Research On Neural Mechanism Based On Rhythmic Movement

Under the control of the nervous system,human beings can coordinate various finger joints to fulfill various complex and delicate actions.Finger-related motion accounts for 54% of the entire human activity and 90% of the upper limb movement.Therefore,it is of great significance to study the relevant neural regulation mechanisms and motion pattern of finger movement,which not only help to establish a theoretical model for evaluating motor function and provide a clinical diagnosis basis,but also have practical value in the application of rehabilitation medicine research,manipulator control,and prosthetic research.This article explored the behavior and brain regulation mechanisms in both fast and slow modes by designing repeated finger tapping movements following auditory-cued in different frequencies at 0.5,1,2,3,and 4 Hz.The specific research work are as follows:(1)By measuring somatosensory evoked potentials(SSEP)and somatosensory temporal discrimination threshold(STDT),the contribution of sensory gating in the subcortical level and primary somatosensory cortex(S1)was investigated.The results showed that when performing finger movements with fast tapping rate(3 and 4 Hz),sensory gating existed in the subcortical and S1;When performing finger movements with slow tapping rate(0.5 and 1 Hz),sensory gating only existed in S1.Compared with slow movements,sensory gating in S1 and STDT is greater during fast movements.(2)By recording EMG during movement,following with calculating strength,task complexity and mean phase shift,the behavior mechanism during finger tapping movements in different frequencies was investigated.We found that there are no significant differences in strength and task complexity during five different tapping rates;the external cue and action were synchronized during slow movement,while the external cue and action were not synchronized during fast movement.There was a significant lag between them.In addition,STDT was negatively correlated with mean phase shift.This showed that the inhibition of sensory gating in S1 can promote the performance of finger tapping movements by enhancing its ability to analyze temporal information.(3)By measuring the F-wave,the spinal cord excitability in different frequencies was studied.The experimental results showed that compared with slow movements,the amplitude and persistence of F-waves was greater during fast movements.Therefore,the present study concluded:(1)During fast movements,the input sensory information was processed in the subcortical and S1 level,while during slow movements,it was only processed in the S1 level;(2)In the slow movement,the subject executed the movements according to auditory cue;while in fast movement,the subjects did not have time to execute the movements after they hear the indication sound.Instead,they spontaneously followed the rhythm of auditory-cued to do finger tapping movement;(3)Compared with slow movement,spinal cord activation was greater during fast movement.