The mismatch negativity as an index of diﬀerent forms of memory in audition
The mismatch negativity (MMN) (illustrated in Figure 15.1) is an electromagnetic response to a discriminable change (“deviant”) in any repetitive aspect (“standard”) of auditory stimulation (Näätänen, Gaillard, & Mäntysalo, 1978; for reviews, see Näätänen, 2001; Näätänen & Winkler, 1999; Näätänen, Paavilainen, Rinne, & Alho, 2007). The MMN is initiated by an auditory change-detection process in which a diﬀerence is found between the deviant auditory event and the sensory-memory representation of the repetitive aspects of the preceding auditory stimulation. The MMN therefore provides an objective index of sound-discrimination accuracy (Lang et al., 1990; for a review, see Näätänen & Alho, 1997), and it is the only such index. This change-detection process occurs pre-perceptually in the auditory cortices, generating the auditory-cortex subcomponent of the MMN and triggering frontal-cortex processes that, in turn, generate the frontal subcomponent of the MMN and initiate an involuntary attention switch to auditory change (Giard, Perrin, Pernier, & Bouchet, 1990; Näätänen, 1990; Rinne, Alho, Ilmoniemi, Virtanen, & Näätänen, 2000). Consequently, the MMN generation does not result from the aﬀerent processes elicited by the deviant stimuli or events – that is, separate, memory-related neuronal activity is involved rather than just the activation of new (or fresh) aﬀerent elements, those activated by the deviants but not by the standards (for a review, see Näätänen, Jacobsen, & Winkler, 2005).