| More and more countries in the world pay attention to the related research of brain science.In the "14th Five-Year Plan",China’s brain science and brain-like research will focus on five key areas of in-depth research,including the interpretation of brain cognitive principles,mapping of brain mesoscopic nerve connections,and the mechanism and intervention of major brain diseases.The cellular level of neuroscience constitutes the cornerstone of brain science,but the mechanism of neural signal transmission is still uncertain.The physical process of Na+channel opening in nerve fibers is essential for understanding the nature of neural signals and revealing the mechanism of signal generation and transmission in nerves.Cable model,electromechanical soliton model,neural waveguide model,quantum communication model and quantum constrained superfluid model have been proposed to study neural signal transmission.The difference between them lies in the interpretation of the physical properties and transmission pathways of neural signals.Electric current,mechanical wave and electromagnetic signal have all become the entry Angle for scholars to study neural signal transmission mechanism.Among them,cable model and electromechanical soliton model can not explain the jumping conduction of the upper nerve signal of the myelinated nerve fiber,while the neural waveguide model can explain the jumping conduction phenomenon of the nerve signal,which is the most concerned neural signal transmission.However,the neural waveguide model has limited the further development of neural waveguide model and its application in the study of neural signal transmission mechanism.Therefore,based on the neural waveguide model,we carry out a series of studies on the generation and transmission mechanism of neural electromagnetic signals from the real generation and transmission process of neural signals.Firstly,a simplified nano-bionic Na+voltage-gated channel model was established to simulate the complete physical process of neural electromagnetic signals generated by Na+transmembrane flow after opening a single ion channel under the action of multiple physical fields such as electrostatic field and material transport field.The results show that due to the difference of Na+concentration on both sides of the membrane under dynamic equilibrium,Na+flux can reach a stable state within about 10 ns after opening the channel,resulting in two frequency band electromagnetic signals(f1≈105 Hz,f2≈108 Hz)generated during the whole opening process of Na+channel.After characterizing the spectrum and transmission characteristics of the two electromagnetic signals,Only the low frequency signal f1≈105 Hz can be transmitted over a long distance in the neural waveguide.Therefore,the low frequency transmembrane electric field f1≈105 Hz is regarded as the physical quantity transmitted in the waveguide-like lipid medium layer and triggering the adjacent voltage-gated channel.In addition,we also study the influencing factors of Na+flux transport.It is concluded that the effect of Na+concentration gradient on Na+transport rate is greater than the initial transmembrane potential.Introducing a surface negative charge to the upper third of the channel can increase the transmembrane Na+current and hinder the Effect of Cl-.The simulation study not only helps us to clarify the generation process and spectral characteristics of neural electromagnetic signals,but also helps us to better understand the opening mechanism of voltage-gated ion channels.Clear after neural signal process and the specific spectrum characteristics,this paper introduces the neural signal relay time of electromagnetism,found that neural signal transmission speed(V)and the effective transmission distance(S)that there was a linear relationship between the late for electromagnetic signal transmission characteristics the results of experiment provides the feasible bridge.In this paper,a simulation model of myelinated nerve fibers is established to study the transmission law of neural electromagnetic signals in the neural fibers obtained in the bionic Na+voltage gated channel model,and to observe the relationship between the thickness of axons and myelin sheath and the effective transmission distance.The results show that the effective distance of nerve signal transmission has a logarithmic relationship with axon and a linear relationship with myelin sheath thickness,which is consistent with a large number of reported biological experiments.This conclusion provides strong support for exploring neural signal transmission law at the simulation level.The two simulation models established in this study respectively simulate the generation and transmission process of neural electromagnetic signals,observe the physical process after the ion channel is opened,and deeply explore the factors affecting the neural signal transmission effect.Although current models are relatively simple,these findings have important implications for understanding the generation and transmission of neural signals in the nervous system and brain.Further research can be carried out by improving these two simulation models in the future. |
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