University of Western Ontario - Electronic Thesis and Dissertation Repository


Master of Science




Dr. Daniel Ansari


The current study uses diffusion tensor imaging to test whether individual differences in white matter predict performance on the math subtest of the preliminary Scholastic Aptitude Test (PSAT). Grade 10 and 11 PSAT scores were obtained from 30 young adults (ages 17- 18) with wide-ranging math achievement levels. Tract based spatial statistics was used to examine the correlation between PSAT math scores, fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (AD). FA in left parietal white matter was positively correlated with math PSAT scores (specifically in the left superior longitudinal fasciculus, left superior corona radiata, and left corticospinal tract). Furthermore, RD, but not AD, was correlated with PSAT math scores in these white matter microstructures. The negative correlation with RD suggests increased myelination in participants with higher PSAT math scores. Individual differences in FA and RD may reflect variability in experience dependent plasticity over the course of learning and development.