44. The cerebellum, basal ganglia and motor timing in movement disorders. Behavioral and fMRI study

Abstract

Introduction Published studies demonstrated that the cerebellum and basal ganglia participate in various motor and non-motor task related to prediction. In a series of behavioural and functional imaging studies we studied different populations of patients with movements disorders to clarify the role of the cerebellum and basal ganglia with respect to the motor timing. Methods Specifically, we investigated four different groups: (i) patients with early Parkinson’s disease (PD); (ii) patients with sporadic spinocerebellar ataxia (SCA); (iii) patients with essential tremor (ET); (IV) patients with focal dystonia – cervical dystonia (CD) and (v) matched healthy controls. We used a predictive motor timing task that involved mediated interception of a moving target, and we assessed the effect of movement type (acceleration, deceleration, constant), speed (slow, medium, fast), and angle (0°, 15°, 30°) on performance (hit, early error, late error). Using functional magnetic resonance imaging (fMRI) we evaluated the effect of hits, early errors, late errors – and their contrasts. Results Behavioral: The main results showed that the PD group did not significantly differ from the control group. However, the SCA, ET and CD subjects (severe and mild cerebellar damage, respectively) were significantly worse at interception than the other two groups. We found that the PD patients failed to postpone their action until the right moment and to adapt from one trial to the next more often than the controls. Imaging The lobule VI of the right cerebellum was more activated in the healthy controls relative to the PD patients during successful trials. Also, successful trial-by-trial adjustments were associated with more pronounced activation in the right putamen and lobule VI for the healthy controls relative to the PD patients. PD subjects and healthy controls used identical functional circuits to maintain the successful outcome in predictive motor timing behavior, however the strength of effective connectivity differed between these two groups. Conclusions The cerebellum plays an essential role in integrating incoming visual information with motor output when making predictions about upcoming actions. Both the cerebellum and the basal ganglia are necessary for the predictive motor timing in general, with the cerebellum being associated with the postponement of the action until the right moment, and with both the cerebellum and the basal ganglia needed for successful adaptation in the task from one trial to the next. Future studies of the exact roles of subcortical structures in movement disorders is the challenge for the researchers. This work was supported by the project “CEITEC – Central European Institute of Technology” (CZ.1.05/1.1.00/02.0068) from the European Regional Development Fund and by a research project of the Czech Ministry of Health Foundation (2010–2015) NT/13437.