| Neuromodulatiion technologies are fundamental methods for neuroscience researches and clinical applications,transcranial magneto-acousto-electrical stimulation(TMAES)is a new stimulation method in which an ultrasonic wave in a static magnetic field generates an electric field in an area of interest such as in the brain to modulate neuronal activities.TMAES has a better spatial resolution and penetration depth and as a tool for the treatment of neuropsychiatric disorders and the study of brain cognitive science,it has important theoretical significance and practical value for the study of it.Injury or aging of the prefrontal cortex in rats can lead to abnormal activity of the nervous system,which is closely related to the generation of many kinds of neuropsychiatric disorders.Therefore,it is very important to stimulate the prefrontal cortex of rats and study their local field potentials(LFPs).In this paper,the TMAES method and the effects of the method on the LFPs of prefrontal cortex in rats were studied by theoretical analysis,computational simulation,neuron model construction,parameter optimization,signal acquisition and signal analysis of LFPs.This research work mainly includes the following five aspects:1.In this paper we introduced the background of this research,summarized the characteristics and development trend of commonly used neuromodulation techniques at home and abroad,which led to the TMAES and introduced the advantages and development status of this technology.The advantages of TMAES and the function of prefrontal cortex were introduced,which explained the importance of the study on LEPs of prefrontal cortex in rats with TMAES.2.The principle of TMAES was clarified by theoretical analysis and mathematical calculations,which proved that the induced field produced by ultrasound and magnetic fields in nerve tissue can be used to stimulate nerve tissue and the theoretical feasibility of TMAES.In this paper,we established a biological tissue model and then simulated the distribution characteristics of ultrasound and induced electric field in biological tissues,which laid the foundation for TMAES simulation research on neuron model.3.In order to explore the mechanism of TMAES,we analysed the effects of different stimulus parameters on the firing activity of neurons based on the selected H-H neuron model.The simulation results showed that the neuron is sensitive to the change of stimulus parameters,and the change of stimulus parameters can lead to the change of neuron discharge pattern,thus affecting the information coding process in the nervous system.The simulation results provided a theoretical basis for animal experiments with TMAES.4.We constructed a TMAES system,which mainly includes digital signal generator,RF power amplifier,ultrasonic transducer,focusing lens and three-dimensional stereotaxic instrument.We used the well established TMAES system to stimulate the prefrontal cortex of SD rats and recorded the LFPs with multi channel data acquisition system.5.The received signals were segmented and filtered to obtain the ?(11)?(11)?(11)?(11)? signals in different frequency bands.The effects of different stimulation patterns and parameters on the LFPs of prefrontal cortex in rats were investigated by using power percentage.The results showed that the TMAES can effectively stimulate the prefrontal cortex and affect the LFPs of prefrontal cortex in rats.In the LFPs,the ? wave is the main manifestation of the electrical activity when the cerebral cortex is in inhibitory state,the ?(11)? wave are the main manifestation of the electrical activity when the cerebral cortex is in excited state. |
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