Friesen W O, Stent G S
Annu Rev Biophys Bioeng. 1978;7:37-61. doi: 10.1146/annurev.bb.07.060178.000345.
Inasmuch as the identified neural circuits discussed in this review pertain only to the nervous systems of two invertebrate species, one may ask whether or not these findings are generally applicable to central nervous oscillators that generate rhythmic movements in animals of other species and phyla, particularly in the vertebrates. This question is not easy to answer at this time, because detailed cellular network analyses thus far have been possible only in a very few neurophysiologically favorable preparations, such as those presented by the cardiac and stomatogastric ganglia of the lobster and the segmental ganglion of the leech. Nevertheless it is significant that the mechanisms according to which these invertebrate circuits are now thought to generate their oscillations--endogenous rhythmic polarization, reciprocal inhibition, and recurrent cyclic inhibition--were all first proposed to account for generation of rhythmic movements in vertebrate animals (7-9, 51, 71, 79). Moreover, the pattern of motor neuron activity in rhythmic movements of vertebrates is not necessarily more complex than the corresponding pattern in analogous movements of invertebrates. Therefore, the very much greater number of neurons in the central nervous system of vertebrates does not necessarily imply a greater complexity of the central oscillators that generate their rhythmic movements; it may only place greater obstacles in the way of identifying the underlying neuronal circuitry. In any case, it is worthy of note that the current list of fundamentally different and theoretically plausible types of neuronal oscillators is not only quite short but also of long standing. Thus, on these grounds, it seems reasonable to expect that the identified circuits discussed here will prove to be of general applicability to the generation of rhythmic movements in the whole animal kingdom.
鉴于本综述中所讨论的已确定神经回路仅涉及两种无脊椎动物的神经系统，有人可能会问，这些发现是否普遍适用于在其他物种和门的动物，特别是脊椎动物中产生节律性运动的中枢神经振荡器。目前这个问题并不容易回答，因为迄今为止，详细的细胞网络分析仅在极少数神经生理学条件适宜的标本中才有可能实现，比如龙虾的心脏和口胃神经节以及水蛭的节段神经节所呈现的标本。然而，重要的是，目前认为这些无脊椎动物回路产生振荡的机制——内源性节律性极化、相互抑制和反复循环抑制——最初都是为了解释脊椎动物中节律性运动的产生而提出的(7 - 9, 51, 71, 79)。此外，脊椎动物节律性运动中运动神经元活动的模式并不一定比无脊椎动物类似运动中的相应模式更复杂。因此，脊椎动物中枢神经系统中神经元数量多得多并不一定意味着产生节律性运动的中枢振荡器更复杂；这可能只是给识别潜在的神经回路带来了更大的障碍。无论如何，值得注意的是，目前从根本上不同且理论上合理的神经元振荡器类型清单不仅相当短，而且由来已久。因此，基于这些理由，预计这里所讨论的已确定回路将被证明对整个动物王国中节律性运动的产生具有普遍适用性，这似乎是合理的。
