Population differences in brain morphology and microstructure among Chinese, Malay, and Indian neonates

Abstract

We studied a sample of 75 Chinese, 73 Malay, and 29 Indian healthy neonates taking part in a cohort study to examine potential differences in neonatal brain morphology and white matter microstructure as a function of ethnicity using both structural T2-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). We first examined the differences in global size and morphology of the brain among the three groups. We then constructed the T2-weighted MRI and DTI atlases and employed voxel-based analysis to investigate ethnic differences in morphological shape of the brain from the T2-weighted MRI, and white matter microstructure measured by fractional anisotropy derived from DTI. Compared with Malay neonates, the brains of Indian neonates' tended to be more elongated in anterior and posterior axis relative to the superior-inferior axis of the brain even though the total brain volume was similar among the three groups. Although most anatomical regions of the brain were similar among Chinese, Malay, and Indian neonates, there were anatomical variations in the spinal-cerebellar and cortical-striatal-thalamic neural circuits among the three populations. The population-related brain regions highlighted in our study are key anatomical substrates associated with sensorimotor functions.

Figure 1. Neonatal structural MRI and DTI atlases.

Rows (A-C) respectively show the axial slices of the T2-weighted MRI, the DTI color map and fractional anisotropy (FA) atlases. The anatomical coordinates of individual axial slices are listed on the bottom of the figure.

Figure 2. Statistical Maps of ethnic group difference in brain morphological shape (A) and fractional anisotropy (B).

The anatomical coordinates of each axial slice are given at the bottom of each panel. Abbreviations: LG – lingual gyrus; PCR – posterior corona radiata; GP – globus pallidus; ALIC – anterior limb of internal capsule; CC – corpus callosum.

Figure 3. Boxplots of mean deformation within each anatomical region extracted from voxel-based analysis on the brain morphological shape (see Figure 2A).

The significant pairwise group differences are indicated using black asterisk.

Figure 4. Boxplots of mean fractional anisotropy (FA) within the anatomical regions extracted from voxel-based analysis on FA (see Figure 2B).

The significant pairwise group difference is indicated using black asterisk.