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Children with reading disability show brain differences in effective connectivity for visual, but not auditory word comprehension.

Liu L, Vira A, Friedman E, Minas J, Bolger D, Bitan T, Booth J - PLoS ONE (2010)

Bottom Line: BMS yielded the same winning family with modulatory effects on bottom-up connections from the input regions to middle temporal gyrus (MTG) and inferior frontal gyrus(IFG) with inconclusive evidence regarding top-down modulations.The bottom-up effect from the fusiform gyrus (FG) to MTG rather than the top-down effect from IFG to MTG was stronger in TD compared to RD for the visual modality.This study revealed a modality-specific deficit for children with RD in bottom-up effective connectivity from orthographic to semantic processing regions.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China. lilyliu@bnu.edu.cn

ABSTRACT

Background: Previous literature suggests that those with reading disability (RD) have more pronounced deficits during semantic processing in reading as compared to listening comprehension. This discrepancy has been supported by recent neuroimaging studies showing abnormal activity in RD during semantic processing in the visual but not in the auditory modality. Whether effective connectivity between brain regions in RD could also show this pattern of discrepancy has not been investigated.

Methodology/principal findings: Children (8- to 14-year-olds) were given a semantic task in the visual and auditory modality that required an association judgment as to whether two sequentially presented words were associated. Effective connectivity was investigated using Dynamic Causal Modeling (DCM) on functional magnetic resonance imaging (fMRI) data. Bayesian Model Selection (BMS) was used separately for each modality to find a winning family of DCM models separately for typically developing (TD) and RD children. BMS yielded the same winning family with modulatory effects on bottom-up connections from the input regions to middle temporal gyrus (MTG) and inferior frontal gyrus(IFG) with inconclusive evidence regarding top-down modulations. Bayesian Model Averaging (BMA) was thus conducted across models in this winning family and compared across groups. The bottom-up effect from the fusiform gyrus (FG) to MTG rather than the top-down effect from IFG to MTG was stronger in TD compared to RD for the visual modality. The stronger bottom-up influence in TD was only evident for related word pairs but not for unrelated pairs. No group differences were noted in the auditory modality.

Conclusions/significance: This study revealed a modality-specific deficit for children with RD in bottom-up effective connectivity from orthographic to semantic processing regions. There were no group differences in connectivity from frontal regions, suggesting that the core deficit in RD is not in top-down modulation.

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Typically developing (TD) group showed significantly stronger modulatory effects than reading disability (RD) group on the bottom-up connection from fusiform gyrus (FG) to middle temporal gyrus (MTG), but not on the top-down connection from inferior frontal gyrus (IFG) to MTG.This difference was only in the related condition in the visual modality. *, p<0.05.
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pone-0013492-g001: Typically developing (TD) group showed significantly stronger modulatory effects than reading disability (RD) group on the bottom-up connection from fusiform gyrus (FG) to middle temporal gyrus (MTG), but not on the top-down connection from inferior frontal gyrus (IFG) to MTG.This difference was only in the related condition in the visual modality. *, p<0.05.

Mentions: We calculated 2 group (TD, RD) by 2 relatedness (related, unrelated) by 2 coupled region (top-down from inferior frontal gyrus, bottom-up from fusiform gyrus) ANOVAs for the visual modality to investigate modulatory effects to MTG. The ANOVA showed a significant group*relatedness*region (F(1, 22) = 5.530, p = .028) interaction effect, and trends toward group*relatedness (F(1,22) = 3.684, p = .068) and group*region (F(1,22) = 3.298,p = 0.083) interactions. To further understand the three-way interaction, a 2 group by 2 region ANOVA was calculated for related and unrelated conditions separately. These analyses revealed that there was significant main effect of group (F(1,22) = 4.767, p = 0.040) and significant group*region (F(1,22) = 5.630, p = 0.027) interaction effect in the related condition, but not in the unrelated condition. Follow up two-sample t-tests showed that TD group showed a significantly larger modulatory effect than the RD group in the bottom-up connection from FG to MTG (t(22) = 2.304, p = .031), but not in the top-down connection (t(22) = −0.462, p = .649) (See Fig. 1).


Children with reading disability show brain differences in effective connectivity for visual, but not auditory word comprehension.

Liu L, Vira A, Friedman E, Minas J, Bolger D, Bitan T, Booth J - PLoS ONE (2010)

Typically developing (TD) group showed significantly stronger modulatory effects than reading disability (RD) group on the bottom-up connection from fusiform gyrus (FG) to middle temporal gyrus (MTG), but not on the top-down connection from inferior frontal gyrus (IFG) to MTG.This difference was only in the related condition in the visual modality. *, p<0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2963599&req=5

pone-0013492-g001: Typically developing (TD) group showed significantly stronger modulatory effects than reading disability (RD) group on the bottom-up connection from fusiform gyrus (FG) to middle temporal gyrus (MTG), but not on the top-down connection from inferior frontal gyrus (IFG) to MTG.This difference was only in the related condition in the visual modality. *, p<0.05.
Mentions: We calculated 2 group (TD, RD) by 2 relatedness (related, unrelated) by 2 coupled region (top-down from inferior frontal gyrus, bottom-up from fusiform gyrus) ANOVAs for the visual modality to investigate modulatory effects to MTG. The ANOVA showed a significant group*relatedness*region (F(1, 22) = 5.530, p = .028) interaction effect, and trends toward group*relatedness (F(1,22) = 3.684, p = .068) and group*region (F(1,22) = 3.298,p = 0.083) interactions. To further understand the three-way interaction, a 2 group by 2 region ANOVA was calculated for related and unrelated conditions separately. These analyses revealed that there was significant main effect of group (F(1,22) = 4.767, p = 0.040) and significant group*region (F(1,22) = 5.630, p = 0.027) interaction effect in the related condition, but not in the unrelated condition. Follow up two-sample t-tests showed that TD group showed a significantly larger modulatory effect than the RD group in the bottom-up connection from FG to MTG (t(22) = 2.304, p = .031), but not in the top-down connection (t(22) = −0.462, p = .649) (See Fig. 1).

Bottom Line: BMS yielded the same winning family with modulatory effects on bottom-up connections from the input regions to middle temporal gyrus (MTG) and inferior frontal gyrus(IFG) with inconclusive evidence regarding top-down modulations.The bottom-up effect from the fusiform gyrus (FG) to MTG rather than the top-down effect from IFG to MTG was stronger in TD compared to RD for the visual modality.This study revealed a modality-specific deficit for children with RD in bottom-up effective connectivity from orthographic to semantic processing regions.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China. lilyliu@bnu.edu.cn

ABSTRACT

Background: Previous literature suggests that those with reading disability (RD) have more pronounced deficits during semantic processing in reading as compared to listening comprehension. This discrepancy has been supported by recent neuroimaging studies showing abnormal activity in RD during semantic processing in the visual but not in the auditory modality. Whether effective connectivity between brain regions in RD could also show this pattern of discrepancy has not been investigated.

Methodology/principal findings: Children (8- to 14-year-olds) were given a semantic task in the visual and auditory modality that required an association judgment as to whether two sequentially presented words were associated. Effective connectivity was investigated using Dynamic Causal Modeling (DCM) on functional magnetic resonance imaging (fMRI) data. Bayesian Model Selection (BMS) was used separately for each modality to find a winning family of DCM models separately for typically developing (TD) and RD children. BMS yielded the same winning family with modulatory effects on bottom-up connections from the input regions to middle temporal gyrus (MTG) and inferior frontal gyrus(IFG) with inconclusive evidence regarding top-down modulations. Bayesian Model Averaging (BMA) was thus conducted across models in this winning family and compared across groups. The bottom-up effect from the fusiform gyrus (FG) to MTG rather than the top-down effect from IFG to MTG was stronger in TD compared to RD for the visual modality. The stronger bottom-up influence in TD was only evident for related word pairs but not for unrelated pairs. No group differences were noted in the auditory modality.

Conclusions/significance: This study revealed a modality-specific deficit for children with RD in bottom-up effective connectivity from orthographic to semantic processing regions. There were no group differences in connectivity from frontal regions, suggesting that the core deficit in RD is not in top-down modulation.

Show MeSH
Related in: MedlinePlus