[Mismatch negativity: contribution of difference in refractoriness of stimulus-specific neuronal populations]

Mismatch negativity (MMN) is a component of auditory evednt-relate brain potential (ERP) relate to any occasional change in auditory stimulation irrespective of subject's attention. It is believed to reflect an automatic response of specialized change-detector based on comparison of incoming stimulus with memory trace of preceding stimulation. But there is an alternative point of view that MMN might simply arise from difference in neuronal refractoriness. Existence of genuine MMN was proved but the issue of refractoriness contribution still remains open. In this study, we used experimental design allowing separation of the hypothetical MMN sources. Significant refractoriness-related contribution to the traditional MMN has been shown. This contribution decrease along with deviant occurrence probability increase becoming negligible by 15 % probability. We suggest that either refractoriness controlling experimental design or safe deviant probability is to be used to obtain traditionally interpreted MMN.