Modulation of hippocampal rhythms by subthreshold electric fields and network topology.
Modulation of hippocampal rhythms by subthreshold electric fields and network topology.
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DOI：
10.1007/s10827-012-0426-4
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发表时间：
2013-06
影响因子：
1.2
通讯作者：
Ascoli, Giorgio A.
中科院分区：
文献类型：
--
作者：
Berzhanskaya, Julia;Chernyy, Nick;Gluckman, Bruce J.;Schiff, Steven J.;Ascoli, Giorgio A.
Theta（4-12 Hz）和Gamma（30-80 Hz）节律被认为对皮质和海马功能很重要。虽然有几种神经元类型与节律发生有关，但确切的细胞机制仍不清楚。阈下电场提供了一个灵活的，区域特定的工具来调节神经活动和直接测试功能假设。在这里，我们提出了海马突触电路，神经元形态，外部电场和网络活动之间的相互作用的实验和计算证据。电生理数据被用来约束和验证一个解剖学和生物病理学上的现实模型的区域CA 1含有锥体细胞和两个interneuron类型：树突状和perisomatic靶向。我们报告两行的结果：解决网络结构能够产生θ调制的伽马节律，并展示电场对这些节奏的影响。首先，θ调制的伽马节律需要特定的抑制连接。在一种构型中，对锥体细胞的GABA能轴-树突反馈仅在近端层而非远端层中有效。另一种配置需要两个不同的perisomatic中间神经元类，一个专门接收兴奋性接触，其他额外的抑制有针对性。这些观察表明，新的角色，特别是类oriens和篮细胞。第二个主要发现是阈下电场强烈地改变了不同节律之间的平衡。独立于网络配置，正电场减小，而负场增加θ/γ比。此外，电场差异影响平均θ频率取决于特定的突触连接。这些结果支持了阈下电场可以改变海马节律的可测试预测，提示了探索其认知功能和潜在电路的新方法。
Theta (4–12 Hz) and gamma (30–80 Hz) rhythms are considered important for cortical and hippocampal function. Although several neuron types are implicated in rhythmogenesis, the exact cellular mechanisms remain unknown. Subthreshold electric fields provide a flexible, area-specific tool to modulate neural activity and directly test functional hypotheses. Here we present experimental and computational evidence of the interplay among hippocampal synaptic circuitry, neuronal morphology, external electric fields, and network activity. Electrophysiological data are used to constrain and validate an anatomically and biophysically realistic model of area CA1 containing pyramidal cells and two interneuron types: dendritic- and perisomatic-targeting. We report two lines of results: addressing the network structure capable of generating theta-modulated gamma rhythms, and demonstrating electric field effects on those rhythms. First, theta-modulated gamma rhythms require specific inhibitory connectivity. In one configuration, GABAergic axo-dendritic feedback on pyramidal cells is only effective in proximal but not distal layers. An alternative configuration requires two distinct perisomatic interneuron classes, one exclusively receiving excitatory contacts, the other additionally targeted by inhibition. These observations suggest novel roles for particular classes of oriens and basket cells. The second major finding is that subthreshold electric fields robustly alter the balance between different rhythms. Independent of network configuration, positive electric fields decrease, while negative fields increase the theta/gamma ratio. Moreover, electric fields differentially affect average theta frequency depending on specific synaptic connectivity. These results support the testable prediction that subthreshold electric fields can alter hippocampal rhythms, suggesting new approaches to explore their cognitive functions and underlying circuitry.
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影响因子：
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通讯作者：
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作者：
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通讯作者：
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