The language of the cerebellum

Abstract

Background: During the past three decades neuroanatomical, neuroimaging, and clinical studies have substantially altered the view on the role of the cerebellum as a sole coordinator of sensorimotor function. Currently, the cerebellum is believed to be also crucially involved in cognitive, affective, and behavioural functioning.Aims: This paper aims to summarise a number of critical insights from different research areas (anatomy, functional imaging, clinical practice) that provide evidence for a role of the cerebellum in motor speech and nonmotor language processing.Main contribution: By means of identifying a dense network of crossed reciprocal connections between the cerebellum and the supratentorial association areas, neuroanatomical studies provided a robust basis for the development of new insights in the modulatory role of the cerebellum in neurocognition, including nonmotor language processing. A topological distinction was established between the motor cerebellum, projecting to the cortical motor areas, and the cognitive/affective cerebellum, connected with the cortical and limbic association areas. Neuroimaging studies demonstrated cerebellar involvement in several different language tasks, even after controlling for motor aspects. In addition, several clinical studies identified a variety of nonmotor linguistic deficits after cerebellar damage, implying a prominent role for the cerebellum in these linguistic processes. Functional neuroimaging confirmed the functional impact of cerebellar lesions on remote, structurally intact cortical regions via crossed cerebello-cerebral diaschisis.Conclusion: Evidence from neuroanatomical, neuroimaging, and clinical studies suggests a strongly lateralised involvement of the cerebellum in a broad spectrum of nonmotor language functions through crossed cerebello-cerebral connectivity. It is argued that the cerebellum is involved in language in a similar manner as it is involved in motor functions: through monitoring/coordinating cortical functions.