Abstract
The connections between the cerebellum and basal ganglia were assumed to occur at the level of neocortex. However evidences from animal data have challenged this old perspective showing extensive subcortical pathways linking the cerebellum with the basal ganglia. Here we tested the hypothesis if these connections also exist between the cerebellum and basal ganglia in the human brain by using diffusion magnetic resonance imaging and tractography. Fifteen healthy subjects were analyzed by using constrained spherical deconvolution technique obtained with a 3T magnetic resonance imaging scanner. We found extensive connections running between the subthalamic nucleus and cerebellar cortex and, as novel result, we demonstrated a direct route linking the dentate nucleus to the internal globus pallidus as well as to the substantia nigra. These findings may open a new scenario on the interpretation of basal ganglia disorders.
Highlights
The basal ganglia are thought to play a role in the selection and inhibition of motor commands, while the cerebellum plays a role in tuning and reshaping ongoing movement
Diffusion-based tractography is a method analyzing the preferential water diffusivity directionality along white matter bundles, calculating the highest mathematical probability that water diffuses in a given direction
Tractography is not sufficient to demonstrate the existence of a specific pathway, if used alone
Summary
The basal ganglia are thought to play a role in the selection and inhibition of motor commands, while the cerebellum plays a role in tuning and reshaping ongoing movement. The lateral deep cerebellar nucleus was found to project to the dorsolateral striatum via the central lateral nucleus of the thalamus (Ichinohe et al, 2000) It was shown in Direct Subcortical Cerebello-Basal Ganglia Connections primates, that the dentate and interpositus deep cerebellar nuclei send projections via di-synaptic or tri-synaptic pathways to the putamen or external segment of the globus pallidus (GP), with Th as an intermediate relay station (McFarland and Haber, 2000; Hoshi et al, 2005). Anatomical studies in rats and cats have suggested the existence of a pathway starting from deep cerebellar nuclei and reaching nigro-striatal dopamine neurons (Snider et al, 1976) All these connections were found to exit from cerebellum (efferent projections), an afferent pathway connecting basal ganglia and cerebellum was described (Bostan et al, 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
