Generation of scratching. II. Nonregular regimes of generation.
Generation of scratching. II. Nonregular regimes of generation.
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刮擦的一代。
DOI：
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发表时间：
1978
影响因子：
2.5
通讯作者：
G. Orlovsky
中科院分区：
文献类型：
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作者：
M. B. Berkinblit;T. Deliagina;A. G. Feldman;I. Gelfand;G. Orlovsky
1.在模拟抓挠（5）过程中记录了肌肉神经和L4和L5节段脊髓中间神经元的活动，这是通过刺激颈脊髓在去大脑的猫中诱发的。在一些实验中，通过刺激第五腰椎背根（DL 5）来扰乱节律性产生。2.除了抓挠的开始，节律性的产生通常是相当有规律的：周期持续时间的波动小于+/-5%。但是刺激强度、刺激电极位置和后肢位置的变化导致产生机制的变化。在不同的制度，周期持续时间的平均值可以相差20- 30%。没有相关性之间的平均持续时间的屈肌和伸肌阶段的不同制度。3.只有当后肢处于“抓挠姿势”，即，向前偏转。当肢体向后偏转时，生成立即停止，并且当其返回到抓挠姿势时，生成立即开始。4.在一些实验中，颈脊髓的刺激首先导致产生具有步进的典型时间模式的缓慢振荡（周期持续时间约500 ms，屈肌和伸肌阶段几乎彼此相等）。然后，在5-20个周期期间，逐渐过渡到正常的划痕周期（约250 ms），主要是由于伸肌相的显著缩短（5-10倍）。在一些实验中，观察到相当大的自发变化的屈肌相，而伸肌相是恒定的。5.施加到DL 5的单一刺激显著影响循环持续时间。重复的DL 5刺激，与抓挠的节奏接近，导致同步的脊髓发生器的刺激。6.从缓慢的振荡到正常的划痕周期的过渡过程中记录的脊髓中间神经元只稍微改变了他们的活动阶段的运动神经元的活动。7.提出了一种假说，即不同类型的肢体运动的产生是由同一个中枢脊髓机制产生的，该机制可以在不同的机制中运作。感官输入的作用，这种机制的操作进行了讨论。
1. The activity of muscle nerves and that of spinal interneurons from the L4 and L5 segments was recorded during fictitious scratching (5), which was evoked in decerebrate curarized cats by stimulation of the cervical spinal cord. In some experiments, rhythmical generation was disturbed by stimulation of the fifth lumbar dorsal root (DL5). 2. Excluding the very beginning of scratching, rhythmical generation was usually rather regular: fluctuations of the cycle duration were less than +/-5%. But changes in the stimulation strength, in the stimulating electrode position, and in the hindlimb position led to changes of the generation regime. In different regimes, the mean value of the cycle duration could differ by 20-30%. No correlation was found between mean durations of flexor and extensor phases for different regimes. 3. Rhythmical generation was possible only if the hindlimb was put to "scratch posture," i.e., deflected forward. Generation immediately stopped when the limb was deflected backward, and immediately started when it was returned to scratch posture. 4. In some experiments, stimulation of the cervical spinal cord first resulted in generation of slow oscillations with the temporal pattern typical of stepping (cycle duration about 500 ms, flexor and extensor phases being almost equal to each other). Then, during 5-20 cycles, gradual transition to a normal scratch cycle (about 250 ms) occurred mainly due to considerable shortening (5-10 times) of the extensor phase. In some experiments, considerable spontaneous variations of the flexor phase were observed, while the extensor phase was constant. 5. A single stimulus applied to DL5 considerably affected the cycle duration. Repetitive DL5 stimulation,with a rhythm close to that of scratching, resulted in synchronization of the spinal generator by the stimuli. 6. Spinal interneurons recorded during transition from slow oscillations to a normal scratch cycle only slightly changed phases of their activity in relation to the activity of motoneurons. 7. A hypothesis is advanced that generation of different kinds of limb movements is produced by one and the same central spinal mechanism which can operate in different regimes. The role of sensory input for operation of this mechanism is discussed.