Abstract
The response-priming paradigmis frequentlyemployed to studymotor control bymeans of behavioural aswell as psychophysiological methods. In this paradigm, response performance is studied under various preparation conditions, but in all cases participants are generally primed for action. This setting neglects an essential ability of the motor system in everyday situations, i.e. the efficient execution of a movement with and without warning. In this context the present experiment assessed the behavioural effects of a modified response-priming paradigm, in which participants were asked to execute movements when primed for action, and when the prime predicted that no response would be required. Thirty volunteersparticipated the experiment, which tested whether the insertion of no-response trials would affect the validity effect, and assessed the differences between invalid trials and reactions performed subsequent to no-response primes. The data showed that the validity effect is not modulated by the added no-response condition, which suggests that movement preparation mechanisms can be studied with this particular task. In addition, responses in invalid trials were substantially different from responses executed after no-response primes. These results are interpreted in relation to psychophysiological evidence on advance movement preparation. It is proposed that the performance differences between response- and no-response priming conditions may be due to different preactivations of motor regions evoked by the prime stimuli, a hypothesis to be addressed with psychophysiological measures in the future. Keywords: Validity effects; Motor control; Advance movement preparation