[en] Magnetic resonance imaging (MRI) allows the observation of the major white matter fiber tracts in the brain. It can thus be used in many applications to have a better understanding of the development of healthy and pathological brains and to study the effect of potential therapeutic treatments. In order to observe these fibers, one must combine a today well-controlled MRI acquisition with a data processing procedure that is still under investigation for many research projects. To characterize those fibers whose diameters are only a few microns wide, the MRI spatial resolution must be raised beyond the spatial resolution of the acquisition. This super-resolution achievement can be obtained by combining biophysical models with several measures of the MRI signal. Together, one can gain access to axon diameter measures for example, as was done by Assaf in 2008 (AxCaliber approach). One of the interests of this measure is its correlation with the conduction velocity of the electric signals (Horowitz 2015). These methodological developments are mainly done in human research. However, many animal models are used to understand the healthy as well as the pathological brains. In the context of a collaboration between team UNIRS of NeuroSpin (Cyril Poupon) and team 5 of GIN (Grenoble Institute of Neuroscience) (Emmanuel Barbier), we have initiated the transfer for the mouse of the tools currently used for human. (author)