Pre-conference workshop: Methodological aspects of MMN research
Tuesday, Sep 8, 2015
The mechanisms and meaning of the mismatch negativity
1New York, United States
The underlying neural mechanisms and meaning of the mismatch negativity (MMN) continue to be debated. Two dominant explanations for the MMN have been proposed. According to the “neural adaptation” hypothesis, repeated presentation of ‘standard’ sounds results in adapted (i.e., attenuated) responses of feature-selective neurons in auditory cortex. Rare ‘deviant’ sounds activate neurons that are less adapted than those stimulated by the frequent standard sounds, and thus elicit a larger ‘obligatory’ event-related response (e.g., N1), which yields the MMN upon subtracting the response to standards from the response to deviants. In contrast, according to the “sensory memory” hypothesis (and the related “predictive coding” interpretation), the MMN is a ‘novel’ (non-obligatory) response component that reflects the deviant’s violation of a neural ‘memory trace’ or prediction generated by the regularity of the preceding standards. In this talk I consider evidence supporting the adaptation and sensory memory/predictive coding models of the MMN. I also present neurophysiological data obtained from monkey auditory cortex, which have potential implications for the debate between proponents of the two competing models and for the interpretation of non-invasively recorded event-related responses more generally. I conclude with an assessment of where the debate currently stands and with remarks on how further progress can be made with regard to clarifying the mechanisms and meaning of the MMN.