The Effects Of High-definition Transcranial Direct Current Stimulation On Cognition And Endurance Performance

Objective:Endurance exercises require athletes to maintain high-level sports ability over long periods of time,in which cognition plays an important role,especially inhibitory control and attention.Transcranial Direct Current Stimulation（t DCS）is a non-invasive brain stimulation technique that is effective in modulating cognition,but most studies just focus on the acute effects of single t DCS stimulation,and the cumulative effects of repeated t DCS interventions on cognition and endurance performance have not yet to be verified.In this study,high-definition t DCS（HD-t DCS）was used to stimulate the Left Dorsolateral Prefrontal Cortex（LDLPFC）,a key brain region of regulating cognition,for five consecutive days.The acute and cumulative effects of the intervention on cognition and endurance performance were investigated.Methods:This study was a randomized,crossover,double-blind,controlled trial with non-sports major college students at the Shanghai University of Sport（n=22;24±2years）,all subjects received either the HD-t DCS or Sham stimulation protocol randomly,and receive the other stimulation（5 consecutive sessions）followed by an adequate washout period（>30 days）.The HD-t DCS stimulation protocol used LDLPFC as the target region,using 5 electrodes（AF3,FC1,FPz,T7,Cz）,with a total stimulation electrode intensity of 1622μA（<817μA input current per electrode）for20 min,once a day for 5 days;the Sham stimulation protocol had the same electrode position as the HD-t DCS protocol,but receice stimulation only at the beginning and before the end of stimulation for 30s.Cognition assessment（before and after the intervention on day 1 and day5）,endurance performance test（post-intervention on day1 and day5）were performed.Cognition was assessed before and after the endurance test,including the Stroop task（Accuracy,Reaction Time,and Accuracy/Reaction Time）and the Attentional Network Test（ANT;including indicators of Alerting Effect,Orienting Effect,and Executive Effect）.Endurance performance was evaluated by time to exhaustion（TTE）and rate of perceived exertion（RPE）.Results:No significant adverse effects were observed during the intervention.Compared to sham stimulation,there was no significant effect of HD-t DCS on cognition and endurance performance compared to sham stimulation,including acute effects（day1）and cumulative effects（after 5 consecutive days）;but HD-t DCS significantly improved the cognition after endurance exercise,including the acute effects for alerting effect（F=4.820,p=0.034）,cumulative effects for Stroop test（inconsistent condition,F=4.174,p=0.047）and accuracy/reaction time（consistent condition,F=5.636,p=0.022）.Within-group analyses revealed significantly elevated performance on both the Stroop test and ANT test（executive effect）after HD-t DCS and sham stimulation;RPE was significantly lower after the HD-t DCS intervention in endurance performance(F_1min=3.349,p_1min=0.045;F_4min=4.282,p_4min=0.020),and post hoc tests revealed significant differences between Baseline and tests after 5consecutive HD-t DCS stimulations,while no significant changes were found in endurance exercise tests after the Sham intervention.Conclusion:Although this study did not show significant effects of HD-TDCS on pre-exercise cognition and TTE,we found that HD-t DCS could effectively improve cognition after exhaustive exercise and relieve self-fatigue.In the future,personalized stimulation can be investigated,the neuroimaging and other techniques can be used to explore the underlying mechanism of its regulation for cognition and endurance exercise,providing an auxiliary means based on neural priming for sports training and competitive sports.