Structural brain changes occur in a complex manner throughout life, and understanding healthy brain development is crucial for the study of brain abnormalities in various conditions. Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging technique that provides information about tissue microstructure not accessible via conventional imaging methods. In this dissertation, DTI is used to assess typical brain development, brain abnormalities in fetal alcohol spectrum disorder (FASD), and relationships between cognition and brain structure in both populations.
Cross-sectional and longitudinal DTI studies were used to measure brain maturation from childhood to adulthood. Significant, nonlinear changes of diffusion parameters were noted across the brain, with regional variation in the timing and magnitude of development. Most regions experienced rapid maturation during childhood and adolescence, reached a developmental peak during adulthood, and then, during senescence, underwent a reversal of structural changes that occurred more gradually than the initial development. The genu and splenium of the corpus callosum had the earliest development, while frontal-temporal connections and the corticospinal tracts showed the most prolonged maturation trajectories.
DTI was also used to examine brain abnormalities in children with FASD, an acquired brain disorder associated with numerous cognitive, behavioural, and emotional difficulties. DTI revealed widespread differences in children with FASD when compared to healthy controls, suggesting extensive structural brain damage.
Finally, significant relationships between cognitive abilities and brain structure were observed in both populations. Brain lateralization of a frontal-temporal pathway correlated with two specific cognitive abilities in typically-developing children. Additionally, a significant relationship between brain structure and mathematical ability was observed in the left parietal lobe of children with FASD. Preliminary results demonstrating reading-brain structure correlations in both healthy and FASD groups are also presented.
In conclusion, DTI has shown significant age-related changes in the typically-developing human brain, abnormalities in children with FASD, and correlations between brain structure and cognition in both populations. Normative DTI studies such as the ones presented here are important to establish healthy milestones of brain development and degradation, which may then be used to understand abnormalities in a variety of conditions, including FASD.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1259 |
| Date | 11 1900 |
| Creators | Lebel, Catherine |
| Contributors | Beaulieu, Christian (Biomedical Engineering), Thompson, Richard (Biomedical Engineering), Phillips, Linda (Canadian Centre for Research on Literacy), Wilman, Alan (Biomedical Engineering), Gross, Donald (Neurology), Alexander, Andrew (Medical Physics, University of Wisconsin) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 17468474 bytes, application/pdf |
| Relation | C. Lebel, S. Caverhill-Godkewitsch, C. Beaulieu. Age-Related Regional Variations of the Corpus Callosum Identified by Diffusion Tensor Tractography. NeuroImage 52 (1): 20-31, August 1, 2010., C. Lebel, C. Rasmussen, K. Wyper, G. Andrew, and C. Beaulieu. Brain Microstructure is Related to Math Ability in Children with Fetal Alcohol Spectrum Disorder. Alcoholism: Clinical and Experimental Research 34 (2): 354-363, Feb 2010., C. Lebel and C. Beaulieu. Lateralization of the Arcuate Fasciculus from Childhood to Adulthood and its Relation to Cognitive Ability in Children. Human Brain Mapping 30 (11): 3563-73, Nov 2009., C. Lebel, C. Rasmussen, K. Wyper, L. Walker, G. Andrew, J. Yager, and C. Beaulieu. Brain Diffusion Abnormalities in Children with Fetal Alcohol Spectrum Disorder. Alcoholism: Clinical and Experimental Research 32 (10): 1732-40, Oct 2008., C. Lebel, L. Walker, A. Leemans, L. Phillips, C. Beaulieu. Microstructural Maturation of the Human Brain from Childhood to Adulthood. NeuroImage 40 (3): 1044- 55, April 15, 2008., C. Lebel, M. Gee, R. Camicioli, M. Wieler, W. Martin, C. Beaulieu. Diffusion Tensor Imaging of Brain White Matter Changes Across the Lifespan. International Society for Magnetic Resonance in Medicine 18th Annual Meeting, Stockholm, Sweden. May 2010., C. Lebel, C. Rasmussen, K .Wyper, G. Andrew, C. Beaulieu. White Matter Structure Correlates with Reading Ability in Healthy Subjects and Those with Fetal Alcohol Spectrum Disorder. International Society for Magnetic Resonance in Medicine 18th Annual Meeting, Stockholm, Sweden. May 2010., C. Lebel and C. Beaulieu. Longitudinal Diffusion Tensor Imaging of Healthy Brain Development in Children. Presented at the International Society for Magnetic Resonance in Medicine 17th Annual Meeting, Honolulu, Hawaii. April 2009. |
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