Electric and Magnetic Brain Responses Evoked by Deviant Tones in Melodies

The perception of deviant tones in an otherwise stereotyped sequence of auditory stimuli creates a characteristic mismatch activity (MMA) in the auditory cortex, which typically has a latency of about 150 ms and which can be recorded with EEG or MEG (mismatch negativity, MMN or mismatch field, MMF) [1]. MMA is generally viewed as reflecting the “hits” of an ever ongoing search for novel events based on the comparison of current events with a memory trace of the preceding ones, that is, on short term memory [2]. Alternatively, however, one could conceive of a more generalized mechanism based on the brain’s ability to compare actual with predicted events. To pursue this question we investigated whether detection of “wrong” tones in pieces of classical music would also evoke MMA.