Mechanosensory inputs to the central pattern generators for locomotion in the lamprey spinal cord: resetting, entrainment, and computer modeling.
Mechanosensory inputs to the central pattern generators for locomotion in the lamprey spinal cord: resetting, entrainment, and computer modeling.
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DOI：
10.1152/jn.1993.70.6.2442
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发表时间：
1993-12
影响因子：
2.5
通讯作者：
Andrew D. McClellan;Woochan Jang
中科院分区：
文献类型：
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作者：
Andrew D. McClellan;Woochan Jang
1. 七鳃鳗脊髓中的机械感受器向中枢模式发生器（CPG）输入运动信号。在本研究中，施加正弦和脉冲运动在离体七鳃鳗脊髓末端，以激发机械感受器，从而研究运动节律的夹带和重置之间的关系。2. 正弦波运动对运动节律的影响范围是不对称的，主要发生在运动周期时间低于静息周期时间。在最短的周期时间内，运动阶段相对较小。3. 相位响应曲线（prc）显示，在运动周期的前半段施加运动脉冲的周期时间（相位提前）最大，而在运动周期的后半段施加运动脉冲的周期时间基本无效。PRC的相移幅度与夹带发生的周期时间范围相关。4. 在周期早期应用的运动脉冲复位期间，周期的突发和间歇部分缩短了大约相同的百分比。此外，复位效应沿脊髓同时发生，表明时间信息的快速分布。5. CPGs的计算机模型由左右振荡器和机械感觉元件的输入组成，产生了围绕休息周期时间对称的携带范围。模型中的prc显示了在周期的前半段应用的运动脉冲的相位提前和在周期的后半段应用的脉冲的相位延迟。6. 由于七鳃鳗脊髓的实验prc不对称，因此将门控纳入cooffter模型，使模型一侧的振荡器对来自同一侧机械感觉元件的输入进行门控。通过门控，该模型产生的夹带范围是不对称的，并且局限于低于静息周期时间的周期时间。对于周期开始时施加的脉冲，prc仍然显示出相位提前，并且与没有门控的模拟相比，在周期后半段产生的相位延迟量大大减少。
1. Mechanoreceptors in the lamprey spinal cord have inputs to the central pattern generator (CPG) for locomotion. In the present study, imposed sinusoidal and pulsed movements were applied to the end of the in vitro lamprey spinal cord to excite the mechanoreceptors so that the relationship between entrainment and resetting of the locomotor rhythm could be examined. 2. The range over which the locomotor rhythm could be entrained by sinusoidal movements was asymmetric and occurred mostly at movement cycle times below the resting cycle time. During entrainment at the shortest cycle times, the movement phases were relatively small. 3. The phase response curves (PRCs) displayed the greatest shortening of cycle times (phase advance) for movement pulses applied during the first half of the locomotor cycle, whereas movement pulses applied during the second half of the cycle were largely ineffective. The amplitude of phase shifts in the PRC correlated with the ranges of cycle times over which entrainment occurred. 4. During resetting from movement pulses applied early in the cycle, the burst and interburst parts of the cycle shortened by about the same percentage. In addition, resetting effects occurred simultaneously along the spinal cord, suggesting a rapid distribution of timing information. 5. A computer model of the CPGs, consisting of left and right oscillators and inputs from mechanosensory elements, produced entrainment ranges that were symmetric around the resting cycle time. The PRCs from the model showed phase advance for movement pulses applied during the first half of the cycle and phase delay for pulses applied during the second half of the cycle. 6. Because of the asymmetric experimental PRCs for the lamprey spinal cord, gating was incorporated into the cooffter model such that oscillators on one side of the model gated inputs from mechanosensory elements on the same side. With gating, the model produced entrainment ranges that were asymmetric and confined to cycle times below the resting cycle time. The PRCs still showed phase advance for pulses applied at the beginning of the cycle, and the amount of phase delay produced during the second half of the cycle was substantially reduced compared with the simulations without gating.