Mismatch negativity is unaffected by top-down predictive information

The mismatch negativity (MMN) event-related brain potential is assumed to r eflect a stimulus-driven change detection process. We examined whether MMN is sensitive to volitional control by testing whether MMN is affected by th e subject's foreknowledge of the sound changes. Subjects were instructed to produce a sequence of button presses by pressing one button frequently and another infrequently. In the predictable condition, the frequently pressed button triggered the standard tone. the other button the deviant tone. In the unpredictable condition, each button press triggered the next tone of a prearranged standard/deviant sequence. No difference was found in the MMN amplitude. latency, or scalp distribution between the predictable and unpre dictable conditions. This suggests that there is no direct top-down control over the MMN-generating process. NeuroReport 12:2209-2213 (C) 2001 Lippinc ott Williams & Wilkins.