Abstract
The central pattern generator (CPG) in the spinal cord oscillates a motor command to produce rhythmic movement. We assessed corticospinal excitability during rhythmic movement using transcranial magneticsimulation (TMS), and analyzed the changing CPG frequency characteristics. The subject performed rhythmic finger flexion-extension movements. A single-pulsed TMS was applied on the primary motor cortex, and the amplitude of the motor evoked potential (MEP) was measured on the target muscle after 10 s from the onset of movement. The frequency oscillation of the movement was varied between 1, 2, 3,and 4 Hz. Similarly, TMS was conducted during rhythmic lower limb pedaling at 0.5, 1, 2, and 3 Hz. MEP modulation was compared, and the attenuated MEP was observed at 4 Hz and 1 Hz for the finger and lower limb rhythmic movements, respectively. Therefore, the resonant frequency to produce smooth rhythmic movements was found to be associated with task specificity.
