title: Micro-structural assessment of short term plasticity dynamics.
abstract: Diffusion MRI enables the non-invasive investigation of neuroplasticity in the human brain. A recent DTI study has shown that a short learning task of only 2 h can yield changes in diffusion parameters. In the current study we aimed to discover whether a biophysical model of diffusion MRI, the CHARMED framework, which models hindered and restricted compartments within the tissue can constitute a more specific method than DTI to study structural plasticity. In addition we set to explore the time scale of the MRI learning-induced-changes. Subjects were scanned with both DTI and CHARMED before and after participating in the same car-racing task. Repetition of a shorter version of the task was done the following week. Results provide additional support to the former discovery of reduction in mean diffusivity after 2 h training using DTI. In addition we show that the CHARMED framework provides a more sensitive method than DTI for discovering microstructural modification. An increase in the fraction of the restricted compartment (Fr) was found after participating in the tasks. Between tasks values of Fr returned to baseline, reflecting the dynamics of structural remodeling. By modeling different compartments in the tissue we suggest that interpretation of the biological processes that induced changes in diffusion is more straightforward, and allows improved detection of the progression of these changes.
authors.affiliation: Department of Neurobiology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ido
authors.initials: I
authors.lastname: Tavor
authors.affiliation: Department of Neurobiology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Shir
authors.initials: S
authors.lastname: Hofstetter
authors.affiliation: Department of Neurobiology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. Electronic address: assafyan@post.tau.ac.il.
authors.forename: Yaniv
authors.initials: Y
authors.lastname: Assaf
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008959:Models, Neurological; D009473:Neuronal Plasticity / Q000502:physiology*; D055815:Young Adult
keywords: CHARMED; DTI; Diffusion MRI; Plasticity; Short-term learning