Biological and Physiological Engineering Study on Global Regulatory Mechanisms of The Brain as A Complex System

作为复杂系统的代表，脑的全局调节机制是从生物学和生理工程学的角度来研究的。主要研究结果如下：1.研究了外侧膝状体（LGN）和皮层18区、6区神经元活动在睡眠周期中的动态变化。LGN神经元特征性地表现出爆发活动，其被证实表现出从白色功率谱密度（PSD）（慢波睡眠：SWS）到1/f PSD（快眼动睡眠：REM）的神经元动力学转变。皮层神经元也表现出与迄今为止所研究的神经元相同的动力学转变。这些结果支持了我们的假设，即大脑处理系统中的神经元在睡眠周期中普遍表现出相关的动力学转换。2.高精度液相色谱柱的长度、介质的组成和氧化还原电位是影响睡眠周期的重要因素。 ...更多信息 e优化进行血清素浓度的微透析，在大脑中的调节系统的神经递质，这使我们能够研究血清素浓度和神经元动力学之间的关系。因此，浓度可以测量到fmol的数量级。通过这种新的方法，测量了LGN（wake>SWS>REM）中5-羟色胺浓度的睡眠-觉醒依赖性变化。3.基于神经网络模型，研究了LGN中神经元动力学转换的机制，发现网络内部神经元输入与外部神经元输入之间的平衡是导致这种现象的关键。也就是说，对于1/f波动，内部输入必须主导外部输入，而对于呈现白色PSD的随机活动，内部输入必须满足相反的关系，这表明调节系统对相关动力学转变的影响是多样的。此外，与REM睡眠相关的神经网络亚稳定性可能是梦的生理基础，这为理解梦与大脑高级功能的关系提供了新的信息。少

As a representative of a complex system, global regulatory mechanisms of the brain are investigated from the biological and physiological engineering point of view. The research results are summarizedas follows.1.Dynamics tratnsitions of neuronal activities during sleep cycles are studied in the lateral geniculate nucleus (LGN) and the cortical areas 18 and 6. The LGN neurons characteristically show bursting activities, which are confirmed to exhibit the neuronal dynamics transition from the white power spectral density (PSD) (slow wave sleep : SWS) to the 1/f PSD (rapid eye movement sleep : REM). The cortical neurons also exhibit the same dynamics transition as the neurons studied so far. These results support our hypothesis that neurons in the processing systems of the brain commonly exhibit the concerned dynamics transitions during sleep cycles.2.The length of the column, the compositions of medium, and the oxidation-reduction potential of the high precision liquid chromatography ar … More e optimized to carry out a microdialysis of serotonin concentration, a neurotransmitter of the regulatory system in the brain, which enables us to study the relationship between the serotonin concentration and the neuronal dynamics. As a result, concentration can be measured down to an order of fmol. By this novel method, sleep-wake-dependent variations of the serotonin concentration are measured in LGN (wake>SWS>REM).3.Mechanisms underlying the neuronal dynamics transition are investigated based on the neural network model, which shows that the balance between the inputs from the neurons within the network and those from the external neurons is essential for this phenomenon. That is, for the 1/f fluctuations the internal inputs are required to dominate the external, and the opposite relation should be satisfied for the random activities exhibiting the white PSD.This suggests that the regulatory system exerts diverse effects on the concerned dynamics transition. In addition, the metastability of the neural network relates to REM sleep might be a physiological substrate of dreaming, which provides a novel information for understanding the relationship between dreaming and higher-order brain functions. Less