主动训练诱导运动皮层长时程增强的神经-血氧动态影响机制的研究

The functional reorganization of central nervous system through active physical training is believed to be essential for motor rehabilitation; meanwhile long-term potentiation (LTP), the long-lasting strengthen of synapses, has been recognized to be the basis for neural plasticity within motor cortex. However, the mechanism that how motor training induced LTP during rehabilitation still remains to be further elucidated. It is well documented that neural activity and cerebral blood flow (CBF) were tightly coupling to each other, which was usually referred as neurovascular coupling; therefore, the CBF and blood oxygen metabolism should also affect the neural structural and functional reorganization during motor rehabilitation. According to above, the applicant propose that the dynamic mechanism of neuronal activity and blood oxygen metabolism evoked by active motor behavior may be a potentially important indicator to characterize the effects of how active motor training improve motor functions. Electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) techniques will be employed, so that both the signals corresponding to neuronal activity and blood oxygen metabolism can be simultaneously recorded for analysis. The study intent to build a model quantitatively investigating the dynamic response of neuronal activity and blood oxygen metabolism corresponding to motor behaviors, and also the relationship to motor tasks. Motor tasks will be carefully designed upon different training load, to characterize relative impact on LTP and blood oxygen metabolism. Furthermore, the adaption of relationship between neuronal activity and blood oxygen metabolism corresponding to motor cortex plasticity will be evaluated. By studying the dynamic mechanism and impact of blood oxygen metabolism upon brain plasticity induced by active motor training, this project proposes to provide helpful evidences to optimize the neurorehabilitation therapy for motor function.

主动训练诱导中枢神经功能重组对运动康复至关重要，突触长时程增强（LTP）被认为在运动皮层神经可塑性变化中发挥着关键作用，但康复训练促进LTP的内在机制尚待进一步阐明。大脑的神经-血管耦合使血氧代谢密切影响着神经活动及功能，而运动引起的皮层血氧代谢变化应该调控了运动康复的神经结构和功能重建。申请人认为，自主运动诱发的神经-血氧动态变化是表征主动康复训练增强运动神经功能的重要指标。本课题将结合脑电和功能近红外光谱成像技术，通过检测分析运动皮层的神经活动和血氧代谢参数，探索建立运动诱发神经-血氧动态变化的量化模型，研究运动模式与神经、血氧变化的量效关系；通过不同运动任务，测试分析运动负荷改变对LTP与脑血氧代谢的影响，评估分析运动皮层可塑性改变的神经-血氧响应与调控机制。本课题旨在揭示主动训练诱导运动皮层血氧代谢与其促成的神经功能可塑性变化间的内在联系，探索能促进运动神经康复的主动康复运动模式。

运动康复治疗往往通过大量重复针对性的运动训练诱导大脑功能区产生可塑性改善，以期恢复或部分恢复其运动功能。主动康复训练诱导运动功能区重组是一个长期动态过程，运动负荷、任务及其模式的改变产生的影响不尽相同。本课题旨在初步探究主动运动训练诱导皮层长时程增强的动态激活响应机制，根据研究目的，结合功能近红外光谱成像技术等，本课题搭建运动任务可视化上肢训练实验平台，实现握力、肌电、血氧等多种生理参数信号的连续同步监测，并通过视觉反馈协助被试者调整自身力量输出。实验设计基于上肢抓握运动，以力量输出的强度、时间、频率等多种变量灵活量化任务负荷。纳入健康志愿者，监测并分析运动皮层区对主动运动训练的激活响应，训练过程中皮层相应功能区血氧水平先增强后逐步回落的动态变化趋势，该过程中大脑通过学习和优化选择整合，其激活响应呈现“扩散-归一”模型。脑网络分析显示其激活响应逐渐归一化同时可能伴随着脑功能连接的增强效应，且该效应具有近迁移性，可有效应用于类似任务场景。经颅磁刺激研究进一步揭示，足够时长的重复性运动训练能够诱发长时程增强效应，有效促进下行运动传导通路的兴奋性。课题进一步探究了不同难度任务模式和不同训练序列模式训练的影响，高难度训练任务下大脑更长时间地维持较高激活，训练后被试获得更强的近迁移能力。最后，结合肌电信号特征分析量化肌肉疲劳状态，以抓握力量水平为量化指标，设计根据肌肉疲劳状态变化进行任务负荷调节的自适应训练模式，多种训练模式对照训练结果表明，自适应训练模式能够有效延缓训练产生的肌肉疲劳，提升任务执行精确度，脑网络分析进一步印证自适应训练模式下脑网络效率更高且能更持久地维持良好状态。本课题旨在揭示主动训练诱导皮层功能区产生可塑性变化过程中的血氧代谢机制，探索能优化康复治疗方案和提高康复运动效果的主动运动训练模式，具有重要的意义。