Modulation of a Single Neuron Has State-Dependent Actions on Circuit Dynamics(,).
Modulation of a Single Neuron Has State-Dependent Actions on Circuit Dynamics(,).
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DOI：
10.1523/eneuro.0009-14.2014
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发表时间：
2014-11
期刊：
影响因子：
3.4
通讯作者：
Marder E
中科院分区：
文献类型：
--
作者：
Gutierrez GJ;Marder E
我们使用计算模型来研究单个神经元的调制可以改变整个电路的动态的情况。我们表明，在某些情况下，电路的行为对单个中枢神经元的神经调节具有鲁棒性，而在其他情况下，单个神经元的相同神经调节作用可以产生多种电路结果。对回路中单个神经元的神经调节可以对回路的输出几乎没有影响，或者可以改变回路内的活动模式。这取决于给定相同电路结构的突触参数，因此说明了单独用于确定电路行为的连接体的不足。单个神经元的神经调节何时会影响整个网络的输出？我们构建了一个五细胞电路，其中一个神经元位于电路的中心，其余的神经元形成两个不同的振荡子网络。所有的神经元都被建模为修改后的Morris-Lecar模型，除了钙（Ca），钾（K）和泄漏电导外，还具有超极化激活电导（K）。我们确定了不同的钙，钾，和钙对一个单一的神经元振荡器的频率，振幅和占空比的影响。当K和h电导高且Ca中等时，单个神经元的频率最高，而在传统的Morris-Lecar模型中，当K和Ca都高时，频率最高。我们随机抽取参数空间，找到143个频率几乎相同但最大电导、占空比和突发幅度不同的中枢振荡器，然后将这些中枢神经元中的每一个嵌入到具有不同突触参数的网络中。对于一组网络参数，无论中枢神经元的潜在电导如何，电路行为几乎是相同的。对于一组不同的网络参数，电路行为随中枢神经元的最大电导而变化。这表明，当网络处于一种状态时，单个目标神经元的神经调节可能会显著改变整个网络的性能，但当电路处于不同状态时几乎没有影响。
We use computational models to examine the circumstances under which modulation of a single neuron can alter the dynamics of an entire circuit. We show that under some circumstances, the circuit's behavior is robust to the neuromodulation of a single hub neuron, while under other circumstances the same neuromodulatory action of a single neuron can produce a large variety of circuit outcomes. Neuromodulation of a single neuron in a circuit can either have little to no effect on the output of the circuit, or it can change the pattern of activity within that circuit. This is dependent on the synaptic parameters given the same circuit architecture, thus illustrating the insufficiency of the connectome alone for determining circuit behavior. When does neuromodulation of a single neuron influence the output of the entire network? We constructed a five-cell circuit in which a neuron is at the center of the circuit and the remaining neurons form two distinct oscillatory subnetworks. All neurons were modeled as modified Morris−Lecar models with a hyperpolarization-activated conductance (ḡh) in addition to calcium (ḡCa), potassium (ḡK), and leak conductances. We determined the effects of varying ḡCa, ḡK, and ḡh on the frequency, amplitude, and duty cycle of a single neuron oscillator. The frequency of the single neuron was highest when the ḡK and ḡh conductances were high and ḡCa was moderate whereas, in the traditional Morris−Lecar model, the highest frequencies occur when both ḡK and ḡCa are high. We randomly sampled parameter space to find 143 hub oscillators with nearly identical frequencies but with disparate maximal conductance, duty cycles, and burst amplitudes, and then embedded each of these hub neurons into networks with different sets of synaptic parameters. For one set of network parameters, circuit behavior was virtually identical regardless of the underlying conductances of the hub neuron. For a different set of network parameters, circuit behavior varied with the maximal conductances of the hub neuron. This demonstrates that neuromodulation of a single target neuron may dramatically alter the performance of an entire network when the network is in one state, but have almost no effect when the circuit is in a different state.