FIGURE 2.

Simulation results. (A) Standard stimuli presented at a fast rate (blue curve) elicit no discernible response, whereas the occasional stimulus omission (red curve) results in a prominent MMN. (B) Occasionally repeating a tone (red) in a sequence of alternating tones (blue) results in an MMN. (C) The blue curve is the response to a sequence xxxxX of five tones presented as a global standard, and the red curve is the response elicited by the same xxxxX as an infrequent global deviant. When the sequence is a global deviant, the ending of the sequence elicits a much stronger response than when it is a global standard. Zero time indicates the onset of the fifth tone. (D) In the classic oddball paradigm, frequency deviants (red) elicit a stronger response than the standards (blue). The response to the deviants is also stronger than the response elicited by the same deviants when these are presented as part of a random sequence of tones, in the so-called multi-standard control condition (black). (E) Standards (blue) and deviants (red) were presented as a series of anisochronous stimuli where the SOI varied randomly.