A separate local pattern-generating circuit controls the movements of each swimmeret in crayfish.
A separate local pattern-generating circuit controls the movements of each swimmeret in crayfish.
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一个单独的局部模式生成电路控制小龙虾中每个游泳足的运动。
DOI：
10.1152/jn.1993.70.6.2620
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发表时间：
1993
影响因子：
2.5
通讯作者：
Mulloney,B
中科院分区：
文献类型：
--
作者：
Murchison,D;Chrachri,A;Mulloney,B
1. 在腹节内，从节段神经节到游泳足的运动输出由支配左右肢的不同运动神经元池中的协调脉冲组成。这种协调运动模式的特点是在动力冲程 (PS) 和回程 (RS) 运动轴突中交替（异相）脉冲爆发，支配每个游泳足。每个段两侧的 PS 突发同时发生（同相），因此两侧的 RS 突发也是同相的。 2. 在所有节段间连接中断的情况下，孤立的腹部神经节能够维持双侧同相的交替 PS/RS 活动的正常游泳足运动模式。 3. 通过手术将孤立的神经节沿中线一分为二后，所形成的孤立的半神经节可以产生稳定、协调的 PS 和 RS 爆发交替。 4.当河豚毒素(TTX)阻断尖峰时，神经肽proctolin可诱导游泳足神经元膜电位的节律性振荡。对于同一半神经节内的神经元，这些振荡保留了与对照组相同的相位关系，但不同半神经节中神经元的振荡变得不协调。 5.在TTX存在的情况下，同一半神经节中游泳足神经元之间的突触传递持续存在。当 TTX 存在时，在控制条件下可以激活模式生成电路的游泳鱼中间神经元可以在同一半神经节的游泳鱼神经元中诱导膜电位振荡。 6. 我们得出结论，一个单独的半分段模式生成电路控制着每个游泳足的有节奏的 PS 和 RS 运动。每个回路都位于与支配局部游泳足的运动神经元群相同的半神经节中。分级传输足以协调半分段电路内振荡活动的时序。这些半节段回路通过节间和双边协调通路耦合，这些通路的运行依赖于钠动作电位。
1. Within an abdominal segment, the motor output from the segmental ganglion to the swimmerets consists of coordinated bursts of impulses in the separate pools of motor neurons innervating the left and right limbs. This coordinated motor pattern features alternating (out-of-phase) bursts of impulses in the power-stroke (PS) and return-stroke (RS) motor axons that innervate each swimmeret. PS bursts on both sides of each segment occur simultaneously (in-phase), and so RS bursts on both sides are also in-phase. 2. With all intersegmental connections interrupted, isolated abdominal ganglia were able to sustain the normal swimmeret motor pattern of alternating PS/RS activity that was bilaterally in-phase. 3. After an isolated ganglion was surgically bisected down the midline, the isolated hemiganglia that resulted could produce stable, coordinated alternation of PS and RS bursts. 4. The neuropeptide proctolin could induce rhythmic oscillations of membrane potential in swimmeret neurons when spiking was blocked by tetrodotoxin (TTX). For neurons within the same hemiganglion, these oscillations retained the same phase relations they displayed in controls, but the oscillations of neurons in different hemiganglia became uncoordinated. 5. Synaptic transmission between swimmeret neurons in the same hemiganglion persisted in the presence of TTX. Swimmeret interneurons that could activate the pattern-generating circuitry under control conditions could induce membrane-potential oscillations in swimmeret neurons of the same hemiganglion when TTX was present. 6. We conclude that a separate hemisegmental pattern-generating circuit controls the rhythmic PS and RS movements of each swimmeret. Each circuit is located in the same hemiganglion as the population of motor neurons that innervates the local swimmeret. Graded transmission is sufficient to coordinate the timing of oscillatory activity within the hemisegmental circuitry. These hemisegmental circuits are coupled by intersegmental and bilateral coordinating pathways that are dependent on sodium action potentials for their operation.