Time perception and temporal processing levels of the brain.

A classification is presented to structure divergent empirical findings on temporal mechanisms of the brain. Proceeding from our time experiences of simultaneity, nonsimultaneity, temporal order, duration, and the subjective present, a classification of thresholds is established that marks distinct processes involved in time perception and the temporal control of movements. On the basis of this classification, evidence has been collected that suggests that perception and action share common timing mechanisms. Furthermore, brain structures involved in temporal aspects of behavior on different time scales have been identified--namely, the cerebellum, the basal ganglia, and circumscribed cortical regions. Another question under debate concerns the representational mode in which time is represented in the brain; models suggest neuronal oscillations or interval-based mechanisms.