Cerebellar-cortical interactions in health, aging and disease.

We address interactions between cerebellum and cerebrum in normal healthy participants using a series of theory-driven behavioural tests of motor performance and learning, as well as functional imaging and dual-site transcranial magnetic stimulation to separately and simultaneously perturb cerebellar and cortical function. We aim to discriminate between two hypothetical cerebellar functions, testing their interaction with motor and associative cortical areas. To study changing cerebello-cereb ral relations, short time-scale changes in connectivity will be explored with analyses of motor learning, and relations between resting activation, prior learning and motor consolidation. Long-term change will be monitored by structural and functional imaging in cerebellar patients with chronic lesions or degeneration. Functional activation and functional connectivity analyses will document compensatory change following cerebellar damage. Age-related changes in cerebello-cerebral interactions wi ll be studied using motor and cognitive tests combined with functional connectivity analysis. To determine role of the cerebellum in higher motor and cognitive tasks, we will test cerebellar patients in tasks ranging from simple movement to non-verbal working memory, and associate performance with cerebellar lesion and cortical compensation. This work is critical for better understanding of the role of the cerebellum and how its cerebello-cerebral interactions change with learning, with di sease and age.