Heterogeneity and central modulation of feedback reflexes in crayfish motor pool.
Heterogeneity and central modulation of feedback reflexes in crayfish motor pool.
复制标题
小龙虾运动池反馈反射的异质性和中枢调节。
DOI：
10.1152/jn.1992.67.3.648
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发表时间：
1992
影响因子：
2.5
通讯作者：
B. Bush
中科院分区：
文献类型：
--
作者：
P. Skorupski;B. Rawat;B. Bush
1. 小龙虾胸尾腿关节的运动由肌肉感受器（TCMRO）和弦音器（TCCO）监测。两个感受器平行跨越关节，但发出相反方向的腿部运动信号。 TCMRO 受到对延长有反应的传入神经支配，这对应于腿部的移动，而 TCCO 传入神经对脊索音链的缩短有反应，这对应于腿部的提升。 2.当两个受体在单独的制剂中同时受到刺激时，在拉伸和释放时都会发生髋部启动子和远端运动神经元的反射反应。通过与选择性刺激这些受体中的一种或另一种的实验进行比较，我们得出结论，两种受体的拉伸引起的反射是由于TCMRO，而释放引起的反射是由于TCCO。 3. 由这些受体介导的反射是状态依赖性和相位依赖性的。在启动子和遥控运动神经元（活跃状态）中产生相互运动活动模式的制剂中，反射效果取决于这种中枢产生的活动的阶段。在静止或仅产生强直运动输出（非活性状态）的制剂中，反射效果是稳定的，对应于受体运动两个方向的典型阻力（负反馈）反射。 4.在激活状态下，通过拉伸TCMRO，轴侧启动运动神经元以相位依赖的方式被兴奋和抑制。启动子运动神经元的一个亚群通过缩短 TCCO 而受到兴奋。拮抗性轴轴运动神经元的一个亚群接收来自 TCMRO 拉伸的相位依赖性兴奋，而第二个亚群则接收来自缩短 TCCO 的相位依赖性兴奋。 5. 因此，至少有两种方法可以调节反射效应。在单个运动神经元的水平上，反射反应的增益可以变化，在某些情况下，信号也可以变化，其方式取决于中枢产生的运动活动。此外，在协同运动神经元池的水平上，反射效果并不均匀；相反，不同的运动神经元亚群表现出不同的反射效应，因此不同运动神经元反射亚群的兴奋性相对水平也可以决定净反射效应。 6. TCCO 缩短对启动运动神经元的兴奋和 TCMRO 延长对运动运动神经元的兴奋是正反馈反射。在启动子池和调节池中均可引起正反馈反射的运动神经元亚群被称为第 1 组。（摘要截断为 400 字）
1. Movement of the crayfish thoracocoxal leg joint is monitored by a muscle receptor organ (TCMRO) and a chordotonal organ (TCCO). Both receptors span the joint in parallel but signal opposite directions of leg movement. The TCMRO is innervated by afferents responsive to lengthening, which corresponds to leg remotion, whereas TCCO afferents are responsive to shortening of the chordotonal strand, which corresponds to leg promotion. 2. When both receptors are stimulated in parallel, in an otherwise isolated preparation, reflex responses of coxal promoter and remotor motor neurons occur on both stretch and release. By comparison with experiments where one or the other of these receptors is stimulated selectively, we conclude that reflexes evoked by stretch of the two receptors are due to the TCMRO and reflexes evoked by release are due to the TCCO. 3. Reflexes mediated by these receptors are both state dependent and phase dependent. In preparations that produce patterns of reciprocal motor activity in promotor and remotor motor neurons (the active state), the reflex effect depends on the phase of this centrally generated activity. In preparations that are quiescent, or that produce only tonic motor output (the inactive state), the reflex effect is stable, corresponding to a typical resistance (negative feedback) reflex for both directions of receptor movement. 4. In the active state, coxal promotor motor neurons are both excited and inhibited in a phase-dependent manner by stretching the TCMRO. A subgroup of promotor motor neurons is excited by shortening the TCCO. One subgroup of the antagonistic coxal remotor motor neurons receives phase-dependent excitation from stretch of the TCMRO, whereas a second subgroup receives phase-dependent excitation from shortening the TCCO. 5. There are, therefore, at least two ways in which reflex effects can be modulated. At the level of a single motor neuron, the reflex response can vary in gain, and in some cases in sign, in a manner depending on centrally generated motor activity. In addition, at the level of a pool of synergistic motor neurons, the reflex effect is not uniform; instead, different subgroups of motor neurons display different reflex effects, so that the relative levels of excitability of different motor neuron reflex subgroups can also determine the net reflex effect. 6. Excitation of promotor motor neurons by TCCO shortening and of remotor motor neurons by TCMRO lengthening are positive feedback reflexes. The subgroups of motor neurons in which positive feedback reflexes can be evoked in both promotor and remotor pools are termed group 1.(ABSTRACT TRUNCATED AT 400 WORDS)