Extremely low-frequency magnetic field is widely used as a noninvasive stimulation method in clinical practice and basic research. Electrical field induced from magnetic pulse can decrease or increase neuronal electri...Extremely low-frequency magnetic field is widely used as a noninvasive stimulation method in clinical practice and basic research. Electrical field induced from magnetic pulse can decrease or increase neuronal electrical activity. However, the cellular mechanism underlying the effects of magnetic field is not clear from experimental data. Recent studies have demonstrated that "non-neuronal" cells, especially astrocytes, may be the potential effector for transcranial magnetic stimulation(TMS). In the present study, we implemented a neural–astrocyte microcircuit computational model based on hippocampal architecture to investigate the biological effects of different magnetic field frequencies on cells. The purpose of the present study is to elucidate the main influencing factors of MS to allow a better understanding of its mechanisms.Our model reproduced the basic characteristics of the neuron and astrocyte response to different magnetic stimulation. The results predict that interneurons with lower firing thresholds were more active in magnetic fields by contrast to pyramidal neurons. And the synaptic coupling strength between the connected neurons may be one of the critical factor to affect the effect of magnetic field on cells. In addition, the simulations show that astrocytes can decrease or increase slow inward currents(SICs) to finely tune neuronal excitation, which suggests their key role in excitatory–inhibitory balance. The interaction between neurons and astrocytes may represent a novel target for effective therapeutic strategies involving magnetic stimulation.展开更多
当大规模开放式网络课程MOOC(Massive Open Online Courses)在美国快速发展之际,其在我国也受到了前所未有的关注。文章提出了推进MOOC发展的关键视角:学习者、资源、平台、学校。文章并从这四个方面整合分析了我国MOOC发展存在的以下问...当大规模开放式网络课程MOOC(Massive Open Online Courses)在美国快速发展之际,其在我国也受到了前所未有的关注。文章提出了推进MOOC发展的关键视角:学习者、资源、平台、学校。文章并从这四个方面整合分析了我国MOOC发展存在的以下问题:网络学习者情感缺失的通病仍然存在;学生流失率高;兴趣激发与作弊阻止难以甄别;资源上MOOC教学模式的实质性创新有待加强,课程存在局限性;平台上存在跨国文化的学习障碍,发展同质化;学校发展MOOC不均衡,校际竞争激烈等。文章并就此提出相应的推进策略,包括创建实体化学习群体,加强学习支持服务、适度增加"学习成本",完善评价监督机制;创新MOOC课程教学设计,加强MOOC课程准入和退出机制;平台增加语言选择功能和跨文化背景介绍,建立平台标准;以及构建校际联盟等。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 61673158)the Youth Talent Support Program of Hebei Province,China(Grant No. BJ2019044)。
文摘Extremely low-frequency magnetic field is widely used as a noninvasive stimulation method in clinical practice and basic research. Electrical field induced from magnetic pulse can decrease or increase neuronal electrical activity. However, the cellular mechanism underlying the effects of magnetic field is not clear from experimental data. Recent studies have demonstrated that "non-neuronal" cells, especially astrocytes, may be the potential effector for transcranial magnetic stimulation(TMS). In the present study, we implemented a neural–astrocyte microcircuit computational model based on hippocampal architecture to investigate the biological effects of different magnetic field frequencies on cells. The purpose of the present study is to elucidate the main influencing factors of MS to allow a better understanding of its mechanisms.Our model reproduced the basic characteristics of the neuron and astrocyte response to different magnetic stimulation. The results predict that interneurons with lower firing thresholds were more active in magnetic fields by contrast to pyramidal neurons. And the synaptic coupling strength between the connected neurons may be one of the critical factor to affect the effect of magnetic field on cells. In addition, the simulations show that astrocytes can decrease or increase slow inward currents(SICs) to finely tune neuronal excitation, which suggests their key role in excitatory–inhibitory balance. The interaction between neurons and astrocytes may represent a novel target for effective therapeutic strategies involving magnetic stimulation.
文摘当大规模开放式网络课程MOOC(Massive Open Online Courses)在美国快速发展之际,其在我国也受到了前所未有的关注。文章提出了推进MOOC发展的关键视角:学习者、资源、平台、学校。文章并从这四个方面整合分析了我国MOOC发展存在的以下问题:网络学习者情感缺失的通病仍然存在;学生流失率高;兴趣激发与作弊阻止难以甄别;资源上MOOC教学模式的实质性创新有待加强,课程存在局限性;平台上存在跨国文化的学习障碍,发展同质化;学校发展MOOC不均衡,校际竞争激烈等。文章并就此提出相应的推进策略,包括创建实体化学习群体,加强学习支持服务、适度增加"学习成本",完善评价监督机制;创新MOOC课程教学设计,加强MOOC课程准入和退出机制;平台增加语言选择功能和跨文化背景介绍,建立平台标准;以及构建校际联盟等。
