| Transcranial pulsed current stimulation(t PCS)adopts physical non-invasive brain stimulation technology.Its essence is to act on the cerebral cortex with a fixed frequency of weak current pulse through the anode and cathode of the electrodes.The affected brain areas selectively activates endorphins and other neurotransmitters to release into blood and cerebrospinal fluid,which can promote the changes in the level of relevant hormones in the cerebral cortex,regulates the activity of cortical neurons and has broad application value in the fields of human function recovery and treatment of depression pathology.Although significant results have been achieved in the research of direct current transcranial electrical stimulation in China,there is still a large gap between the research of pulsed transcranial electrical stimulation and its related control with foreign countries.At present,the domestic transcranial pulsed electrical stimulation devices are in the exploration and research stage,which have the disadvantages of single function and difficulty of carrying.To address this situation,the software and hardware structure of transcranial pulsed electrical stimulator is studied in depth to realize the upper computer APP to control the output of weak current pulses while making it portable,and at the same time reduce the cost of equipment development and application.Firstly,combining with the current relevant transcranial pulse electrical stimulation research literature,the functional mechanism of transcranial pulse electrical stimulator was analyzed,as well as the analysis of current output intensity,pulse frequency,electrode shape,action position,action spacing,wearing appearance and structure.In addition,the technical scheme of each parameter has been formulated,and the scheme was verified in detail.Next,the current pulse control and power supply circuits are studied,and a circuit design scheme based on STM32 microprocessor is proposed.The key hardware circuit board design and software design of bipolar milliamp current output are carried out to achieve adjustable pulse frequency and current intensity specifications.In addition,in order to achieve the constant current pulse characteristics,it is proposed to incorporate a fuzzy PID control algorithm to improve the response speed of the constant current output of the device.Finally,the output electrical parameters of the device developed in this project are tested and animal experimental research is carried out.Different resistances are used to simulate human cranial resistance for functional testing,and experimental models are established and animal experiments are implemented to analyze the changes of endorphins,5-hydroxytryptamine,cortisol and other related neurotransmitters in the brain area of rats after fatigue electrical stimulation,and to explore the relationship between the output electrical parameters of transcranial pulsed electrical stimulation and the principle of action.The results show that the display and control software of the upper computer APP runs stably during the test.Moreover,the error of the output frequency measured by the instrument is less than 0.5%,and the maximum error of the output current is 1.67%,which satisfied the output technical index of the transcranial pulse electrical stimulator development.The analysis of the neurotransmitter content in the blood of each group of the experimental rats verified that the transcranial pulse electrical stimulator has a regulatory effect on the secretion of neurotransmitters in the brain area of rats. |
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