Neuroscience-based Realistic Simulation Of The Neuron

Based on neuroscience and adequate experimental data, neuron-simulating techniques enable efficient modeling and simulation of neuronal morphologies, physical and biochemical changes, and interaction among neurons in the neural network. Although systematic researches on such techniques began only about ten years ago, significant achievements have been made in them since then. There are now various kinds of such techniques, each with its features and advantages. With the continuous development of computer technology, particularly of technology for visualization, requirements for the simulation results in terms of realistic descriptiveness, precision, lifelikeness and vividness are becoming more and more challenging, and therefore those for the techniques themselves in terms of structural soundness and graphic descriptiveness are becoming higher and higher.This dissertation, based on comprehensive survey of the existent neuron-simulating systems and techniques and detailed analysis of the major ones, presents and illustrates with examples a set of neuroscience-based neuron-simulating systems, which can generate realistic simulation results, and can be respectively applied to the morphological simulation of the dendrite, the animatedly descriptive simulation of the whole process of axon guidance, and the simulation of diffusion-reaction of nitric oxide (NO) in the neuron. The author has done beneficial and explorative researches on the following:1. Realistic morphological simulation of the dendrite based on modularized L-systems.The dendrite morphology is closely related to the functions of the neuron and even of the whole nervous system. This dissertation presents a set of methodologies for three-dimensional realistic morphological simulation of the dendrite, which are both graphically descriptive and user-friendly. It has particularly established a modularized dendrite-simulating system, any of whose modules can be used elsewhere, and which accords with L-systems' grammar; this system greatly facilitates the modeling andsimulation because of its modularization and other features such as parameterization. No additional programming is required in the simulation. The simulation results are reliable as the parameters have been derived from analysis, abstraction and summarization of sufficient experimental data. These results conform to real dendrites to a great degree, as can be known by comparison. The results can be converted into common computational neuron model formats such as Genesis and Neuron, so that they can be used in simulation of physiological functions of the neuron.2. Application of open-L-systems to animatedly descriptive simulation of axon guidance.In order that the whole process of axon guidance can be simulated efficiently and precisely, this dissertation presents and illustrates with examples a system for animatedly descriptive simulation of the process, which is based on open L-systems. This system enables the simulation through two concurrent processes — the process of the extracellular environment and that of the growing neuron having its axon guided towards the target area by specific mechanisms. These two processes communicate and interact with each other by means of communication modules. It is by changing the values of the parameters in the communication modules that the extracellular environment process affects the axon's development and elongation. A suitable open L-system is used to describe the axon's development and elongation in its environmental context. The simulation results displayed on the computer screen, vivid and animated, realistically describes the whole process of axon guidance.3. Constructing a realistic model of NO diffusion-reaction in the neuron.NO as a neurotransmitter has remarkable effect on the nervous system. At present there is no effective technique or method for detecting the activities of NO in vivo in real time, whereas modeling and simulation of the diffusion and reaction of NO as a neurotransmitter helps deepen the understanding of it. This dissertati...