Interval timers and coupled oscillators both mediate the effect of temporally structured cueing

When observers are presented with targets in the context of temporal structure, performance is modulated by that structure. Interval timing mechanisms and coupled oscillators are two popular classes of model that attempt to explain how temporal structure modulates attention and motor performance to bring about the behavioral costs and benefits of temporal structure. In this experiment, participants made speeded choice reactions to targets following a series of visual warning stimuli. The warning stimuli afforded prediction of target onset time. Brain activity related to temporally focused attention and motor preparation was measured using magnetoencephalography. Parietal, cerebellar, and somatomotor activity was found to be associated with response latency and the performance benefit of the cued relative to uncued targets. Parietal activity was consistent with an interval timing mechanism, while somatomotor activity was more consistent with a coupled oscillator mechanism. Cerebellar activity had features consistent with both mechanisms. To our knowledge, this is the first evidence that both processes occur simultaneously. (C) 2008 Elsevier Inc. All rights reserved.