We examined the neural correlates associated with a short gap between two identical pure tones (within-channel) and between two di¡erent tones (between-channel) in an odd-ball paradigm. Gap durations were selected such that a gap between identical tones was as discriminable as a gap between two di¡erent tones. Spatio-temporal dipole source modeling of electrophysiological data revealed a signi¢cant di¡erence between standard and deviant gap stimuli, with mismatch negativity responses that were comparable in amplitude and latency for within-and betweenchannel conditions.Therefore, the ability to automatically register discontinuity (i.e., gap) within and between channels is comparable despite signi¢cant di¡erences in gap size.The dipole source modeling suggests that both within-and between-gap signals are represented in or near the primary auditory cortex. NeuroReport