Anticipated action consequences as a nexus between action and perception: evidence from event-related potentials.

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.