Tract-based assessment of the subcortical motor network plasticity after stroke

We previously established that uninjured cortical motor network is remodeling in stroke patients with motor deficits [1.2]. Both axonal [1] andmyelin plasticity [2] were, in fact, observed during 6 months longitudinal follow-up. However, the contribution of uninjured subcortical motor circuits in strokerecovery has not been studied yet. Therefore, in this study, we aimed at investigating myelin and axonal plasticity in the subcortical motor networks(SC-MN) contralateral to stroke by applying diffusion spectrum and magnetization transfer imaging. The SC-MS is constituted by connections between thecortical motor area, the basal ganglia and the thalamus, and it essentially consists in three major subcortical networks (figure 1): i) the sensory-motorsub-loop (primary and sensory motor areas -putamen-globus pallidus-ventral lateral thalamic nucleus-motor cortex), ii) the premotor sub-loop (premotordorsal and ventral areas (dPM, vPM)-caudate nucleus-putamen, globus pallidus-ventral anterior thalamic nuleus-premotor cortex iii) the supplementarymotor area (SMA) sub-loop (SMA - putamen and caudatus - globus pallidus-ventral anterior and the ventro-lateral thalamic nuclei-SMA).