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 t he visual held, and to frequent standard and infrequent deviant stimuli pre sented outside the focus of attention, in the peripheral held. Deviants evo ked a more negative potential than standards 250-400 ms after the stimulus. The negativity, distributed over supplementary visual areas of occipital a nd posterior temporal cortex, was associated with the rarity of the deviant s and not the physical features which distinguished them from standards. Th is negativity shares a number of characteristics with auditory MMN. NeuroRe port 10:3363-3367 (C) 1999 Lippincott Williams & Wilkins.