title: Cognitive and motor loops of the human cerebro-cerebellar system.
abstract: We applied fMRI and diffusion-weighted MRI to study the segregation of cognitive and motor functions in the human cerebro-cerebellar system. Our fMRI results show that a load increase in a nonverbal auditory working memory task is associated with enhanced brain activity in the parietal, dorsal premotor, and lateral prefrontal cortices and in lobules VII-VIII of the posterior cerebellum, whereas a sensory-motor control task activated the motor/somatosensory, medial prefrontal, and posterior cingulate cortices and lobules V/VI of the anterior cerebellum. The load-dependent activity in the crus I/II had a specific relationship with cognitive performance: This activity correlated negatively with load-dependent increase in RTs. This correlation between brain activity and RTs was not observed in the sensory-motor task in the activated cerebellar regions. Furthermore, probabilistic tractography analysis of the diffusion-weighted MRI data suggests that the tracts between the cerebral and the cerebellar areas exhibiting cognitive load-dependent and sensory-motor activity are mainly projected via separated pontine (feed-forward tracts) and thalamic (feedback tracts) nuclei. The tractography results also indicate that the crus I/II in the posterior cerebellum is linked with the lateral prefrontal areas activated by cognitive load increase, whereas the anterior cerebellar lobe is not. The current results support the view that cognitive and motor functions are segregated in the cerebellum. On the basis of these results and theories of the function of the cerebellum, we suggest that the posterior cerebellar activity during a demanding cognitive task is involved with optimization of the response speed.
authors.affiliation: Department of Psychology, University of Helsinki, Finland. juha.salmi@helsinki.fi
authors.forename: Juha
authors.initials: J
authors.lastname: Salmi
authors.forename: Karen Johanne
authors.initials: KJ
authors.lastname: Pallesen
authors.forename: Tuomas
authors.initials: T
authors.lastname: Neuvonen
authors.forename: Elvira
authors.initials: E
authors.lastname: Brattico
authors.forename: Antti
authors.initials: A
authors.lastname: Korvenoja
authors.forename: Oili
authors.initials: O
authors.lastname: Salonen
authors.forename: Synnöve
authors.initials: S
authors.lastname: Carlson
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001931:Brain Mapping; D002531:Cerebellum / Q000098:blood supply / Q000502:physiology*; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009068:Movement / Q000502:physiology*; D009434:Neural Pathways / Q000098:blood supply / Q000502:physiology; D010100:Oxygen / Q000097:blood; D011930:Reaction Time / Q000502:physiology; D013223:Statistics as Topic; D055815:Young Adult
chemical_list: D010100:Oxygen