The Effects Of RTMS Combined With Motor Training On Motor Function And Brain Network

It was reported that more than the motor activities in 50%of the stroke patients were impaired,and the patients accompanied long-term motor dysfunction.How to recover and reconstruct the limb motor function effectively and reduce the dysfunction has become a problem urgently to be solved.The results of clinical studies showed that the enhanced motor training had positive effects on the recovery of post-stroke movement function,such as constraint induced movement therapy,motor relearning program and so on.However,the motor function outcome is limited induced by those motor training.The cortical excitability was changed after stroke.Repetitive transcranial magnetic stimulation(rTMS)can modulate the neural activities,so lots of researchers began to use rTMS to improve limb function after stroke,and achieved some beneficial results.However,the therapeutic effect of rTMS is limited.Therefore,the researchers began to combine the rTMS with motor training to hope for better motor recovery.The effect of rTMS combined with motor training was assessed through behavior scale.However,the research about brain activities induced by rTMS combined with motor training is still scarce.In this study,the healthy subjects were recruited,and the procedure of rTMS combined with motor training was designed in order to improve the motor function of non-dominant hand.In the experiment,low frequency rTMS stimulated the dominant hemisphere.Three motor training methods,which were familiar to dominant hand,were adopted for training dominant hand.The effects of rTMS combined with motor training on motor function were tested by reaction time finishing Nine-Hole Peg Test,cortical spinal cord excitability obtained by testing motor evoked potentials(MEP)and electroencephalography(EEG).In this study,the single pulse TMS evoked EEG(sTMS-EEG)was used in assessing method.Thus,the artifacts in sTMS-EEG could not be neglected.So this study researched the method to remove artifacts firstly.The conclusion was obtained that the EEG electrode wires should be as far as away from the TMS coil as possible,and the electrodes wires under the TMS coil should be placed along the long axis of TMS coil,in order to obtain the EEG containing TMS induced electromagnetic artifact as small as possible.The residual artifacts,muscle artifacts and blinking artifacts could be removed by time domain and spatial distribution characteristics of independent component.This study found that rTMS combined with motor function significantly improved hand dexterity and increased the excitability of corticospinal tract in non-dominant hemisphere.The functional connectivity and network characteristics of cortices related to motor function in non-dominant hemisphere were changed.The functional connectivity between premotor cortex(FC4)and frontal cortex,the node degree and efficiency of premotor cortex decreased,significantly.The functional connectivity between parietal cortex(CP4)and frontal cortex,the node degree and efficiency of premotor cortex increased,significantly.Motor training also impacted the functional connectivity in alpha frequency band,especially the primary motor cortex(C4)in non-dominant hemisphere and parietal cortex(Pz).However,compare with rTMS combined motor training motor training,the effects of motor training on functional connectivity were weak.The result of sTMS-EEG showed that rTMS combined with motor training increased N100 amplitude in prefrontal,central and parietal cortices,and the motor traning only increased N100 amplitude in central cortex,significantly.In conclusion,rTMS combined with motor training might improve the limb motor function through changing the information communication between regions related with motor function,especially decreasing the informationtransmission of premotor region and increasing the parietal region.Besides,rTMS combined with motor function could also decrease the inhibited activity in prefrontal,central and parietal regions,which might be the reason of improvement of limb motor function.This study could be helpful to understand the modulation in our understanding of how rTMS-MT modulates brain activity.The methods and results in this study could be taken as reference in future studies ofthe effects of rTMS-MT in stroke patients.This paper designed a method about rTMS combined with motor traning,and studiedits effects on brain network and cortical excitability.The method was expected to be applied to the motor rehabilitation of stroke patients in the future.The results in this paper could promote the understanding of its effects on brain neural activity,furthermore,for stroke patients.