Introduction

Contemporary investigations provide substantial clinical and experimental support for the hypothesis generated in the early part of the twentieth century that the cerebellum participates in a multitude of nervous system functions beyond that of motor control. Executive functions such as strategy formation, self-monitoring, reasoning, and working memory; visual–spatial learning and analysis; and linguistic processing, among other cognitive paradigms, have all been shown to require a cerebellar contribution both in normal subjects and in patients with acquired cerebellar lesions. The role of the cerebellum in the modulation of emotion also appears to be critically important in both health and disease states. The focus of this chapter, therefore, is directed toward the cerebellar contribution to behaviors associated with the experience and expression of emotion. It summarizes anatomic investigations demonstrating substrates that could sustain a cerebellar contribution to nonmotor as well as motor behaviors, and describes contemporary clinical studies that report changes in behavior, personality, and affect following lesions of the cerebellum. It includes data from morphologic and functional neuroimaging experiments that support a wider role of the cerebellum in nervous system function, and specifically that suggest an important contribution of the cerebellum to the regulation of affect and to psychosis. The chapter concludes with an examination of the dysmetria of thought hypothesis, and discusses how this theory harmonizes with models of cerebellar function proposed by other contemporary theorists.