抄録
The central pattern generator (CPG) in the spinal cord oscillates a motor command to produce rhythmic movement, whereas several studies have described the movement frequency coding in the primary motor cortex and other motor area. However it is still unclear that the modulation of excitability in the cortico-spinal tract during rhythmic movement. We assessed cortico-spinal excitability during rhythmic movement using transcranial magnetic simulation (TMS), and analyzed the changing CPG frequency characteristic. When the subject performed rhythmic finger flexion-extension movements, TMS was applied on the primary motor cortex. Then the amplitude of the motor evoked potential (MEP) was measured on the target muscle. The frequency of the movement was varied between 0.5 and 4 Hz. We confirmed attenuated MEP was observed at 3 Hz for the finger rhythmic movements. We concluded that the motor command producing the rhythmic movement from motor cortex was decreased during specific rhythmic movement.
