Greater neural overlap between motor imagery and working memory than with movement execution: A meta-analytic comparison.

Motor imagery, the mental simulation of movement without physical execution, has traditionally been linked to the neural mechanisms of actual movement, as proposed by Motor Simulation Theory. However, recent frameworks, such as the Motor-Cognitive Model, suggest a closer link between motor imagery and executive functions, particularly working memory. This meta-analytic study quantitatively compared data from 697 neuroimaging studies on motor imagery, movement execution, and working memory. Activation likelihood estimation (ALE) and conjunction analyses revealed that 60% of the volume recruited by motor imagery was also recruited by working memory, while by comparison only 28% of the motor imagery network was also recruited by movement execution. To ensure this difference was not due to variations in overall network sizes, volume-matched analyses were conducted and confirmed a consistent effect but with less dramatic difference (36% of the motor imagery network was also recruited by working memory, compared with 32% for movement execution). Analyses by brain areas indicated that the greater overlap between motor imagery and working memory was primarily due to greater activation in frontal and parietal areas. These findings highlight that motor imagery may place a greater emphasis on cognitive processing than has been assumed by previous models and suggests that central executive processes may play an important role in motor imagery.