The Midbrain Precommand Nucleus of the Mormyrid Electromotor Network
The Midbrain Precommand Nucleus of the Mormyrid Electromotor Network
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斑鸠电机网络的中脑前指令核
DOI：
10.1523/jneurosci.20-14-05483.2000
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
K. Grant
中科院分区：
文献类型：
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作者：
G. von der Emde;Leonel Gómez Sena;Rafaella Niso;K. Grant
采用细胞外记录场电位、单细胞活动和活体微刺激技术，研究了弱电拟鱼Gnathonemuspetersii中脑前指挥核（PCN）的功能。PCN中的电动机相关场电位以一对一的方式与电器官放电（EOD）命令周期有固定的时间关系，但发生在延髓中的EOD命令活动之后。这表明，PCN电动机相关的场电位产生于两个来源：（1）逆向，通过反向传播跨越PCN轴突和命令核神经元之间的电紧张性突触，和（2）作为必然的放电驱动反馈间接到达命令核，通过多突触通路。PCN神经元可以被电感觉输入激活，但这并不一定激活整个运动命令链。对PCN的微刺激以一种可以模仿某些刻板行为模式结构的方式调节电动机命令的内源性模式。PCN活性的调节，并在一定程度上同步，由必然的放电反馈抑制。然而，PCN通常不作为驱动UART命令链的同步起搏器。我们认为，PCN神经元整合各种来源的信息，并单独中继到延髓的指挥核。有些也可能有内在的，虽然通常是非同步的，起搏器的属性。这种下行活动，整合在中央指令核，将在中央模式发生器的决策过程中发挥重要的调节作用。
The functional role of the midbrain precommand nucleus (PCN) of the electromotor system was explored in the weakly electric mormyrid fishGnathonemus petersii, using extracellular recording of field potentials, single unit activity, and microstimulationin vivo. Electromotor-related field potentials in PCN are linked in a one-to-one manner and with a fixed time relationship to the electric organ discharge (EOD) command cycle, but occur later than EOD command activity in the medulla. It is suggested that PCN electromotor-related field potentials arise from two sources: (1) antidromically, by backpropagation across electrotonic synapses between PCN axons and command nucleus neurons, and (2) as corollary discharge-driven feedback arriving from the command nucleus indirectly, via multisynaptic pathways. PCN neurons can be activated by electrosensory input, but this does not necessarily activate the whole motor command chain. Microstimulation of PCN modulates the endogenous pattern of electromotor command in a way that can mimic the structure of certain stereotyped behavioral patterns. PCN activity is regulated, and to a certain extent synchronized, by corollary discharge feedback inhibition. However, PCN does not generally function as a synchronized pacemaker driving the electromotor command chain. We propose that PCN neurons integrate information of various origins and individually relay this to the command nucleus in the medulla. Some may also have intrinsic, although normally nonsynchronized, pacemaker properties. This descending activity, integrated in the electromotor command nucleus, will play an important modulatory role in the central pattern generator decision process.