| Motor inhibition refers to the coordination of the perceptual motor system to suppress dominant or discomfortable responses during changing movements,which divided into proactive inhibition and reactive inhibition.Previous studies have shown significant motor inhibition deficits in patients with Parkinson’s disease(PD).Decreased inhibitory ability is closely related to motor symptoms,and will gradually worsen with the development of the disease,and cannot be effectively relieved by clinical drug treatment,causing serious disturbance to the patient’s life.The reason why the inhibition ability of PD patients is impaired is that the degeneration of dopaminergic neurons induces the functional change of the "frontal-basal ganglia" neural circuit.Motor inhibition in different modes is driven by different neural circuits with specific temporal characteristics,but how these neural circuits regulate motor inhibition in PD patients and the impact of long-term exercise intervention on their motor inhibition has not been clearly determined.The Stop-signal task,the gold standard for evaluating stop efficiency,evaluates motor inhibition by measuring stop-signal reaction time(SSRT).Transcranial magnetic stimulation(TMS)can facilitate or inhibit neural activity by stimulating specific areas of the cerebral cortex,revealing the deep neural mechanisms of specific cognitive processes.In this study,the Stop-signal task was selected and multiple paradigms of TMS technology was adopted to explore the electrophysiological characteristics of motor inhibition in PD patients and the influence of long-term exercise intervention on their motor inhibition ability,combined with the interhemispheric interaction changes of brain networks in resting state and task state.Study 1(Experiment 1)used a modified version of the Stop-signal task to explore the performance of motor inhibition behavior in 40 PD patients and 40 age-matched Healthy control(HC)under different modes.In Study 2,the interhemispheric interaction of 22 PD patients and 22 HC groups was detected under different modes to further understand the electrophysiological mechanism of PD motor inhibition deficit.(Experiment 2)adopted the offline dual-site TMS to investigate the changes of interhemispheric interaction between the right DLPFC-left M1 and the right pre-SMA-left M1 under different interstimulus intervals(ISIs)and stimulus intensities in the resting state.Then,using the online dual-site TMS,the first stimulus was applied to the right DLPFC(experiment 3)and right pre-SMA(experiment 4)during the motor inhibition task,and the second stimulus was applied to the left M1,and the interhemispheric interaction changes of the right DLPFC-left M1 and the right pre-SMA-left M1 were investigated respectively.Based on the results of experiment 3 and experiment 4,Study 3 explored the improvement effect of longterm exercise on motor inhibition deficiency in patients of PD.60 PD patients were randomly divided into Wuqinxi exercise group and stretching exercise group for 24 weeks longitudinal exercise intervention.(Experiment 5)measured motor symptoms,gait ability,emotional state,sleep quality,cognitive ability and quality of life of PD patients before and after exercise intervention.Then used paired-pulse TMS was used to investigate the changes of short-interval intracortical inhibition(SICI)in PD patients before and after exercise intervention.(Experiment 6)used the dual-site TMS to investigate the effect of 24 weeks of exercise intervention on the changes in interaction and motor inhibition of the right DLPFC-left M1 in PD patients.The results are as follows: The results of experiment1 showed that compared with the HC group,the motor inhibition defect in PD patients was mainly manifested in the reactive inhibition,and there was no significant difference in proactive inhibition.The results of experiment 2 showed that when the CS stimulation intensity was 90%RMT,the interhemispheric interaction of the right DLPFC-left M1 in the PD group showed significant interhemispheric inhibition at 30 ms and 40 ms.The interhemispheric interaction of right DLPFC-left M1 in HC group showed significant interhemispheric inhibition at 50 ms.The results of experiment 3 showed that when the ISIs was 10 ms,compared with the HC group,the right DLPFC in the PD group showed excessive inhibition to the left M1 at 200 ms and 250 ms after the stop signal appearing.When the interstimulus intervals was 50 ms,the right DLPFC has insufficient disinhibition of the left M1 150 ms,200ms,and 250 ms after the stop signal.The results of experiment 4showed that when the ISIs was 10 ms or 50 ms,there was no significant difference between PD group and HC group in the changes in the interaction of right pre-SMAleft M1.The results of Experiment 5 showed that sleep quality,emotional state,motor symptoms,gait ability,and quality of life were improved in both groups compared with before exercise,but 24 weeks of exercise intervention did not have an effect on SICI.The results of experiment 6 showed that compared with before exercise,when the ISIs was 10 ms,the right DLPFC-left M1 interhemispheric interaction in the Wuqinxi exercise group was significantly increased on 200 ms after the appearance of stop signal,and the SSRT was significantly accelerated during the stopping process.Based on the findings above,the conclusions of this study are as follows:(1)There are obvious defects in reactive inhibition with early PD patients and no proactive inhibition deficit;(2)The abnormal inhibitory regulation of left M1 by right DLPFC may be a potential mechanism leading to reactive inhibition defects in PD patients;(3)24 weeks Wuqinxi exercise can enhance the disinhibition effect of right DLPFC-left M1,and improve the reactivity inhibition deficiency in PD patients. |
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