Mindfulness-based stress reduction (MBSR), described as non-judgemental insight to present-moment experiences, is a form of systematic mindfulness meditation training that offers a manualized 8-week program which aims to improve an individual’s psychological capacities, such as attention control, emotion regulation and altered self-awareness¹. Over the past decade, a number of studies have investigated the relationships between mindfulness meditation and brain structure and function. Many researches showed that the changes in brain structure were associated with the practice training and/or the state of mindfulness meditation². However, most of researches employed cross-sectional studies to investigate the practitioners of long-term meditation experience compared with non-meditators since the effects on brain structures would be readily detectable¹. Therefore, a longitudinal study was conducted in this study to probe the effects of the short-term MBSR program on the brain structures. Specifically, an automatic tract-specific analysis was employed over the whole brain to survey subtle changes in white matter tracts.Study Design: An 8-week MBSR program including meditation course and physical exercise was administered to the novice practitioners who hadn’t received the mindfulness training before. Participants took the MRI examination and psychological questionnaires before and after the MBSR program. Subjects: Fifteen healthy adult novices (Age = 44 ± 11 yrs) received the training in the 8-week MBSR program. Besides, 24 healthy adults who didn’t accept the training of MBSR program were recruited as a control group. MRI examination: T1-weighted imaging and diffusion spectrum imaging (DSI) were obtained on a 3T MRI system (TIM Trio, Siemen). T1-weighted imaging utilized a MPRAGE pulse sequence (TR = 2000 ms, TE = 3 ms, flip angle = 9^o, FOV = 256×256 mm^2, resolution = 1×1×1 mm^3). DSI utilized a pulsed gradient twice-refocused spin-echo diffusion echo planar imaging sequence using a summation of 102 diffusion encoding gradients with the maximum diffusion sensitivity b_max of 4000 s/mm^2. (TR = 9600 ms, TE = 130ms, FOV = 200×200 mm^2, matrix size = 80×80, slice thickness = 2.5 mm). System validation: Since the brain structure changes induced by mindfulness meditation may be so subtle that it could be overwhelmed by the errors of the measurement system, we applied Gage R&R analysis to assess the repeatability of our system³. Data analysis: We used whole brain tract-based automatic analysis (TBAA) to obtain a 2D connectogram for each DSI dataset⁴. The connectogram provides generalized fractional anisotropy (GFA) profiles of 76 white matter tract bundles. Pair t test and effect size were calculated to compare the difference in mean GFA of each tract bundle between the pre- and post- training connectograms. Bonferroni correction was used to address multiple comparisons.Gage R&R analysis showed that the repeatability ratio was below 5.5%, indicating that the measurement was stable and consistent over data that were measured repeatedly. There was significant difference in three white matter tracts, right auditory radiation (p value = 2.9 × 10^-4), anterior commissure (p value = 2.38 × 10^-7) and posterior commissure (p value = 1.56 × 10^-4), in the novice practitioners, whereas no significant difference was found in the control group (Table 1). These tracts showed increased mean GFA values after the MBSR program (Figure 1) with high magnitude of effect sizes (Figure 2).We have identified 3 tract bundles that are significantly modulated by short-term MBSR training. The altered white matter tracts might be related to auditory perception (right auditory radiation), emotional communication (anterior commissure) and visual-linked influence (posterior commissure). Further works will be conducted to investigate the functional and behavioral significance of these white matter changes.