Category effects: Is top-down control alone sufficient to elicit the mismatch negativity (MMN) component?

This study investigated whether the mismatch negativity (MMN) event-related brain potential (ERP) could be evoked by purely top-down, attentional control. An infrequently occurring tone was designated as a target prior to presenting a randomized sequence of five equi-probably occurring tones. MMN elicitation to the tones categorized as " high" , " medium" , or " low" frequency, and designated as the target, would indicate that the change detection process can be driven solely by top-down control. However, MMNs were not elicited by the categorized tones. Only the N2b and P3b attention-driven target detection components were elicited. These results suggest that top-down factors alone cannot generate mismatch negativity. Standard formation by stimulus-driven factors is required.