Modularity of motor output evoked by intraspinal microstimulation in cats
Modularity of motor output evoked by intraspinal microstimulation in cats
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DOI：
10.1152/jn.00235.2003
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发表时间：
2004-01-01
影响因子：
2.5
通讯作者：
Grill, WM
中科院分区：
文献类型：
--
作者：
Lemay, MA;Grill, WM
在脊髓完整的α-氯醛糖麻醉动物(n=3)和去大脑动物(n=3)上，我们研究了微刺激IPSI和对侧腰段脊髓对猫后爪产生的力。测量了9-12个肢体构型的等长力和肌电反应，将爪子连接到力传感器上，并固定髋部和股骨。在不同的肢体构型上产生的作用力被总结为代表整个工作空间中爪子所产生的力的矢状面分量的力场。力的幅度随时间变化，但方向是稳定的，活动力场的模式随时间不变。主动力场分为四种不同的类型，其中一些场收敛到一个平衡点。这些区域通常是后肢肌肉共同激活所产生的。此外，其中一些区域与已知的脊髓反射一致，产生这些反射的刺激部位位于与这些反射相关的中间神经元所在的板层。脊髓内刺激所产生的肌肉激活(通过肌肉内肌电活动来评估)被肢体构型改变，这表明这种反应不是固定的，而是被位置依赖的感觉反馈所改变。力反应可能代表脊髓回路的基本输出，并可能与在青蛙和大鼠中发现的类似的脊髓原始细胞有关。
We studied the forces produced at the cat's hindpaw by microstimulation of the ipsi- and contralateral lumbar spinal cord in spinal intact alpha-chloralose anesthetized (n=3) or decerebrate (n=3) animals. Isometric force and EMG responses were measured at 9-12 limb configurations, with the paw attached to a force transducer and with the hip and femur fixed. The active forces elicited at different limb configurations were summarized as force fields representing the sagittal plane component of the forces produced at the paw throughout the workspace. The forces varied in amplitude over time but the orientations were stable, and the pattern of an active force field was invariant through time. The active force fields divided into four distinct types, and a few of the fields showed convergence to an equilibrium point. The fields were generally produced by coactivation of the hindlimb muscles. In addition, some of the fields were consistent with known spinal reflexes and the stimulation sites producing them were in laminae where the interneurons associated with those reflexes are known to be located. Muscle activation produced by intraspinal stimulation, as assessed by intramuscular EMG activity, was modified with limb configuration, suggesting that the responses were not fixed, but were modified by position-dependent sensory feedback. The force responses may represent basic outputs of the spinal circuitry and may be related to similar spinal primitives found in the frog and rat.