Perception of Short, but Not Long, Time Intervals is Modality Specific: EEG Evidence Using Vibrotactile Stimuli

A longstanding debate in cognitive neuroscience questions whether temporal processing is modality-specific or governed by a "central clock" mechanism. We propose that this debate stems from neglecting the duration of the intervals processed, as studies supporting modality-specific models of time perception often focus on below 1.2-s intervals. To address this, we examined the neuronal dynamics underlying the perception of time intervals shorter and longer than 1.2-s using vibrotactile stimuli. Twenty participants underwent electroencephalogram recordings during a passive tactile oddball paradigm. We compared brain responses to standard and deviant intervals, with deviants occurring either earlier or later than the standard in both below and above 1.2-s conditions. Event-related potentials revealed distinct deviance-related components: a P250 for deviance detection of short deviants and an N400 long deviants. Generators lied in a modality-specific network for short intervals, while long intervals activated a broader, higher-level network. We found no evidence of the contingent negative variation in the tactile modality, questioning its role as a universal marker of temporal accumulation. Our findings suggest that short intervals involve modality-specific circuits, while longer intervals engage distributed networks, shedding light on whether temporal processing is centralized or distributed.