Fig. 2.

EEG responses to novel sounds with and without intervening standard stimuli. (Upper Left) A schematic illustration of the stimulus paradigm. (Upper Right) Mean (±SEM) novel sound response latencies and amplitudes in the “novel sounds with standards” and “novel sounds without standards” conditions. (Lower) Grand-averaged (n = 7) novel sound responses in the novel sounds with standards and novel sounds without standards conditions are shown at a frontal (Fz) electrode position. The convergence of response waveforms with the large (four octave) physical difference between the novel sounds and the intervening standard stimuli suggests that the MMN arises because of selective adaptation of the N1 response by preceding standard stimuli, rather than being generated by distinct neural populations.