ERPs and deviance detection: visual mismatch negativity to repeated visual stimuli.

Previous studies showed a visual analogue of the mismatch negativity (MMN) event-related potential (ERP), which is elicited by violating some sensory regularity. Separating physical change from violating a regularity, here we show that the visual MMN (vMMN) is elicited by regularity violations that do not involve physical stimulus change. Adult participants were presented with a series of red-black and green-black checkerboard patterns delivered regularly in an RRGGRRGG ... order. Infrequently (p=0.1) this regularity was broken by repeating a stimulus one additional time (e.g. RRGGRRR). ERPs elicited by irregular stimulus repetitions were negatively displaced compared to those elicited both by regular repetition and regular change in two latency ranges: 100-140 ms and 220-260 ms. Whereas the first of these two negative ERP differences appears to be sensitive to stimulus repetition per se, the second difference can be identified as a vMMN response to violating the sequential regularity. Thus, similarly to its auditory counterpart, vMMN reflects deviance-(regularity-violation) rather than change-detection processes.