1) Utilizing involuntary movement patients, GP, thalamus and their neibouring structure were electrically studied by depth electrodes, at rest and activated states. In addition to it, stretch reflex and H-wave of EMG at stimulation were analyzed. 2) Electroencephalography of GP reveals 10-12 cps, α-band, sinewave at rest. However, thalamus and TC represent faster waves of nothing characteristic in resting EEG. It is to be noted that these EEG manifestation would not be altered by stimulation. 3) Stimulation of GP causes increased stretch reflex, but no alternation in H-wave. Stimulation of TC manifests increased amplitude of H-wave without causing any change in stretch reflex. Nothing could be found at stimulation of thalamus. 4) It appeares to be concluded that TC, involving pyramidal tract in internal capsule, causes the increment of α-system excitability at stimulation and, in contrast, GP stimulation represents an increment of γ-system excitability.