Abstract
Previous studies have reported training-related changes in MRI-measures of brain structure and function. However, MRI measures can be influenced by factors such as time-of-day (TOD), which may be confounded with pre- and post-training effects. Further, there is limited evidence that any changes are task-specific. Here, in a group of 19 healthy adults scanned over multiple visits, we compared task-specific changes in MRI measures after training in visual and motor tasks, while controlling for TOD. Each visit included scan sessions in the AM and PM. On Visits 1 and 4, participants received no training allowing us to model diurnal changes in MRI measures. On Visits 2 and 3, between the AM and PM scans, participants trained for 90 minutes on a visuo-spatial task (i.e. learning the spatial layout of a racetrack) and left-lateralized motor sequence learning respectively. Multimodal MRI data (Resting state fMRI, T1weighted MRI, Diffusion MRI) were acquired during each scan session. Participants showed significant improvement in behavioral performance in both tasks, after training. Analysis of MRI measures of brain function (e.g. resting state functional connectivity (rsFC)) and structure (e.g. cortical thickness, fractional anisotropy) revealed significant fluctuations in MRI measures of function and structure that were related to physiological changes due to TOD, rather than training. After controlling for the effect of TOD, we found changes in rsFC specific to visuo-spatial learning and motor-sequence learning, although evidence for such specificity was not robust in the structural MRI measures. In addition, we found significant correlations between improvements in behavioral performance and changes in the rsFC, as well as structural measures, but the spatial topography of these regions were different from regions that evinced task-specific changes. In summary, our findings suggest task-specific, training-related changes can be measured using MRI, but highlight the importance of controlling for potential confounds.
Meeting abstract presented at VSS 2018