Interactive roles of the cerebellum and striatum in sub-second and supra-second timing: Support for an initiation, continuation, adjustment, and termination (ICAT) model of temporal processing.

The contributions of cortico-cerebellar and cortico-striatal circuits to timing and time perception have often been a point of contention. In this review we propose that the cerebellum principally functions to reduce variability, through the detection of stimulus onsets and the sub-division of longer durations, thus contributing to both sub-second and supra-second timing. This sensitivity of the cerebellum to stimulus dynamics and subsequent integration with motor control allows it to accurately measure intervals within a range of 100-2000ms. For intervals in the supra-second range (e.g., >2000ms), we propose that cerebellar output signals from the dentate nucleus pass through thalamic connections to the striatum, where cortico-thalamic-striatal circuits supporting higher-level cognitive functions take over. Moreover, the importance of intrinsic circuit dynamics as well as behavioral, neuroimaging, and lesion studies of the cerebellum and striatum are discussed in terms of a framework positing initiation, continuation, adjustment, and termination phases of temporal processing.