Clarifying the scope and boundaries of the motor simulation theory: A constructive perspective for motor imagery research.

Motor imagery has attracted renewed interest in recent years, along with renewed debate about the Motor Simulation Theory, which posits activation of motor-related neural systems to internally simulate action without execution. While recent work has clarified some empirical limits of imagery, particularly in feedback-based learning, other critiques misinterpret the theory's core assumptions. This paper distinguishes between empirically grounded challenges that refine the Motor Simulation Theory, such as those involving executive processes and partial motor activation, and conceptual misunderstandings that mischaracterize the theory. Claims that the theory predicts exact timing equivalence or complete neural overlap with action execution, or supports sensorimotor adaptation overlook the functional equivalence principle at its foundation. We also argue that alternative, behaviorally focused theories often neglect robust neurophysiological evidence underpinning the Motor Simulation Theory. We advocate for an integrated perspective that maintains its predictive value while accommodating valid critiques, aiming to clarify its boundaries and relevance for imagery research.