Electrophysiological correlates of temporal generalization: evidence for a two-process model of time perception.

In an event-related potential (ERP) study, brain correlates of temporal processing in the range of milliseconds were investigated by means of a dissociation paradigm. For this purpose, ten male and ten female subjects performed temporal and pitch generalization tasks with uni- and bidimensional stimulus variation. With difficulty held constant for both tasks, a larger frontally distributed negative slow wave was observed for pitch generalization relative to temporal generalization. This ERP pattern was consistent across uni- and bidimensional tasks of the present study but in direct contrast to prior ERP studies on temporal processing. Furthermore, for both uni- and bidimensional temporal tasks, within-task ERP analyses yielded amplitude modulation of centro-parietal P3b and fronto-central P500 as brain correlates of actively processed stimulus duration. Findings were consistent with a two-process model of temporal information processing based on a real-time comparison of the presented stimulus duration against an internal representation of the standard duration.