Abstract
The purpose of this study was to examine sex differences in the maturation of white matter during adolescence ( 12 to 18 years of age). We measured lobular volumes of white matter and white-matter "density" throughout the brain using T1-weighted images, and estimated the myelination index using magnetisation-transfer ratio (MTR). In male adolescents, we observed age-related increases in white-matter lobular volumes accompanied by decreases in the lobular values of white-matter MTR. White-matter density in the putative cortico-spinal tract (pCST) decreased with age. In female adolescents, on the other hand, we found only small age-related increase in white-matter volumes and no age-related changes in white-matter MTR, with the exception of the frontal lobe where MTR increased. White-matter density in the pCST also increased with age. These results suggest that sex-specific mechanisms may underlie the growth of white matter during adolescence. We speculate that these mechanisms involve primarily age-related increases in axonal calibre in males and increased myelination in females. (C) 2009 Elsevier Inc. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 1055-1066 |
| Number of pages | 12 |
| Journal | Neuroimage |
| Volume | 45 |
| Issue number | 4 |
| Early online date | 24 Jan 2009 |
| DOIs | |
| Publication status | Published - 1 May 2009 |
Keywords
- adult human brain
- corpus-callosum
- magnetization-transfer
- morphometric analysis
- in-vivo
- MRI
- dimorphism
- childhood
- architecture
- expression