Mismatch negativity in the visual modality.

In the auditory system, the automatic detection of stimulus change provides a mechanism for switching attention to biologically significant events. It gives rise to the mismatch negativity (MMN) event related potential. It is unclear whether a similar mechanism exists in vision. To investigate this issue, evoked potentials were recorded to target stimuli in the centre of the visual field, and to frequent standard and infrequent deviant stimuli presented outside the focus of attention, in the peripheral field. Deviants evoked a more negative potential than standards 250-400 ms after the stimulus. The negativity, distributed over supplementary visual areas of occipital and posterior temporal cortex, was associated with the rarity of the deviants and not the physical features which distinguished them from standards. This negativity shares a number of characteristics with auditory MMN.