Figure 1.

Trial design and behavioral results. A, Trial of behavioral Experiment 1 that contains a long oddball and target (long oddball-target trial). When present in a long oddball trial, the target could be at lag 2 (depicted) or lag 13 from oddball offset. B, Trial of fMRI Experiment 1 that contains two short oddballs separated by an 8 s interval (dual-short oddball trial). C, Results of behavioral Experiment 1 (distinct oddballs). Each graph shows target identification performance in trials that contain no oddball and in trials in which the target appeared at lag 2 or 13 following the oddball presentations. D, Results of behavioral Experiment 2 (repeated oddball). Error bars represent SEM.