A synthesis of the role of the cerebellum in cognition

Abstract

Background: Traditional neurological tenets posit that the cerebellum coordinates skilled voluntary movements, and controls motor tone, posture, and gait. However, anatomical, clinical, and neuroimaging studies conducted over the past decades have shown that the cerebellum is implicated in diverse higher cognitive functions, such as language, memory, visuospatial skills, executive functions, thought modulation, and emotional regulation of behaviour.

Address correspondence to: Prof. Dr Philippe F. Paquier, Service de Neurologie, Hôpital Universitaire Erase, 808 route de Lennik, B‐1070 Bruxelles, Belgium. Email: [email protected]

Aims: To provide an introductory overview of the recently acknowledged role of the cerebellum in a number of cognitive processes, with special emphasis on its implication in speech and language functions.

Main Contribution: The role the cerebellum plays in motor speech disorders is not limited to (ataxic) dysarthria, but also encompasses mutism and possibly apraxia of speech. Cerebellar‐induced language impairments may consist of agrammatism and frontal (dynamic) aphasia‐like phenomena, along with semantic retrieval deficits, syntactic comprehension difficulties, and depressed phonological verbal fluency tasks. In addition to speech and language functions, the cerebellum seems also to be implicated in several aspects of memory, such as procedural learning, paired‐associative learning, long‐term memory, and working memory. The cerebellum appears to modulate executive functions, such as planning, set‐shifting, and abstract reasoning as well. Furthermore, it has been shown that the cerebellum intervenes in utilising the precise representation of temporal information not only for motor but also for perceptual tasks. The cerebellum further seems able to optimise the quality of sensory information for coordinating orientation, distribution, and shifting of attentional processes. Visuospatial skills and spatial cognition also appear to depend on cerebellar participation. Finally, a relationship between visuomotor imagery and cerebellar activation in the absence of real movement has been demonstrated.

Conclusions: The role of the cerebellum in the nervous system transcends appreciably the traditional notion of motor control. The cerebellum is also involved in sensory, cognitive, and affective processes, and this in a topographically precise manner. Damage to the cerebello‐cortical loop brings about comportments that resemble those of injury to the cerebral cortical areas subserved by that loop. Rather than generating cognitive processes, the cerebellum is considered to modulate cognitive functions through the feedforward loop of the cortico‐ponto‐cerebellar system and the feedback loop of the cerebello‐thalamo‐cortical pathways. Since the 1980s the concept of cerebellar cognition has evolved from an amusing curiosity to a stimulating new area of neuroscience that opens a multitude of perspectives for future research.

Notes

Address correspondence to: Prof. Dr Philippe F. Paquier, Service de Neurologie, Hôpital Universitaire Erase, 808 route de Lennik, B‐1070 Bruxelles, Belgium. Email: [email protected]

Although these authors admitted the presence of a minute lesion in the right lobulus simplex.