| Part 1: Research on ERP under Different Load N-back TasksObjective: This study analyzed the changes in the amplitude of event-related potentials(ERP)and observed the differences in the electrical activity of the cortex of healthy subjects under different load N-back tasks(1-back,2-back,3-back).Methods: Using the method of random entry,from September 1,2019 to January 30,2020,30 healthy college students were included,5 cases were excluded from the data,and 25 cases were finally included.Participants clean their scalp well before the formal experiment.In the confirmation practice stage,the accuracy rate of the results reached 60%,and the formal test was started.The tested N-back paradigm includes 1-back,2-back,and 3-back.For balance,the three paradigms are presented in three different orders.Participants were included in the three orders in equal proportions.Observation indicators are behavioral and EEG data.Results: 1.Differences in N-back behavior of different loads:(1)RT-hit: Single factor repeated measures analysis of variance shows that the main effect of load is significant(p=0.000).Post-hoc analysis shows that there is a difference between 1-back(average: 485.9038ms)and 2-back(average 575.2130ms)Significant difference(p<0.001).There was a significant difference between 1-back and 3-back(mean: 573.0048ms)(p<0.001),but no significant statistical difference(p>0.05)was seen between 2-back and 3-back.Therefore,in combination with the average value,it can be seen that as the load increases,the average value of RT-hit gradually increases.(2)Precision d` value: single factor repeated measurement analysis of variance shows: the main effect of load is significant(p=0.000).Post-mortem analysis shows that between 1-back(average: 3.3091)and 2-back(average 2.4404)There is a significant difference(p<0.05).There was a significant difference(p<0.001)between 1-back and 3-back(mean: 1.5331),but no significant statistical difference(p>0.05)was seen between 2-back and 3-back.Therefore,in combination with the average value,it can be seen that as the load increases,the average value of the accuracy d’value gradually decreases.2.Differences in ERP components of N-back with different loads:(1)The amplitude of component P2 is shown by repeated measurement analysis of variance: the main effect of load is not significant,the interaction effect between load and front and back position is not significant,the interaction effect between load and left and right position is not significant,and the interaction effect of load × front and rear position × left and right position is not significant(ps>0.05).(2)The amplitude of the component N2 is shown by repeated measurement analysis of variance: the main effect of load is significant(p<0.05),and the paired comparison analysis shows that there is a marginal significant effect between 1-back and 3-back(p=0.067).It shows that the amplitude of N2 is the highest under the 3-back condition and the lowest under the 1-back condition.The interaction effect between load and anterior and posterior positions was significant(p<0.05).Post-mortem analysis showed that N2 in the forehead area(F3,F4,Fz),midline position(C3,C4,Cz)and posterior parietal area(P3,P4,Pz)The components all changed significantly with the increase of task load(ps<0.05).The interaction effect of load and left-right position is not significant,and the interaction effect of load×front-rear position×left-right position is not significant(ps>0.05).(3)The amplitude of the component P3 is shown by repeated measurement analysis of variance: the main effect of load is significant(p=0.000).Further paired-sample t-test showed that pairwise comparisons between the three loads showed that there were significant differences between the loads(ps <0.05).The interaction effects of load and front and rear positions,the interaction effects of load and left and right positions,and the interaction effects of load × front and rear positions × left and right positions were not significant(ps>0.05).(4)The amplitude of the component NSW was analyzed by repeated measurement analysis of variance,and it was shown that the interaction effect between load and front and rear positions was marginally significant(p=0.055).The interaction effect between load and left and right position is significant(p<0.05).Post-hoc analysis showed that NSW in the left brain area(F3,C3,P3)increased with load(p <0.05).The main effect of load and the interaction effect of load × front and rear position × left and right position were not significant(ps>0.05).3.Correlation analysis of behavioral and EEG data: The NSW amplitude of the P3 electrode has a significant negative correlation with the d` value(p<0.001)Conclusion:Except that the amplitude of P2 did not change significantly.The amplitudes of P3,N2 and NSW all change with the increase of load.To further understand the electrophysiological mechanism of working memory load,a certain theoretical basis is provided.Part 2: The Effect of Different Frequencies of Electroacupuncture at Shenting and Baihui Points on Working Memory Performance of Healthy Adults with Different LoadsObjective: In this study,three stimulation methods,6Hz-EA(theta frequency band),40Hz-EA(gamma frequency band),and Sham-EA were selected to stimulate Shenting and Baihui points.Compare the effects of different frequencies of EA stimulation on the working memory test scores of healthy subjects.Methods: Using the method of random enrollment,30 healthy college students were enrolled from September 1,2019 to September 30,2020.According to the subject’s internal crossover design(3×2 crossover design mode),each subject receives the following 3 stimuli in different stages and in different orders: a: 6Hz-EA(theta frequency band);b: 40Hz-EA(gamma band);c: Sham-EA(no power connected).According to the order of stimulation,the subjects will be randomly divided into 3 different stimulation groups,A/B/C,at a ratio of 1:1:1.The specific stimulation sequence is as follows: A: abc,B: bca,C: cab.The N-back task was used to evaluate working memory performance before and after stimulation.There is a 7-day washout period between each stimulation.The duration of each stimulation is 30 min.Result: 1.RT-hit value: After two-factor repeated measurement analysis of variance,the results show that the interaction effect between the stimulus type and time under each load is not significant(ps>0.05).However,the statistical results based on time as the main effect,there are significant differences before and after the three load interventions(ps<0.001),suggesting that the exercise effect of the subjects is significant,but it has nothing to do with the type of stimulation.2.d` value: after two-factor repeated measurement analysis of variance,the results show that time and stimulus type under 1-back and 2-back loads,stimulus type × time have no mutual effect(ps>0.05),and the main effect of stimulus type was no statistical difference between the main effects of time and time.However,under the 3-back load,there was an interaction between the type of stimulation and the time(p=0.035).The post-hoc analysis found that there were significant differences before and after the intervention in the 6Hz-EA group(p <0.001 after adjustment).Conclusion: Compared with 40Hz-EA and fake-EA,6Hz-EA can significantly improve the accuracy of the 3-back test of healthy subjects.To further explore 6-Hz EA to stimulate Shenting and Baihui acupoints,to provide a preliminary theoretical basis for clinical research on improving working memory.Part3: Observation on the Effect of Different Frequencies of Electroacupuncture at Shenting and Baihui on ERP Components Related to Working Memory in Healthy Adults with Different LoadsObjective: In this study,three stimulation methods,6Hz-EA(theta frequency band),40Hz-EA(gamma frequency band),and sham-EA were selected to stimulate Shenting and Baihui points to compare the effects of electroacupuncture at different frequencies on ERP components related to working memory in healthy subjects.Methods: Using the method of random enrollment,30 healthy college students were enrolled from September 1,2019 to January 30,2020.5 cases were discontinued and 7 cases were eliminated.Finally,18 cases were included in the analysis.The observation indicators are P2(200-250ms),N2(250-300ms),P3(300-400ms)and NSW(500-1000ms)4 ERP components.Three loads of 1-back,2-back,and 3-back were separately performed.Under each load,a 3×2×9 repeated measurement analysis of variance was performed for each component.Among them,3 are three stimulation methods.2 is two time points,namely before stimulation and after stimulation.9 is 9 electrodes(ie: F3,Fz,F4/C3,Cz,C4/P3,Pz,P4).Result: 1.Under 1-back load: the four components(P2,N2,P3,NSW)are not significant in the stimulus type as the main effect,the stimulus type×time interaction effect,and the stimulus type×time×channel interaction effect(ps> 0.05).2.Under 2-back load:(1)The two components of P2 and N2 have a significant interaction effect in the stimulation type × time(ps<0.05).Among them,after P2 analysis,the 6H-EA intervention was weaker than before the intervention,and there was a marginal effect.After correction,p=0.088.The Sham-EA intervention was significantly stronger than before the intervention,with significant statistical significance,p=0.033<0.05.Post-hoc analysis of the N2 component,the 6H-EA intervention was significantly stronger than before the intervention,with significant statistical significance,p=0.009<0.05.After the Sham-EA intervention,it was significantly weaker than before the intervention,and there was a marginal effect.After correction,p=0.066.(2)The two components of P3 and NSW have no significant effects on the stimulation type,the stimulation type×time interaction effect,and the stimulation type×time×channel interaction effect(ps>0.05).3.Under 3-back load:(1)The interaction effect of P2 in stimulation type×time×channel is significant(p=0.020).Simple analysis after the event: the amplitude of electrodes C3,Pz,and P3 after 40 Hz intervention was significantly weaker than that before intervention(ps<0.05),and the amplitude of Fz and F4 was significantly increased after intervention of electroacupuncture(ps<0.05).The main effect of stimulus type and the interaction effect of stimulus type×time were not significant(ps>0.05).(2)N2 is marginally significant in stimulus type×time×channel interaction effect(p=0.053).Simple analysis after the event: the amplitude of electrodes Pz and P3 was significantly increased after 40 Hz intervention than before intervention(ps<0.05),and the amplitude of electrodes Fz and F4 was significantly weaker after intervention of sham-electroacupuncture than before intervention(ps<0.05).The main effect of stimulus type and the interaction effect of stimulus type×time were not significant(ps>0.05).(3)P3 is marginally significant in stimulus type×time×channel interaction effect(p=0.070).Simple analysis after the event: The amplitudes of electrodes F3 and F4 were significantly weaker after 6 Hz intervention than before intervention(ps<0.05),and Pz,P3,P4,and Cz were significantly weaker than before intervention after sham electroacupuncture(ps<0.05).The main effect of stimulus type and the interaction effect of stimulus type×time were not significant(ps>0.05).(4)NSW is marginally significant in stimulus type×time×channel interaction effect(p=0.095).Simple analysis after the event: The amplitude of electrodes F3 and Fz after 6 Hz intervention was significantly higher than that before intervention(ps<0.05).The main effect of stimulus type and the interaction effect of stimulus type×time were not significant(ps>0.05).4.The subsequent analysis of the correlation between behavioral and EEG data found that the NSW component of electrode Fz under 6Hz-EA stimulation and the N2 component of electrode F4 under sham-EA stimulation have a significant negative correlation with the d` value.Conclusion: In the high-load n-back test,40Hz-EA and 6Hz-EA adjusted the early and late components in the working memory stage of the subjects,respectively.Provide a certain theoretical basis for the study of the mechanism of electrical acupuncture stimulation on working memory.Part 4: The effect of different frequency electroacupuncture interventions at Shenting and Baihui on the working memory of post-stroke patientsObjective: In this study,6Hz-EA(theta frequency band)and 40Hz-EA(gamma frequency band)and ordinary acupuncture were selected to stimulate Shenting and Baihui points to compare the effects of different electrical stimulation frequencies on the working memory test scores of patients after stroke.Methods: Using the method of randomization,from May 1,2020 to January 30,2021,73 post-stroke patients were included.During the experiment,5 cases were eliminated,4 cases were dropped,and 64 patients were finally included in the analysis.Among them,there were 21 cases in the 40Hz-EA group,21 cases in the 6Hz-EA group,and 22 cases in the ordinary acupuncture group.The duration of the each stimulation is 30 minutes,and the stimulation is 5 times a week.The accuracy and response time of 1 patient-back paradigm assessment were collected before treatment(0 weeks)and after the end of treatment(two weeks).Result: 1.d’ value: comparison between groups: Kruskal-Wallis H test was used.Statistics found that there was no significant difference in the d` values of the three groups before and after the intervention(ps>0.05).It shows that the three stimulation methods have no significant difference in improving the accuracy of patients.2.RT-hit value: comparison between groups: Kruskal-Wallis H test was used.There was no significant difference in the RT-hit value of the three groups before stimulation(p>0.05).It suggests that the three groups are comparable.There were significant differences in the RT-hit values of the three groups after stimulation(p<0.05).The Bonferroni method was used to correct the results of the pairwise comparison afterwards.The difference between the 40Hz-electroacupuncture group and the 6Hz-EA group was statistically significant(p<0.05 after adjustment),and the difference between the 40Hz-electroacupuncture group and the ordinary acupuncture group was statistically significant(p<0.05).3.Subsequent comparison of the difference between the three groups before and after stimulation found that the RT-hit value of the 40Hz-electroacupuncture group was significantly improved than that of the 6Hz-EA(p<0.05).Conclusion: Compared with the other two programs,40Hz-EA can significantly improve the response of post-stroke patients when performing the n-back test,and it is worthy of further clinical research. |
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