皮层神经元内在特性对神经信号编码稳态的调控作用

发布时间：2018-04-13 09:35

本文选题：电生理 + 药理学　；参考：《沈阳药科大学》2006年博士论文

【摘要】：大脑高级中枢通过编码神经信号语言来控制人的运动、情感、意识和认知等行为。神经信号编码调控行为活动与神经元本身内在特性、突触传递特性和整个神经网络特性有关。要破解神经信号和行为的对应关系，就先要了解神经信号语言。神经信号语言主要涵盖以下信息：神经信号的编码模式即发放形式(适应性群集动作电位和紧张型群集动作电位)，动作电位的编码频率(或称为信息容量)和动作电位的发放稳定性(即信息的忠实性)。无论是动作电位的发放模式、发放频率和发放稳定性都受到突触动力学和神经元编码动作电位的内在特性(阈电位水平、不应期和后超极化等)的限制和调控。所以定量描述神经元动作电位的内在特性和突触动力学特性对于我们解释神经信号的行为控制是至关重要的。我们运用电生理(如全细胞膜片钳和细胞贴覆式单通道技术)和药理学方法研究了感觉运动皮层锥体神经元、中间神经元和小脑浦肯野细胞的内在特性，即阈电位水平、不应期和后超极化，对神经元群集发放动作电位的发放容量和发放精确性的影响及基于Na~+通道的可能机制。结果表明：三种神经元的阈电位水平、不应期和后超极化等这些内在特性不尽相同，但是都与群集动作电位的发放容量和发放位相精确性成线性相关性。外来兴奋性输入和抑制性后超极化可以调控神经元动作电位的编码特性，并且是通过神经元本身编码动作电位的内在特性起作用。此外，细胞内Ca~(2+)信号与神经细胞兴奋性、编码精确性和自身稳态调控有关。通过对电压门控Na~+通道的单通道记录，我们发现电压门控Na~+通道的通道特性与全细胞模式下动作电位发放内在特性吻合。提示，神经元编码动作电位的内在特性是直接受电压门控Na~+通道调控的。此外，兴奋性输入强度和超极化可以影响电压门控Na~+通道的激活和再活化，，表明突触输入可塑性可以诱导电压门控Na~+通道的可塑性，从而引起神经元编码动作电位内在特性的可塑性。并且电压门控Na~+通道介导的内在特性(阈电压和不应期)对中枢神经元群集动作电位的编码调控作用并不依赖于K~+通道的作用。我们的实验结果为阐明神经元信号精确分析计算的细胞分子机制提供了一定的理论依据。
[Abstract]:The advanced brain centers control human motor, emotional, conscious and cognitive behaviors by coding neural signal language.Neural signal coding regulates behavioral activity and is related to the intrinsic characteristics of neurons, synaptic transmission characteristics and the characteristics of the neural network as a whole.To decipher the corresponding relation between neural signal and behavior, we must first understand the language of nerve signal.The neural signal language mainly covers the following information: the coding mode of the neural signal is the form of issuance (adaptive cluster action potential and tension cluster action potential), the encoding frequency of the action potential (or information capacity) and the movement of the action potential.The stability of the distribution of potential (that is, the fidelity of the information).Both the mode, frequency and stability of release of action potential are restricted and regulated by the intrinsic characteristics of synaptic dynamics and neuron encoded action potential (threshold potential level, refractory period and post hyperpolarization, etc.).Therefore, quantitative description of the intrinsic characteristics of action potential and synaptic dynamics of neurons is essential for us to explain the behavioral control of neural signals.We studied the intrinsic characteristics of sensory motor cortex pyramidal neurons, intermediate neurons and cerebellar Purkinje cells using electrophysiology (such as whole-cell patch clamp and cell-attached single-channel technique) and pharmacological methods.The results show that the threshold potential level, refractory period and post hyperpolarization of the three kinds of neurons are different, but they are linearly correlated with the discharge capacity and the accuracy of the firing phase of the cluster action potential.Extraneous excitatory input and suppressive post-hyperpolarization can regulate the encoding characteristics of neuronal action potential and play an important role through the intrinsic characteristics of the neuron itself encoding action potential.In addition, intracellular Ca~(2 signals are related to neuronal excitability, coding accuracy and homeostasis.By recording the single channel of voltage-gated Na ~ channel, we find that the channel characteristics of voltage-gated Na ~ + channel are consistent with the intrinsic characteristics of action potential release in whole-cell mode.It is suggested that the intrinsic characteristics of neuron encoded action potential are directly regulated by voltage-gated Na ~ channels.In addition, excitatory input intensity and hyperpolarization can affect the activation and reactivation of voltage-gated Na ~ channels, indicating that synaptic input plasticity can induce the plasticity of voltage-gated Na ~ channels.Therefore, the plasticity of the intrinsic characteristics of the neuron encoded action potential is induced.Moreover, the coding and regulating effect of voltage-gated Na ~ channel mediated intrinsic characteristics (threshold voltage and refractory period) on the action potential of CNS is independent of the action of K ~ channel.Our experimental results provide a theoretical basis for elucidating the cellular molecular mechanism of neuron signal analysis and calculation.
【学位授予单位】：沈阳药科大学
【学位级别】：博士
【学位授予年份】：2006
【分类号】：R33

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