Interpreting the Mismatch Negativity

Abstract

The widely accepted “memory-mismatch” interpretation of the mismatch negativity (MMN) event-related brain potential (ERP) suggests that an MMN is elicited when an acoustic event deviates from a memory record describing the immediate history of the sound sequence. The first variant of the memory-mismatch theory suggested that the memory underlying MMN generation was a strong auditory sensory memory trace, which encoded the repetitive standard sound. This “trace-mismatch” explanation of MMN has been primarily based on results obtained in the auditory oddball paradigm. However, in recent years, MMN has been observed in stimulus paradigms containing no frequently repeating sound. We now suggest a different variant of the memory-mismatch interpretation of MMN in order to provide a unified explanation of all MMN phenomena. The regularity-violation explanation of MMN assumes that the memory records retaining the history of auditory stimulation are regularity representations. These representations encode rules extracted from the regular intersound relationships, which are mapped to the concrete sound sequence by finely detailed auditory sensory information. Auditory events are compared with temporally aligned predictions drawn from the regularity representations (predictive models) and the observable MMN response reflects a process updating the representations of those detected regularities whose prediction was mismatched by the acoustic input. It is further suggested that the auditory deviance detection system serves to organize sound in the brain: The predictive models maintained by the MMN-generating process provide the basis of temporal grouping, a crucial step in the formation of auditory objects.

What controls gain in gain control? Mismatch negativity (MMN), priors and system biases

“…Although MMN latency (timeto-peak or time-to-onset) can be very informative (Näätänen et al 1978, Schröger and Winkler 1995, Richter et al 2009, it is the MMN amplitude that is generally the main quantifier of interest, whether comparing groups or experimental conditions. MMN amplitude can be construed as an index of the amount of surprise generated by the stimulus based on two main factors: 1) how far the sound falls from predictions reflecting the auditory system's assessment of the most likely continuations of the sound sequence; and 2) the system's confidence in the violated prediction (Winkler, 2007(Winkler, , 2010. Friston (2005) proposed that the MMN process is a basic exemplar of a broader principle of brain function -that prediction facilitates the reduction of entropy (free-energy), which in turn optimises the distribution of limited resources.…”

“…MMN indicates that an auditory input differs from predicted causes and signals the need for two related actions: firstly, the model has proven inaccurate and therefore requires updating (Winkler et al 1996;Winkler 2007), and second, the environment has changed in some way that might require a change in ongoing behaviour (Näätänen 1990;Schröger 1997;Näätänen et al 2011). The former action is indicated by research demonstrating that activity contributing to MMN is dependent on what model(s) the auditory system possesses at the time the deviant is encountered as opposed to the characteristics of the deviant itself (see Winkler et al 1996;Winkler and Czigler, 1998).…”

“…The influence a prediction model has over responsiveness is also a function of the degree to which it has demonstrated accuracy and been reinforced (Winkler 2007;2010). Each time a sound conforms to the next state predicted by the model, confidence in the model is increased.…”

“…By learning the pattern, the probable characteristics of future states can be extrapolated. Learning creates a "prediction model", which is expressed in altered responsiveness to new sounds as a function of past exposure (Winkler et al 1996;Winkler 2007;2010). MMN reflects the outcome of a process that compares current sensory input with expected sensory activation based on the prediction model (Winkler et al 1996).…”

Sensory ERP effects in auditory distraction: did we miss the main event?

“…Following the deviance-onset, processing at the sensory filter is reflected by frontal and central negative differences between 100-200 ms, a superposition of an N1-effect (Näätänen & Picton, 1987), mismatch negativity (Näätänen, Gaillard & Mäntysalo, 1978, for a recent summary see Winkler, 2007), and possibly N2(b) (Näätänen, Simson, & Loveless, 1982;Ritter et al, 1992). The allocation of attention at the second stage is reflected by the P3a peaking fronto-centrally around 300 ms (Friedman, Cycowicz, & Gaeta, 2001), and re-orientation at the third stage is reflected by the so-called reorienting negativity (RON, Schröger & Wolff, 1998a) observable fronto-centrally in the 400-600 ms interval.…”