Research On Influence And Mechanism Of Transcranial Alternating Current Stimulation On Motor Imagery Tasks

Transcranial alternating current stimulation is a non-intrusive stimulation technique,which imposes periodical alternating low current on the specific brain area.Due to its capability of adjusting exciting activities in the cortex,it has achieved wide attention from academic circles.Motor imagination is an emerging recovery method for dyskinesia.Researches in recent years pointed out that transcranial direct current stimulation can improve the task capability of motor imagination and promote motor imagination recovery effects.This research conducts an in-depth study of the influence of transcranial alternating current stimulation on the task capability of motor imagination at an attempt to come up with new ways to promote effects of motor imagination therapy.Below is a brief summary of the research content in this paper:(1)Build and improve the research platform featuring transcranial alternating current stimulation combined with EEG: First,develop and make a multi-parameter stimulator and test its output performance;second,put forward methods to eliminate current interfering signals during synchronous EEG and verified the denoising effect;third,come up with methods to remove noises and artifacts of EEG signals of the platform.(2)Clarify the influence of transcranial alternating current stimulation on the task capability of motor imagination: First,analyzed behavioral performance before and after the stimulation based on psychological rotation cognition tasks;second,reveal thatα and β rhythm stimulation can significantly reduce the task response time;third,discover changes of event-related potentials and event related desynchronization based on electophysiological analysis of psychological rotation;(3)Study the influence of transcranial alternating current stimulation on EEG’s frequency-domain characteristics: First,suggest that the alternating current stimulation can improve the α rhythm power in every brain area and reduce the individual α rhythm frequency shift according to analysis of α rhythm frequency stimulation and power spectrum analysis;second,analyze the after-effect duration after stimulation based on power changes of the α rhythm;third,use the nerve cell oscillation model to conduct a simulation research of the neuromechanism which can stimulate and promote the EEG power.(4)Explore the influence of transcranial alternating current stimulation on EEG complexity: First,discover that the stimulation has no significant influence on EEG complexity according to Lempel-Ziv Complexity(LZC)and the approximate entropy analysis of EEG complexity before and after simulation;second,put forward methods to evaluate the after-effect duration based on sliding approximate entropy and discuss analysis results.(5)Study the influence of transcranial alternating current stimulation on the brain network: First,study the influence of the stimulation on the brain network synchronism based on the correlation analysis method,and suggest that the brain network synchronism shows an improvement tendency after stimulation;second use the Complex Network Theory to analyze brain functions before and after stimulation,and preliminary reveal that the stimulation has no significant influence on global parameters and local parameters of the brain functional network.Through this research,the author: 1)clarifies that transcranial alternating current stimulation can improve the task capability of motor imagination;2)reveals that transcranial alternating current has an influence on the EEG frequency domain and complexity,and the brain functional network.Findings of this research can provide some references for application of transcranial alternating current stimulation to motor imagination recovery.