Measuring the Genuine Mismatch Negativity in the Auditory Multi-Feature Paradigm.

The mismatch negativity (MMN) is a well-studied event-related potential (ERP) component in the EEG reflecting deviance detection in the auditory modality. It taps into the basic functioning of auditory regularity processing. The auditory multi-feature paradigm is widely used in sensitive and special populations to measure the MMN simultaneously for different sound features in a short amount of time. It is consensus in the field that both adaptation and genuine deviance detection contribute to the "classic" MMN computed as deviant minus standard ERP difference. However, no attempts have yet been made to disentangle adaptation from the "genuine" MMN in the multi-feature paradigm. Here, we propose a cascadic control condition for the auditory multi-feature paradigm that controls for adaptation and physical differences between standard and deviant sounds. Using this new paradigm, we measured the genuine MMN, computed as deviant minus control ERP difference, for frequency, location, intensity, and duration deviants. The genuine MMN amplitudes for frequency and location were found substantially smaller than in traditional paradigms. No genuine intensity MMN and only a later and smaller genuine duration MMN were found. The results suggest stronger contributions of adaptation than in the traditional oddball paradigm. Controlling for adaptation is particularly relevant in research concerning predictive processing and the use of the MMN as a biomarker related to impaired NMDA receptor synaptic transmission as observed in schizophrenia. The presented multi-feature cascadic control condition enables the measurement of the genuine MMN, which presumably reflects higher-order cortical computations, such as predictive processing, still in a short amount of time.