Planning versus Online Control in Real and Imagined Actions
Scott Glover
Royal Holloway University of London

Discrete movements such as reaching and grasping can be divided into two stages. Prior to movement initiation, a planning stage selects an appropriate motor program, whereas during execution, an online control stage monitors and, if need be, adjusts the action in flight. An interesting functional distinction between these two stages is that whereas planning processes are largely accessible to consciousness, online control processes are automatic and unconscious, a fact that has implications for how planning and control are represented in motor imagery. In recent studies, we have shown that whereas motor imagery is accurate at representing the output of action planning, the output of online control relies instead on biased cognitive time estimation processes. A planning-control account of motor imagery is also able to explain many of the other discrepancies between real and imagined actions.