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Abstract: We used high-density event-related potentials (ERP) in a modified flanker paradigm to study the role of anticipated action consequences in action planning and the role of anticipation in the perception of action consequences. Prior to the experiment, participants were trained to classify target letters in a four-alternative forced-choice task; another letter was presented as an effect following each response. After participants had thus acquired the response–effect contingencies, in the experiment effect letters were presented as flankers to target letters. Effect-compatible flankers were letters that were learned as effects of the correct response to the target; effect-incompatible ones were learned as effects of other responses; neutral flankers were never presented as action effects. To help distinguish early and late effects of flankers on target processing, flankers were presented either simultaneously with the target or after a delay. We found that effect-incompatible flankers resulted in longer, than other flankers, time between the onset of the response-locked lateralized readiness potential and the response, indicating extended motor processing. ERP evoked by the effect-incompatible flankers differed from those evoked by other flankers in early perceptual component P1 and in later frontal component P2 reflecting stimulus evaluation and conflict detection. These results show that anticipating action consequences involves brain systems ranging from perceptual to executive; anticipated action effects constitute a link between perception and action. [Copyright &y& Elsevier]

Abstract: Visual integration between target and irrelevant features leads to effects of irrelevant feature congruency (Stroop) or variation (Garner) on target classification performance. Presenting closed geometrical shapes as stimuli, we obtained Stroop and Garner effects of one part of their contour on another, in response times and error rates. The correlates of these effects in brain activity were observed in event-related potentials (ERP). Stroop effects occurred in ERP amplitude of the N1 and N2 components, starting about 170 ms after stimulus onset; Garner effects occurred in amplitude of the rising part of the P3 component, starting about 330 ms after stimulus onset. A subsequent point-wise analysis of Stroop and Garner effects in ERP showed that they belong to different, cascaded processing stages. The difference in time course between Stroop and Garner effects in ERP is in accordance with the view that both are produced by different mechanisms, the former sensitive to interference within presentations and the latter sensitive to interference between presentations. The brief interval of 330–370 ms after stimulus onset when these two mechanisms overlap may correspond to the central processing bottleneck, responsible for the combinations of Stroop and Garner effects generally found in response times. [Copyright &y& Elsevier]