75 - Sex- and age-related volumetric differences in white matter during early brain development in rhesus macaques using diffusion MRI tractography

Poster Board Number: 75
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

Jose Luis Alatorre Warren - Lifespan Changes in Brain and Cognition; Alpen Ortug, PhD - Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School; Emi Takahashi, PhD - Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School

Abstract Body : The rhesus macaque (macaca mulatta) is an extremely important model for biomedical research, as it is phylogenetically close to our species and shares numerous anatomical features. They have also been valuable in studies of brain development. However, drawing direct comparisons is challenging in brain developmental research, as rhesus macaques, for example, nearly reach full brain size within the initial 6-9 months of life, while humans continue to grow until around age 5 and beyond. Thus, it is crucial to understand the similarities and differences between rhesus macaques and humans for valid translational research studies. Within humans, sex- and age-related differences in the volume of white matter (WM) tracts during early development have been linked to behavior and cognitive maturation. Despite these findings, there is a lack of understanding of the early WM development in rhesus macaques, including within the context of sexual dimorphism. Here, we used longitudinal diffusion MRI from the open-access UNC-Wisconsin Rhesus Macaque Neurodevelopmental Database to identify major WM tracts in macaques aged 2 weeks to 36 months. The tractography pathways were reconstructed using Diffusion Toolkit, and a total of 17 major WM tracts were identified, with manually placed regions of interest (ROIs) in TrackVis as determined from anatomical landmarks. The identified tractography pathways were further refined through interactive tools in DSI Studio, including the removal of artifacts to enhance data quality. We applied statistical methods including t-tests and ANOVA with Bonferroni correction to account for multiple comparisons. Interestingly, our findings revealed no statistically significant volumetric differences in WM tracts between males and females throughout this developmental period. However, we found age-related changes in several WM tracts, namely the corpus callosum, right inferior fronto-occipital fasciculus, right cingulum, and right fornix. Future research directions include the incorporation of various diffusion indices within this data to further investigate these developmental patterns and compare them to humans. In addition, there is a clear opportunity to use the manually extracted data to develop automated tools for the identification and analysis of WM tracts in rhesus macaques. Our study focuses on the early development of macaques and provides a comparative framework for translational research in humans.