Imagery and motor learning: a special issue on the neurocognitive mechanisms of imagery and imagery practice of motor actions.

Human beings are able to imagine actions with the aim to change movement coordination and to learn particular movements. Meta-analyses to date have shown that when individuals systematically engage in imagery of a motor action without overt behavior this can improve motor performance and facilitate motor learning. Despite a considerable body of research in neuroscience, psychology, and sport science, however, there is at present no consensus on the neurocognitive mechanisms of imagery, and the mechanisms that lead to learning via imagined action are still being debated. In particular, the differences between imagined and overt action, and respective learning effects, remain to be fully explained. The present collection of manuscripts is a result of compiling both theoretical advances in the field of motor control and motor learning and those in imagery research to better understand imagery and learning. It is structured alongside five position papers from leading experts in the field, each of which is followed by a series of short commentaries written by experts from various disciplines. This collection demonstrates (a) that conceptualizations of imagery are manifold, vary highly and depend on the perspective chosen, (b) that existing approaches to the neurocognitive mechanisms of imagery and imagery practice of motor actions draw on distinct motor control and learning perspectives, (c) that perspectives from the wider fields of motor control and learning stimulate new approaches to explain imagery and imagery practice, (d) and that future research is needed to investigate and compare different perspectives and conceptualizations of the neurocognitive mechanisms of imagery and imagery practice of motor actions.

Stimulus specificity in combined action observation and motor imagery of typing.

Combined action observation and motor imagery (AO + MI) can improve movement execution (ME) in healthy adults and certain patient populations. However, it is unclear how the specificity of the observation component during AO + MI influences ME. As generalised observation could result in more flexible AO + MI rehabilitation programmes, this study investigated whether observing typing of target words (specific condition) or non-matching words (general condition) during AO + MI would have different effects on keyboard typing in healthy young adults. In Experiment 1, 51 students imagined typing a target word while watching typing videos that were either specific to the target word or general. There were no differences in typing execution between AO + MI conditions, though participants typed more slowly after both AO + MI conditions compared with no observation or imagery. Experiment 2 repeated Experiment 1 in 20 students, but with a faster stimulus speed in the AO + MI conditions and increased cognitive difficulty in the control condition. The results showed that the slowed typing after AO + MI was likely due to a strong influence of task-switching between imagery and execution, as well as an automatic imitation effect. Both experiments demonstrate that general and specific AO + MI comparably affect ME. In addition, slower ME following both AO + MI and a challenging cognitive task provides support for the motor-cognitive model of MI.