Abstract
Introduction
Previous studies have shown a relationship between corpus callosum morphology (CC) and the lateralization of language processing. Various parts of the CC are associated with language. We compare four bundles arising from the mid-sagittal CC and connecting to the primary motor cortex, the orbital, parietal and temporal lobes, respectively, in simultaneous bilinguals, sequential bilinguals and monolinguals.
Materials and Methods
A 3T MR system (Philips Achieva Release 2.5) with an 8 channel SENSE head coil was used.12 monolingual,15 sequential bilinguals and 15 simultaneous bilinguals were scanned. Simultaneous bilinguals acquired both languages from birth at home, while sequential bilinguals acquired their second language at school.
Scan parameters: SS-SEEPI, 15 non-collinear diffusion gradient directions ,b= 700 s/mm2,TR/TE=6484ms/60ms, FOV=224x224x120 mm3,60 oblique axial 2mm slices, scan duration=454s. Figure 1 shows 4 bundles: motor cortex, orbital, parietal and temporal lobes. Mean fractional anisotropy (FA) in the bundles was calculated for each subject using DTIstudio (Johns Hopkins University, Baltimore, USA). One-way ANOVA with Bonferroni post-hoc testing was undertaken to compare the mean FA values between groups. A P-value of less than 0.05 was considered significant.
Results and Discussion
FA values are summarized in Table1. The mean FA of fibers connecting the anterior part of the CC to the orbital lobe is higher in monolinguals (Table2). No significant difference between the three groups could be found for the FA values of the 3 other bundles.
These results support the hypothesis that the structure of the CC is different between bilinguals and monolinguals. The study demonstrates that DTI can help understanding structural differences between the white matter of bilingual and monolingual brains.
Figure 1 Left: Regional subdivision of the mid-sagittal CC; Right: Fibers to the motor cortex (yellow) and the orbital (green), parietal (orange) and temporal (pink) lobes.
Simultaneous bilinguals Sequential bilinguals Monolinguals
Orbital 0.589±0.024 0.595±0.025 0.613±0.022
Primary motor cortex 0.577±0.020 0.582± 0.018 0.571±0.018
Parietal 0.591±0.024 0.588±0.021 0.586±0.019
Temporal 0.635±0.033 0.627±0.028 0.627±0.025
Simultaneous vs. Sequential Simultaneous vs. Monolingual Sequential vs. Monolingual
P (ANOVA-Post hoc) 0.823 *0.031 *0.043
Previous studies have shown a relationship between corpus callosum morphology (CC) and the lateralization of language processing. Various parts of the CC are associated with language. We compare four bundles arising from the mid-sagittal CC and connecting to the primary motor cortex, the orbital, parietal and temporal lobes, respectively, in simultaneous bilinguals, sequential bilinguals and monolinguals.
Materials and Methods
A 3T MR system (Philips Achieva Release 2.5) with an 8 channel SENSE head coil was used.12 monolingual,15 sequential bilinguals and 15 simultaneous bilinguals were scanned. Simultaneous bilinguals acquired both languages from birth at home, while sequential bilinguals acquired their second language at school.
Scan parameters: SS-SEEPI, 15 non-collinear diffusion gradient directions ,b= 700 s/mm2,TR/TE=6484ms/60ms, FOV=224x224x120 mm3,60 oblique axial 2mm slices, scan duration=454s. Figure 1 shows 4 bundles: motor cortex, orbital, parietal and temporal lobes. Mean fractional anisotropy (FA) in the bundles was calculated for each subject using DTIstudio (Johns Hopkins University, Baltimore, USA). One-way ANOVA with Bonferroni post-hoc testing was undertaken to compare the mean FA values between groups. A P-value of less than 0.05 was considered significant.
Results and Discussion
FA values are summarized in Table1. The mean FA of fibers connecting the anterior part of the CC to the orbital lobe is higher in monolinguals (Table2). No significant difference between the three groups could be found for the FA values of the 3 other bundles.
These results support the hypothesis that the structure of the CC is different between bilinguals and monolinguals. The study demonstrates that DTI can help understanding structural differences between the white matter of bilingual and monolingual brains.
Figure 1 Left: Regional subdivision of the mid-sagittal CC; Right: Fibers to the motor cortex (yellow) and the orbital (green), parietal (orange) and temporal (pink) lobes.
Simultaneous bilinguals Sequential bilinguals Monolinguals
Orbital 0.589±0.024 0.595±0.025 0.613±0.022
Primary motor cortex 0.577±0.020 0.582± 0.018 0.571±0.018
Parietal 0.591±0.024 0.588±0.021 0.586±0.019
Temporal 0.635±0.033 0.627±0.028 0.627±0.025
Simultaneous vs. Sequential Simultaneous vs. Monolingual Sequential vs. Monolingual
P (ANOVA-Post hoc) 0.823 *0.031 *0.043
| Original language | English |
|---|---|
| Pages (from-to) | 476-477 |
| Number of pages | 2 |
| Journal | Magnetic Resonance Materials in Physics, Biology and Medicine |
| Volume | 24 |
| Issue number | ESMRMB 2011 |
| Publication status | Published - Oct 2011 |
| Event | Unknown - Duration: 1 Oct 2011 → … |
Keywords
- DTI
- Bilingualism
- white matter