MECHANISMS OF PATTERN GENERATION UNDERLYING SWIMMING IN TRITONIA .1. NEURONAL NETWORK FORMED BY MONO-SYNAPTIC CONNECTIONS
MECHANISMS OF PATTERN GENERATION UNDERLYING SWIMMING IN TRITONIA .1. NEURONAL NETWORK FORMED BY MONO-SYNAPTIC CONNECTIONS
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DOI：
10.1152/jn.1981.46.1.65
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发表时间：
1981-01-01
影响因子：
2.5
通讯作者：
GETTING, PA
中科院分区：
文献类型：
--
作者：
GETTING, PA
海洋软体动物T. diomedea由至少3个大脑中间神经元群体组成的网络产生。这些中间神经元群被称为C2、背侧游泳中间神经元（DSI）和腹侧游泳中间神经元（VSI）。报道了10个已鉴定的游泳中间神经元之间的单突触连接。单突触连接通过5个标准进行评估，包括：在高钙/高镁海水中的持久性，一对一的后续，与突触前刺激强度的分级，突触前四乙基铵（TEA）离子注射的调制和突触前电压的调制。化学介导的单突触连接只观察到同侧游泳中间神经元之间。这些连接可分为兴奋性、抑制性和兴奋与抑制相结合的多成分突触电位。单突触连接的模式密切平行的功能之间观察到的相互作用的游泳interneurons在静止的准备工作。两侧单突触相互作用仅限于两侧同源细胞之间的电子耦合。未观察到化学介导的对侧单突触连接。单突触电位的时程相差高达30倍，这表明一些突触相互作用仅在单个突触前爆发或单个游泳周期期间有效，而其他突触相互作用可能在许多周期内起作用。多组分突触电位在模式生成中的作用进行了讨论，在每个组件相对于周期的时间过程。由单突触连接形成的模式生成网络依赖于突触介导的兴奋与抑制的相互作用。
The motor program underlying swimming in the marine mollusk, T. diomedea, is generated by a network consisting of at least 3 populations of cerebral interneurons. These interneuron populations are termed C2, dorsal swim interneurons (DSI) and ventral swim interneurons (VSI). The monosynaptic connectivity among the 10 identified swim interneurons is reported. Monosynaptic connections were assessed by 5 criteria including: persistence in high-Ca/high-Mg seawater, one-for-one following, gradation with presynaptic stimulus strength, modulation by presynaptic tetraethylammonium (TEA) ion injection and modulation by presynaptic voltage. Chemically mediated monosynaptic connections were observed only between ipsilateral swim interneurons. These connections fell into 3 categories: excitatory, inhibitory or multicomponent synaptic potentials combining excitation with inhibition. The pattern of monosynaptic connectivity closely parallels the functional interactions observed between the swim interneurons in quiescent preparations. Contralateral monosynaptic interactions are restricted to electronic coupling between bilaterally homologous cells. No chemically mediated contralateral monosynaptic connections were observed. The time courses of the monosynaptic potentials differ by a factor of up to 30, suggesting that some of the synaptic interactions are effective only during a single presynaptic burst or a single swim cycle, while others may act over many cycles. The role of multicomponent synaptic potentials in pattern generation is discussed in terms of the time course of each component relative to cycle period. The pattern-generating network formed by the monosynaptic connections relies on the interplay of synaptically mediated excitation with inhibition.