4e7a01fd-3239-422c-94f2-2f6993105288

Motor imagery changes the nervous system over time. Training studies in which participants repeatedly imagine maximal contractions of a specific muscle group, without lifting anything, show increases in measured strength after weeks of practice. Meta-analyses of these experiments report gains on the order of ten to twenty percent, accompanied by changes in cortical excitability rather than muscle hypertrophy. The adaptation occurs in the circuits that plan and initiate movement, not in the fibers that ultimately carry it out. The pattern appears in older adults as well. Recent work in Frontiers in Psychology and related journals finds that motor imagery training can improve maximal voluntary contraction and reduce co-contraction of antagonist muscles in healthy older participants. The nervous system refines how it recruits existing muscle, coordinating agonists and antagonists more efficiently, as if practice in the realm of imagination has tuned the timing of commands before they ever become force. Phantom limb pain after amputation reveals another way imagination and body sensations are intertwined. Many amputees continue to feel the presence of the missing limb, sometimes with intense pain, even though the physical source of that sensation is gone. Neuroimaging studies show reorganization in the primary sensory and motor cortices regions once devoted to the missing limb become responsive to inputs from neighboring body parts. The representation of the limb persists in the brain, and it is that representation, dissociated from incoming signals, that appears to generate the experience.