The influence of motor imagery on the learning of a sequential motor skill

Motor imagery has been argued to affect the acquisition of motor skills and to improve performance in sports disciplines and rehabilitation. The present study examined whether motor imagery induces the learning of a sequential motor skill by employing a modified discrete sequence production (DSP) task: the Go/NoGo DSP task. In our task, sequences of five stimuli signaling a specific response sequence were presented. After an informative cue, the cued response sequence had either to be executed, to be imagined or to be withheld. To establish an effect of motor learning, the experiment was divided into a practice phase, and a final test phase. In the latter phase we compared mean response times and accuracy during the execution of new sequences, old imagined sequences and old executed sequences. The electroencephalogram (EEG) was measured to compare activity between motor imagery, motor execution, and motor inhibition in the practice phase. Event-related potentials (ERPs) and event-related lateralizations (ERLs) in the practice phase showed strong similarities on trials requiring motor imagery and motor execution, while a major difference was found on trials for which the response sequence should be withheld. Behavioral results in the test phase revealed that the accuracy for imagined sequences in the practice phase was improved relative to new sequences, which confirms the idea that motor imagery induces motor skill learning.