for networks supporting languages learned subsequently.

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(A) Main effect of Group: non-native signers engaged the left inferior frontal gyrus to a greater extent than native signers. Critically this was the case during both the location and rhyme tasks (see text). (B) A significant Group × Task interaction was also identified in the left posterior IFG/precentral gyrus. Non-native signers recruited this region to a similar degree during both rhyme and location tasks. Native signers engaged this region more during the rhyme task, performed in English which was learned late, than the location task performed in their native language (see text). Activated voxels up to 20mm beneath the cortical surface are displayed. Plots represent the mean % signal change across all voxels in the activated cluster within each group of participants. Error bars represent the standard error of the mean.
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fig5: (A) Main effect of Group: non-native signers engaged the left inferior frontal gyrus to a greater extent than native signers. Critically this was the case during both the location and rhyme tasks (see text). (B) A significant Group × Task interaction was also identified in the left posterior IFG/precentral gyrus. Non-native signers recruited this region to a similar degree during both rhyme and location tasks. Native signers engaged this region more during the rhyme task, performed in English which was learned late, than the location task performed in their native language (see text). Activated voxels up to 20mm beneath the cortical surface are displayed. Plots represent the mean % signal change across all voxels in the activated cluster within each group of participants. Error bars represent the standard error of the mean.

Mentions: No regions were recruited to a greater extent by native than non-native signers. In contrast, non-native signers recruited the left inferior frontal cortex to a greater extent than native signers (see Fig. 5A; 5.32cm3 volume; X = − 40, Y = 19, Z = 30). This activation extended from the IFG (BA 44/45), into the middle frontal gyrus and precentral gyrus. Follow-up analyses were conducted comparing native and non-native signers on the rhyme and location tasks separately (voxelwise p = 0.025; clusterwise p = 0.005). These analyses confirmed that non-native signers engaged the posterior IFG more than native signers, during both the location task (3.45cm3 volume; X = − 40, Y = 15, Z = 30) and the rhyme task (3.74cm3 volume; X = − 40, Y = 7, Z = 23).


Phonological processing in deaf signers and the impact of age of first language acquisition.

MacSweeney M, Waters D, Brammer MJ, Woll B, Goswami U - Neuroimage (2008)

(A) Main effect of Group: non-native signers engaged the left inferior frontal gyrus to a greater extent than native signers. Critically this was the case during both the location and rhyme tasks (see text). (B) A significant Group × Task interaction was also identified in the left posterior IFG/precentral gyrus. Non-native signers recruited this region to a similar degree during both rhyme and location tasks. Native signers engaged this region more during the rhyme task, performed in English which was learned late, than the location task performed in their native language (see text). Activated voxels up to 20mm beneath the cortical surface are displayed. Plots represent the mean % signal change across all voxels in the activated cluster within each group of participants. Error bars represent the standard error of the mean.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2278232&req=5

fig5: (A) Main effect of Group: non-native signers engaged the left inferior frontal gyrus to a greater extent than native signers. Critically this was the case during both the location and rhyme tasks (see text). (B) A significant Group × Task interaction was also identified in the left posterior IFG/precentral gyrus. Non-native signers recruited this region to a similar degree during both rhyme and location tasks. Native signers engaged this region more during the rhyme task, performed in English which was learned late, than the location task performed in their native language (see text). Activated voxels up to 20mm beneath the cortical surface are displayed. Plots represent the mean % signal change across all voxels in the activated cluster within each group of participants. Error bars represent the standard error of the mean.
Mentions: No regions were recruited to a greater extent by native than non-native signers. In contrast, non-native signers recruited the left inferior frontal cortex to a greater extent than native signers (see Fig. 5A; 5.32cm3 volume; X = − 40, Y = 19, Z = 30). This activation extended from the IFG (BA 44/45), into the middle frontal gyrus and precentral gyrus. Follow-up analyses were conducted comparing native and non-native signers on the rhyme and location tasks separately (voxelwise p = 0.025; clusterwise p = 0.005). These analyses confirmed that non-native signers engaged the posterior IFG more than native signers, during both the location task (3.45cm3 volume; X = − 40, Y = 15, Z = 30) and the rhyme task (3.74cm3 volume; X = − 40, Y = 7, Z = 23).

Bottom Line: This, we suggest, is due to increased reliance on the articulatory component of speech when the auditory component is absent.With regard to age of first language acquisition, non-native signers activated the left inferior frontal gyrus more than native signers during the BSL task, and also during the task performed in English, which both groups acquired late.This is the first neuroimaging demonstration that age of first language acquisition has implications not only for the neural systems supporting the first language, but also for networks supporting languages learned subsequently.

View Article: PubMed Central - PubMed

Affiliation: Behavioural and Brain Sciences Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. m.macsweeney@ich.ucl.ac.uk

ABSTRACT
Just as words can rhyme, the signs of a signed language can share structural properties, such as location. Linguistic description at this level is termed phonology. We report that a left-lateralised fronto-parietal network is engaged during phonological similarity judgements made in both English (rhyme) and British Sign Language (BSL; location). Since these languages operate in different modalities, these data suggest that the neural network supporting phonological processing is, to some extent, supramodal. Activation within this network was however modulated by language (BSL/English), hearing status (deaf/hearing), and age of BSL acquisition (native/non-native). The influence of language and hearing status suggests an important role for the posterior portion of the left inferior frontal gyrus in speech-based phonological processing in deaf people. This, we suggest, is due to increased reliance on the articulatory component of speech when the auditory component is absent. With regard to age of first language acquisition, non-native signers activated the left inferior frontal gyrus more than native signers during the BSL task, and also during the task performed in English, which both groups acquired late. This is the first neuroimaging demonstration that age of first language acquisition has implications not only for the neural systems supporting the first language, but also for networks supporting languages learned subsequently.

Show MeSH