Abstract
In the previous report, electromyographical examination of the effect of anesthetics showed that the standing posture was influenced by the variation of the mode of fixation on the hind-limb joints. Especially, it should be noted that the fixation of the knee joint and paralysis of hind quarters were closely related to each other. In this investigation, the influence of anesthesia exerted upon the nervous mechanism which controls the muscular activity was examined by analyzing the fluctuation of the discharge-interval-time series of a single NMU. In two dogs which had been trained in maintaining the normal standing posture for a long time, the spike discharge of a single NMU was recorded from the flexor muscles of the forelimb, M. quadriceps femoris, and M. gastrocnemius. The discharge intervals measured from the record and the τ-S relation diagram were used as refernces for discussion. The results obtained dre summarized as follows. (1) In the case of the forelimb muscle, corticalization occurred at all the stages of anesthesia; that is, the initial, anesthetic, and recovery stages. (2) In the case of the hind-limb muscle, spinalization occurred at the initial stage. This phenomenon appeared about two minutes after administration of the drug. At the recovery stage, the control by both spinal and cortical nervous systems occurred on the muscle.
