In the neurosciences, motor imagery (MIm) has not just been a topic of basic research. It has also attracted attention in applied research as a therapeutic tool. MIm is conceptualized as an internal simulation of motor acts that generates images on the basis of motor representations. Therefore, MIm is associated with neural activation of the cortical and subcortical motor system. The resulting concept of functional equivalence between MIm and execution opens a window to study the organization of motor processes and, more generally, to understand the neural plasticity of the motor system.