Subjective present: a window of temporal integration indexed by mismatch negativity.

It has been proposed that temporal perception is implemented in a "time window" of approximately 3 s which we experience as "present". Using mismatch negativity (MMN), we tested the hypothesis whether a time window of 3 s is selective for pre-attentively detecting the violation of regularity in a stimulus sequence by employing different interstimulus intervals. Our results showed that in frontal midline areas, the amplitudes of MMN were significantly larger for the shorter interstimulus intervals up to 3 s than for the longer ones. In lateralized frontal areas, male subjects seemed to have a stronger effect in the temporal modulation of the MMN, which might deserve further investigation. We conclude that a time window of 3 s is selective for neuronal mechanisms to process deviant stimuli and that information processing is temporally segmented, creating a "subjective present" in discrete sequential steps.