The evolution of brain activation during temporal processing

Timing is crucial to many aspects of human performance. To better understan d its neural underpinnings, we used event-related fMRI to examine the time course of activation associated with different components of a time percept ion task. We distinguished systems associated with encoding time intervals from those related to comparing intervals and implementing a response. Acti vation in the basal ganglia occurred early, and was uniquely associated wit h encoding time intervals, whereas cerebellar activation unfolded late, sug gesting an involvement in processes other than explicit timing. Early corti cal activation associated with encoding of time intervals was observed in t he right inferior parietal cortex and bilateral premotor cortex, implicatin g these systems in attention and temporary maintenance of intervals. Late a ctivation in the right dorsolateral prefrontal cortex emerged during compar ison of time intervals. Our results illustrate a dynamic network of cortica l-subcortical activation associated with different components of temporal i nformation processing.