Pattern of cortical activation encodes subjective phantom limb movement

Subjective movability of phantom hand has been suggested to relate to phantom pain; however, cortical activities that represent the movement of phantom hand is unclear. Here, we recorded magnetoencephalographic signals while phantom limb patients moved their phantom hand and compared with the subjective movability of the phantom hand. During the experiment, the patients with phantom limb pain performed grasping and opening of phantom, and intact hands. Cortical potentials in the sensorimotor cortex contralateral to the tested hand were estimated from the magneto encephalographic signals, and used to infer movement type. Subjective movabili ty of the phantom hands were evaluated by duration of time required to perform grasping and opening. During movement of phantom hand, sensorimotor cortex contralateral to the phantom hand was activated similarly to the movement of intact hand. The decoding accuracy of movement type of phantom hand was deterio-rated in the patient who was not able to move his phantom hand fast. In conclusion, it was suggested that the decoding accuracy of phantom hand movement represented the subjective movability of the phantom hand.