Motor Planning, Not Execution, Separates Motor Memories.
Recent theories of limb control emphasize motor cortex as a dynamical system, with planning setting the initial neural state, and execution arising from the self-limiting evolution of the intrinsic neural dynamics. Therefore, movements that share an initial trajectory but then diverge might have different neural states during the execution of the identical initial trajectories. We hypothesized that motor adaptation maps neural states to changes in motor command. This predicts that two opposing perturbations, which interfere when experienced over the same movement, could be learned if each is associated with a different plan even if not executed. We show that planning, but not executing, different follow-through movements allow opposing perturbations to be learned simultaneously over the same movement. However, no learning occurs if different follow throughs are executed, but not planned prior to movement initiation. Our results suggest neural, rather than physical states, are the critical factor associated with motor adaptation.
Computational and Biological Learning Laboratory, Department of Engineering, Cambridge University, Cambridge, CB2 1PZ, UK.
Hannah R
HR
Sheahan
Computational and Biological Learning Laboratory, Department of Engineering, Cambridge University, Cambridge, CB2 1PZ, UK; Department of Sport and Health Sciences, Technical University of Munich, 80992 Munich, Germany.
David W
DW
Franklin
Computational and Biological Learning Laboratory, Department of Engineering, Cambridge University, Cambridge, CB2 1PZ, UK. Electronic address: wolpert@eng.cam.ac.uk.
Daniel M
DM
Wolpert
D000222:Adaptation, Physiological; D000328:Adult; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology; D008297:Male; D008568:Memory / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance; D055815:Young Adult