Short-Term Synaptic Plasticity at Interneuronal Synapses Could Sculpt Rhythmic Motor Patterns.
Short-Term Synaptic Plasticity at Interneuronal Synapses Could Sculpt Rhythmic Motor Patterns.
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DOI：
10.3389/fncir.2016.00004
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发表时间：
2016
影响因子：
3.5
通讯作者：
Parker D
中科院分区：
文献类型：
--
作者：
Jia Y;Parker D
神经元网络的输出取决于其组成细胞和突触的组织和功能特性。虽然突触特性的表征已经落后于细胞分析，但节律性活动网络中的一个潜在重要方面是网络突触如何影响网络活动，并反过来受到网络活动的影响。这可能导致一个潜在的循环相互作用，其中短期活动依赖性突触可塑性既受到网络输出的影响，也影响网络输出。在七鳃鳗运动网络的突触可塑性的分析扩展到这里来表征网络中间神经元之间的连接的短期可塑性，并试图解决其潜在的网络作用。从静态网络中识别的中间神经元的配对记录显示突触特异性突触特性和可塑性，支持存在两个半节段组，可以影响爆裂：抑郁症的兴奋性中间神经元组，和促进抑制性反馈电路。通过改变Ringer Ca ~（2+）水平，并在一个简单的计算机模型中，实验研究了活动依赖性突触可塑性对网络活动的影响。实验分析的一个潜在警告是，林格氏钙离子的变化（在某些情况下，镁离子的补偿性调节）可能会改变其他几种细胞和突触特性。对其中几个属性进行了测试，虽然存在一些变异性，但这些属性通常不会受到林格氏变化的显著影响。实验分析表明，兴奋性输入的抑制对网络活动的模式有最强的影响。该模拟支持了这种作用，也表明抑制性促进组可以调节兴奋性突触抑制的影响。在脊髓模型中，短期活动依赖性突触可塑性通常未被考虑。这些结果为运动网络中间神经元之间的短期可塑性提供了进一步的证据。由于这种可塑性可以影响网络输出的模式，因此应将其视为脊髓网络的潜在功能成分。
The output of a neuronal network depends on the organization and functional properties of its component cells and synapses. While the characterization of synaptic properties has lagged cellular analyses, a potentially important aspect in rhythmically active networks is how network synapses affect, and are in turn affected by, network activity. This could lead to a potential circular interaction where short-term activity-dependent synaptic plasticity is both influenced by and influences the network output. The analysis of synaptic plasticity in the lamprey locomotor network was extended here to characterize the short-term plasticity of connections between network interneurons and to try and address its potential network role. Paired recordings from identified interneurons in quiescent networks showed synapse-specific synaptic properties and plasticity that supported the presence of two hemisegmental groups that could influence bursting: depression in an excitatory interneuron group, and facilitation in an inhibitory feedback circuit. The influence of activity-dependent synaptic plasticity on network activity was investigated experimentally by changing Ringer Ca2+ levels, and in a simple computer model. A potential caveat of the experimental analyses was that changes in Ringer Ca2+ (and compensatory adjustments in Mg2+ in some cases) could alter several other cellular and synaptic properties. Several of these properties were tested, and while there was some variability, these were not usually significantly affected by the Ringer changes. The experimental analyses suggested that depression of excitatory inputs had the strongest influence on the patterning of network activity. The simulation supported a role for this effect, and also suggested that the inhibitory facilitating group could modulate the influence of the excitatory synaptic depression. Short-term activity-dependent synaptic plasticity has not generally been considered in spinal cord models. These results provide further evidence for short-term plasticity between locomotor network interneurons. As this plasticity could influence the patterning of the network output it should be considered as a potential functional component of spinal cord networks.