Sound energy and the magnitude of change: effects on mismatch negativity

The mismatch negativity (MMN) of event-related potential generally increases in amplitude, as a function of magnitude of change. This study examined whether this relation holds true for intensity decrement, in which the stimulus energy that conveys the change falls in inverse proportion to magnitude of change. The MMN was recorded from healthy young adults for intensity decrements of 10, 20, 30, 40, and 50 dB. As the change increased, the MMN amplitude also increased first and thereafter diminished; thus, an inverted U-shaped relation was found between the MMN amplitude and the magnitude of change. These results, therefore, suggest a possible interplay between the energy of deviant stimulus and magnitude of change in the MMN elicitation.