Composite modulatory feedforward loop contributes to the establishment of a network state.
Composite modulatory feedforward loop contributes to the establishment of a network state.
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DOI：
10.1152/jn.01054.2009
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发表时间：
2010-04
影响因子：
2.5
通讯作者：
Jin-sheng Wu;F. Vilim;N. Hatcher;Michael R. Due;J. Sweedler;K. R. Weiss;J. Jing
中科院分区：
文献类型：
--
作者：
Jin-sheng Wu;F. Vilim;N. Hatcher;Michael R. Due;J. Sweedler;K. R. Weiss;J. Jing
前馈回路（ffl）是在各种复杂网络中发现的众多网络基序之一，但其在神经网络中的功能作用尚未得到很好的理解。我们提供的证据表明，多个调制器的组合作用可能被组织为ffl，以促进applysia馈电电机网络中的特定网络状态。海雀进食中枢模式发生器（CPG）接受两种不同的输入——高阶脑-颊间神经元-2 （CBI-2）和食道神经（EN）——分别促进摄取和排泄运动程序。EN刺激引发了一个持续的释放网络状态，这使得网络能够在从EN到CBI-2的输入切换后暂时表达释放程序。先前的研究表明，一种调节性CPG元件B65被EN特异性激活，并通过增强促分泌的B20中间神经元的活性，抑制促摄入的B40中间神经元的活性和突触输出，参与建立分泌状态。这里的肽能作用是由小心脏活性肽（SCP）介导的。免疫染色和质谱分析表明，SCP存在于EN中，并在EN刺激下释放。重要的是，SCP直接增强B20的活性和突触输出，抑制B40的活性和突触输出。此外，SCP促进了B65的活性。因此，从SCPergic神经元到B20和B40的直接和间接通路（通过B65）构成了两种ffl，一种促进分泌输出，另一种抑制摄入输出。这种由两个结合的FFL组成的复合FFL似乎是一种有效的手段，可以共同调节两个相互竞争的元件的活性，从而有助于建立特定的网络状态。
Feedforward loops (FFLs) are one of many network motifs identified in a variety of complex networks, but their functional role in neural networks is not well understood. We provide evidence that combinatorial actions of multiple modulators may be organized as FFLs to promote a specific network state in the Aplysia feeding motor network. The Aplysia feeding central pattern generator (CPG) receives two distinct inputs-a higher-order interneuron cerebral-buccal interneuron-2 (CBI-2) and the esophageal nerve (EN)-that promote ingestive and egestive motor programs, respectively. EN stimulation elicits a persistent egestive network state, which enables the network to temporarily express egestive programs following a switch of input from the EN to CBI-2. Previous work showed that a modulatory CPG element, B65, is specifically activated by the EN and participates in establishing the egestive state by enhancing activity of egestion-promoting B20 interneurons while suppressing activity and synaptic outputs of ingestion-promoting B40 interneurons. Here a peptidergic contribution is mediated by small cardioactive peptide (SCP). Immunostaining and mass spectrometry show that SCP is present in the EN and is released on EN stimulation. Importantly, SCP directly enhances activity and synaptic outputs of B20 and suppresses activity and synaptic outputs of B40. Moreover, SCP promotes B65 activity. Thus the direct and indirect (through B65) pathways to B20 and B40 from SCPergic neurons constitute two FFLs with one functioning to promote egestive output and the other to suppress ingestive output. This composite FFL consisting of the two combined FFLs appears to be an effective means to co-regulate activity of two competing elements that do not inhibit each other, thereby contributing to establish specific network states.