Ferdinando Rossi Lecture: the Cerebellar Cognitive Affective Syndrome-Implications and Future Directions.

The notion that the cerebellum is devoted exclusively to motor control has been replaced by a more sophisticated understanding of its role in neurological function, one that includes cognition and emotion. Early clinical reports, as well as physiological and behavioral studies in animal models, raised the possibility of a nonmotor role for the cerebellum. Anatomical studies demonstrate cerebellar connectivity with the distributed neural circuits linked with autonomic, sensorimotor, vestibular, associative and limbic/paralimbic brain areas. Identification of the cerebellar cognitive affective syndrome in adults and children underscored the clinical relevance of the role of the cerebellum in cognition and emotion. It opened new avenues of investigation into higher order deficits that accompany the ataxias and other cerebellar diseases, as well as the contribution of cerebellar dysfunction to neuropsychiatric and neurocognitive disorders. Brain imaging studies demonstrate the complexity of cerebellar functional topography, revealing a double representation of the sensorimotor cerebellum in the anterior lobe and lobule VIII and a triple cognitive representation in the cerebellar posterior lobe, as well as representation in the cerebellum of the intrinsic connectivity networks identified in the cerebral hemispheres. This paradigm shift in thinking about the cerebellum has been advanced by the theories of dysmetria of thought and the universal cerebellar transform, harmonizing the dual anatomic realities of homogeneously repeating cerebellar cortical microcircuitry set against the heterogeneous and topographically arranged cerebellar connections with extracerebellar structures. This new appreciation of the cerebellar incorporation into circuits that subserve cognition and emotion enables deeper understanding and improved care of our patients with cerebellar ataxias and novel cerebellar-based approaches to therapy in neuropsychiatry.