Cued Recall of Human Motor Memory

In verbal memory, retrieval cues can facilitate recall of otherwise inaccessible information. Recent work, using passive movements following a motor learning task, suggests that somatic retrieval cues similarly access motor memories. The present study aims to further describe somatic retrieval cues for motor memory and to determine the specificity required for an effective cue. In a visuomotor adaptation paradigm, participants made reaching movements while holding a robotic manipulandum. A visual rotation was gradually imposed, resulting in compensatory movements. Somatic retrieval cues, in the form of passive movements, were then presented. Afterwards, retention of the original learning was evaluated with active movements in the absence of visual feedback. In a first experiment, as in previous work, we found that participants who were given a retrieval cue in the direction of learning were better able to reproduce the learned movement than participants who were given no retrieval cue. A second experiment showed that a retrieval cue only provided this benefit when in the direction of learning, but not when at directions moved to early in learning or beyond the learned direction. We also demonstrated that presenting an otherwise effective retrieval cue in the absence of learning had no effect on active movement. We conclude that as in verbal memory, retrieval cues can facilitate access to motor memories, but only when the cue is sufficiently similar to the learned movement.