Evidences show that electric fields(EFs)induced by the magnetic stimulation could modulates brain activities by regulating the excitability of GABAergic interneuron.However,it is still unclear how and why the EF-induc...Evidences show that electric fields(EFs)induced by the magnetic stimulation could modulates brain activities by regulating the excitability of GABAergic interneuron.However,it is still unclear how and why the EF-induced polarization affects the interneuron response as the interneuron receives NMDA synaptic inputs.Considering the key role of NMDA receptor-mediated supralinear dendritic integration in neuronal computations,we suppose that the applied EFs could functionally modulate interneurons’response via regulating dendritic integration.At first,we build a simplified multi-dendritic circuit model with inhomogeneous extracellular potentials,which characterizes the relationship among EF-induced spatial polarizations,dendritic integration,and somatic output.By performing model-based singular perturbation analysis,it is found that the equilibrium point of fast subsystem can be used to asymptotically depict the subthreshold input–output(sI/O)relationship of dendritic integration.It predicted that EF-induced strong depolarizations on the distal dendrites reduce the dendritic saturation output by reducing driving force of synaptic input,and it shifts the steep change of sI/O curve left by reducing stimulation threshold of triggering NMDA spike.Also,the EF modulation prefers the global dendritic integration with asymmetric scatter distribution of NMDA synapses.Furthermore,we identify the respective contribution of EF-regulated dendritic integration and EF-induced somatic polarization to an action potential generation and find that they have an antagonistic effect on AP generation due to the varied NMDA spike threshold under EF stimulation.展开更多
A track structure model has been applied to calculate the relative thermoluminescent efficiency of TLD- 100 irradiated with energetic heavy ions. In earlier work we proposed that the response of TLD- 100 to γ-ray ari...A track structure model has been applied to calculate the relative thermoluminescent efficiency of TLD- 100 irradiated with energetic heavy ions. In earlier work we proposed that the response of TLD- 100 to γ-ray arises from a combination of 1- hit and 2- hit trap structures. The supralinear (2- hit) response is now known to diminish with a decrease in the energy of incident electrons. Since the delta rays of slow particles are of low energy, diminishing with a reduction in ion speed, we calculate the response to slow heavy ions by track theory as due to the 1- hit targets alone and obtain good agreement between theory and experiment. The branching of the experimental curves is principally caused by the kinematic limit in delta ray production for ions approaching the end of their range, an effect which is called "thidown" when seen in the tracks of heavy ions approaching the end of their range in electron sensitive nuclear emulsion.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.62171312)the Tianjin Municipal Education Commission Scientific Research Project,China(Grant No.2020KJ114).
文摘Evidences show that electric fields(EFs)induced by the magnetic stimulation could modulates brain activities by regulating the excitability of GABAergic interneuron.However,it is still unclear how and why the EF-induced polarization affects the interneuron response as the interneuron receives NMDA synaptic inputs.Considering the key role of NMDA receptor-mediated supralinear dendritic integration in neuronal computations,we suppose that the applied EFs could functionally modulate interneurons’response via regulating dendritic integration.At first,we build a simplified multi-dendritic circuit model with inhomogeneous extracellular potentials,which characterizes the relationship among EF-induced spatial polarizations,dendritic integration,and somatic output.By performing model-based singular perturbation analysis,it is found that the equilibrium point of fast subsystem can be used to asymptotically depict the subthreshold input–output(sI/O)relationship of dendritic integration.It predicted that EF-induced strong depolarizations on the distal dendrites reduce the dendritic saturation output by reducing driving force of synaptic input,and it shifts the steep change of sI/O curve left by reducing stimulation threshold of triggering NMDA spike.Also,the EF modulation prefers the global dendritic integration with asymmetric scatter distribution of NMDA synapses.Furthermore,we identify the respective contribution of EF-regulated dendritic integration and EF-induced somatic polarization to an action potential generation and find that they have an antagonistic effect on AP generation due to the varied NMDA spike threshold under EF stimulation.
文摘A track structure model has been applied to calculate the relative thermoluminescent efficiency of TLD- 100 irradiated with energetic heavy ions. In earlier work we proposed that the response of TLD- 100 to γ-ray arises from a combination of 1- hit and 2- hit trap structures. The supralinear (2- hit) response is now known to diminish with a decrease in the energy of incident electrons. Since the delta rays of slow particles are of low energy, diminishing with a reduction in ion speed, we calculate the response to slow heavy ions by track theory as due to the 1- hit targets alone and obtain good agreement between theory and experiment. The branching of the experimental curves is principally caused by the kinematic limit in delta ray production for ions approaching the end of their range, an effect which is called "thidown" when seen in the tracks of heavy ions approaching the end of their range in electron sensitive nuclear emulsion.
