Cerebellar contributions to motor control and language comprehension: searching for common computational principles

Abstract

The past 25 years have seen the functional domain of the cerebellum extend beyond the realm of motor control, with considerable discussion of how this subcortical structure contributes to cognitive domains including attention, memory, and language. Drawing on evidence from neuroanatomy, physiology, neuropsychology, and computational work, sophisticated models have been developed to describe cerebellar function in sensorimotor control and learning. In contrast, mechanistic accounts of how the cerebellum contributes to cognition have remained elusive. Inspired by the homogeneous cerebellar microanatomy and a desire for parsimony, many researchers have sought to extend mechanistic ideas from motor control to cognition. One influential hypothesis centers on the idea that the cerebellum implements internal models, representations of the context-specific dynamics of an agent’s interactions with the environment, enabling predictive control. We briefly review cerebellar anatomy and physiology, to review the internal model hypothesis as applied in the motor domain, before turning to extensions of these ideas in the linguistic domain, focusing on speech perception and semantic processing. While recent findings are consistent with this computational generalization, they also raise challenging questions regarding the nature of cerebellar learning, and may thus inspire revisions of our views on the role of the cerebellum in sensorimotor control.

Cerebellar Contributions to Language in Typical and Atypical Development: A Review

“…Moberget and Ivry (2016) also argue that the cerebellum contributes to the process of adaptation during speech perception and language comprehension. For example, the listener must adapt online to cues from co-articulation, accent, and other paralinguistic cues such as prosody, visual gestures of speech movements, lexical information, and sentential and narrative-level semantic information.…”

“…The most influential class of models of cerebellar function, collectively called “internal models”, proposes that the cerebellum is involved in generating predictive, feed-forward “internal” models of potential consequences of enacted behaviors. Specifically, it is proposed that the cerebellum generates representations of the context-specific dynamics of the organism’s interactions with the environment (Moberget & Ivry, 2016). According to Ito (1993; 2008), the organization of the cerebellum supports this process by establishing individuated microcircuits that make feed-forward predictions about the next sensorimotor state of the organism.…”

“…In this respect, the internal models hypothesis has provided a rich framework for understanding the cerebellum’s contribution to motor function, and has become the dominant model in this domain (Ebner 2013). Moberget and Ivry (2016) have recently applied this theory to language, and have proposed that internal models contribute to three components important to language processing: 1) timing; 2) adaptation; 3) prediction.…”

“…Finally, Moberget and Ivry (2016) suggested that the cerebellum might contribute to predictive processing during language comprehension in situations that involve temporal or sequential associations. There is emerging evidence in support of this hypothesis.…”

“…Thus, researchers must become comfortable with the neural and computational models established in animal research, and apply those theories to their studies on humans. Recent papers (e.g., Moberget & Ivry, 2016) provide excellent examples of how work in understanding the cerebellum’s contribution to language must be conducted at multiple levels of analysis. A comprehensive theoretical framework, such as the internal model theory, is also necessary to focus these investigations.…”