内生场对神经集群节律影响的研究

发布时间：2018-06-30 06:14

本文选题：内生场 + 海马核团　；参考：《天津大学》2014年硕士论文

【摘要】：最近研究表明,在胞外空间产生的电势波动即内生电场,不仅能够作为神经活动的观察窗口,还能够作为神经元之间的非突触耦合方式反馈回细胞膜上,进而影响网络的动态行为。例如,低钙状态下胞外阻抗增加,内生场增强,这有可能是产生癫痫样放电的主要原因,而且相对强度很低的电场的效应也可以通过网络之间的交互得到放大。海马是大脑有关学习和记忆的重要组织,因此本文以海马核团为研究对象,研究内生场对海马核团节律的影响。本文根据不同的研究目的建立了两种海马核团模型,首先以海马椎体神经元为研究对象,以平均场模型简化内生场,建立了神经元之间化学突触耦合与电突触耦合同时存在且形成小世界连接、内生场全局耦合的海马核团,研究了内生场对海马核团检测弱信号的影响。研究发现作为神经元之间一种普遍存在且非常重要的非突触耦合方式,内生场耦合能够促进混杂耦合集群对于外部弱信号的检测,并且这种促进作用随着内生场耦合强度的增大而增强。本文从集群放电的角度分析了随机共振传递信息的机制,并且发现内生场耦合能够在没有噪声和外界刺激的情况下独立引发放电,且这种耦合能够在集群传递弱信号的过程中作为类似于噪声的驱动源,在没有噪声的情况下驱动集群传递弱信号,而这种现象在化学突触和电突触中不会出现。其次以海马椎体神经元(兴奋性神经元)与中间神经元(抑制性神经元)为研究对象,以外加电场模拟内生场,建立了兴奋性与抑制性神经元共同存在的海马核团,研究不同幅值不同频率的外电场通过内生场耦合对神经元电活动的影响。发现弱外电场对于网络节律具有调制作用,尤其是在施加与原网络具有相同频率的正弦信号时,网络出现了次谐波振荡。本文研究了内生场对集群传递和检测弱信号的作用,并分析了其作用机制,同时研究了不同直流电场和交流电场下海马核团节律的变化。对揭示外界电磁场对大脑神经元的作用机制有重大意义,同时也为癫痫的电磁刺激治疗提供了理论依据。
[Abstract]:Recent studies have shown that the potential fluctuations generated in the extracellular space, the endogenous electric field, can not only serve as the observation window of neural activity, but also can be fed back to the cell membrane as a non-synaptic coupling between neurons. Then the dynamic behavior of the network is affected. For example, the increase of extracellular impedance and the enhancement of endogenous field in low calcium state may be the main cause of epileptoid discharge, and the effect of electric field with low relative intensity can be amplified by interaction between networks. Hippocampus is an important organization of learning and memory in the brain. Therefore, the effect of endogenous field on the rhythm of hippocampal nucleus is studied in this paper. In this paper, two kinds of hippocampal nucleus models were established according to different research purposes. Firstly, the hippocampal neurons were taken as the research objects, and the mean field model was used to simplify the endogenous field. The hippocampal nuclei with small world connections and global coupling of endogenous fields were established, and the effects of endogenous fields on the weak signal detection of hippocampal nuclei were studied. It is found that as a common and important non-synaptic coupling between neurons, endogenous field coupling can promote the detection of external weak signals in hybrid coupled clusters. Moreover, the effect of this kind of promotion increases with the increase of the coupling strength of the endogenetic field. In this paper, the mechanism of stochastic resonance transmission information is analyzed from the point of view of cluster discharge, and it is found that endogenous field coupling can trigger discharge independently without noise and external stimulation. And this coupling can be used as a noise-like driving source in the process of transmitting weak signals in clusters, and it can drive the transmission of weak signals in clusters without noise, but this phenomenon does not occur in chemical and electrical synapses. Secondly, the neurons (excitatory neurons) and intermediate neurons (inhibitory neurons) of hippocampal vertebrae were used to simulate the endogenetic field, and the hippocampal nuclei of excitatory and inhibitory neurons were established. The effect of external electric field with different amplitudes and different frequencies on the electrical activity of neurons through endogenous field coupling was studied. It is found that the weak external electric field modulates the rhythm of the network, especially when the sinusoidal signal with the same frequency as the original network is applied, the sub-harmonic oscillation occurs in the network. In this paper, the effects of endogenetic fields on the transmission and detection of weak signals in clusters are studied, and the mechanism of action is analyzed. At the same time, the rhythm of hippocampal nuclei under different DC and AC fields is studied. It is of great significance to reveal the mechanism of external electromagnetic field acting on brain neurons, and it also provides a theoretical basis for the treatment of epilepsy by electromagnetic stimulation.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R338

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