CONICET | Buscador de Institutos y Recursos Humanos

Motor adaptation is a type of motor learning that allows maintaining accurate movements in the presence of environmental or internal sensory perturbations by adjusting motor output. The neural substrates of motor adaptation have been extensively explored in human and non-human primates during acquisition. Yet, when interested in identifying plastic changes associated with learning, the ?online? approach is limited by kinematics and dynamics confounds that are very difficult to control for. In this study, we used resting-state fMRI, an offline experimental approach, to characterize the time course of changes in functional connectivity triggered by visuomotor adaptation, throughout a 24 h period. Twenty two normal subjects performed a visuomotor task that required hitting 8 visual targets using a joystick. Experimental subjects (n = 11) did so under a 40 degree clockwise rotation, whereas no perturbation was applied to controls (n = 11). A total of six resting-state runs were acquired following a standard resting-state protocol. One of them was acquired before adaptation (baseline), and the remaining five runs 15min, 1h, 3h, 5.5h and 24 h after adaptation. After standard fMRI preprocessing, data was denoised using ICA and bandpass filtered between 0.08 and 0.009Hz. Twenty-two regions of interest (ROIs) of 5mm ratio were chosen based on previous functional studies carried out during visuomotor learning. Time series were extracted for these ROIs and correlated with each other for each run and each subject. A multivariate statistical approach (PLS, Mcintosh and Bookstein, 1996) was then used to identify a brain pattern that distinguished experimental and control groups based on the time course of functional connectivity. The analysis revealed that the connectivity of the right posterior cerebellum (lobule VIII), left putamen, right inferior frontal gyrus and left ventral premotor cortex increased as a function of time for the control group. In contrast, the connectivity between the posterior parietal cortex and i) the left primary motor cortex, ii) the left dorsal premotor cortex and iii) the left somatosensory cortex increased as a function of time for the experimental group. The level of connectivity between these regions peaked 5.5 h after adaptation and decreased thereafter. We hypothesize that the connections strengthened during visuomotor adaptation underlie motor memory consolidation associated with this type of learning. References: Mcintosh and Bookstein (1996). Neuroimage;3 (3 Pt 1):143-57