The goal of this project was to determine whether MRI can detect the effects of short-term and long-term training on the brain. However, this study led to an incidental finding

related to changes of diffusion measures as a function of time of day.

Contribution: Contributed to the statistical analysis of data collected for this project. The data included multiple scans (eight scans) from 21 subjects acquired during morning and afternoon sessions. The repeated nature of this data required the use of mixed-effects model.

Findings: Our results suggest that mean diffusivity, as measured using the conventional monoexponential tensor model tends to increase systematically from morning to afternoon scans, while a similar increase or a decrease was not evident in pairs of morning or evening scans. The dual compartment analysis revealed that the increase in diffusivity measures from AM to PM was driven by an increase in the volume fraction of CSF-like free water. Importantly, the removal of the contribution from CSF compartment, completely eliminated the apparent increase in trace from AM to PM.

Papers/abstracts: Second author on the following articles: Trefler et al. NeuroImage 2016, and another article under review with NeuroImage by Thomas et al.