Background: Mismatch negativity (MMN) of event-related potentials (ERPs) is useful in understanding the brain function, especially auditory perception and immediate memory. Auditory MMN (a-MMN) is characterized by several features. Visual analogue of MNN (v-MMN) has been reported, however, it is unknown about its properties. Objective: The aim of this study was to delineate functional characterization of v-MMN. Methods: Twelve normal adults were instructed to listen to a story and to also pay attention to a visual target. Windmill patterns consisting of a standard (S), a deviant (D), and a target (T) stimulus whose ratio was 8:1:1 were presented randomly. The difference of stimuli was the number of vanes. To ensure endogeneity, S and D stimuli were alternated. To vary deviancy, deviants were changed by modulating the number of vanes. To examine the effect of T stimulus on changes in detection, two target conditions were used. To elucidate sensory memory, additional experiments were performed in eleven subjects. Train bursts that consisted of one D and eight S stimuli were presented repeatedly with changing either inter-trains interval or sequence. Deviant-related component (DRC) was obtained by subtracting ERPs to the S from that to the D stimulus. Results: Subjects'' attention was directed to auditory context and the T stimulus. DRC appeared 150-300 ms after the stimulus onset and consisted of an early (DRN1) and a late (DRN2) component. Deviancy significantly influenced the latency of DRN2, while the change of the T stimulus affected latencies of both DRN1 and DRN2.
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