When motor performance was recovered, we observed a significant activation with respect to baseline in subcortical structures belonging to different BG circuits (putamen and globus pallidus), involving the limbic system functionally interacting with the BG (amygdala). Then, to assess whether the BG activation was exclusively related to the fatigue and recovery processes or to increasing automatism in motor performance, a control fMRI experiment based on a shorter motor task duration was carried out on 14 healthy subjects. In this case, the task repetition did not induce decreased performance, and no significant effect on the BOLD signal change was found in BG regions of interest with respect to baseline.
All these findings suggest that motor and non-motor BG circuits run parallel and converge in a common motor path to successfully compensate motor performance deterioration in a central fatigue condition.