Centre for Neuroscience, University of Alberta, Edmonton, AB, Canada.
IEEE Trans Neural Syst Rehabil Eng. 2011 Feb;19(1):79-83. doi: 10.1109/TNSRE.2010.2052832. Epub 2010 Sep 2.
Intraspinal microstimulation (ISMS) employs electrical stimulation of the ventral grey matter to reactivate paralyzed skeletal muscle. This work evaluated the transformations in the quadriceps muscle that occurred following complete transection and chronic stimulation with ISMS or a standard nerve cuff (NCS). Stimulation was applied for 30 days, 4 h/day. Both methods induced significant increases in time-to-peak tension (ISMS 35%, NCS 25%) and half rise-time (ISMS 39%, NCS 25%) compared to intact controls (IC). Corresponding increases in type-IIA myosin heavy chain (MHC) and decreases in type-IID MHC were noted compared to IC. These results were unexpected because ISMS recruits motor units in a near-normal physiological order while NCS recruits motor units in a reversed order. Spinal cord transection and 30 days of stimulation did not alter either recruitment profile. The slope of the force recruitment curves obtained through ISMS following transection and 30 days of stimulation was similar to that obtained in intact animals, and 3.4-fold shallower than that obtained through NCS. The transformations observed in the current work are best explained by the near maximal level of motor unit recruitment, the total daily time of activity and the tonic nature of the stimulation paradigm.
脊髓内微刺激（ISMS）采用电刺激腹灰质来重新激活瘫痪的骨骼肌。这项工作评估了完全横断后和慢性 ISMS 或标准神经袖（NCS）刺激下股四头肌发生的变化。刺激持续 30 天，每天 4 小时。与完整对照组（IC）相比，两种方法都显著增加了峰值张力时间（ISMS 增加 35%，NCS 增加 25%）和半上升时间（ISMS 增加 39%，NCS 增加 25%）。与 IC 相比，还观察到 IIA 型肌球蛋白重链（MHC）的相应增加和 IIID MHC 的减少。这些结果出乎意料，因为 ISMS 以近乎正常的生理顺序募集运动单位，而 NCS 则以相反的顺序募集运动单位。脊髓横断和 30 天的刺激都没有改变这两种募集模式。横断和 30 天后通过 ISMS 获得的力募集曲线的斜率与在完整动物中获得的斜率相似，比通过 NCS 获得的斜率浅 3.4 倍。目前工作中观察到的变化可以通过接近最大水平的运动单位募集、每日活动的总时间和刺激范式的紧张性质来最好地解释。
