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Hafezi S, Doustan M, Saemi E. The Effect of Brain Anodal and Cathodal Transcranial Direct Current Stimulation on Psychological Refractory Period at Different Stimulus-Onset Asynchrony in Non-Fatigue and Mental Fatigue Conditions. Brain Sci 2024; 14:477. [PMID: 38790455 PMCID: PMC11118837 DOI: 10.3390/brainsci14050477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/04/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
The psychological refractory period (PRP) effect occurs when two stimuli that require separate responses are presented sequentially, particularly with a short and variable time interval between them. Fatigue is a suboptimal psycho-physiological state that leads to changes in strategies. In recent years, numerous studies have investigated the effects of transcranial direct current stimulation (tDCS) on motor control. The present study aimed to investigate the effects of two tDCS methods, anodal and cathodal, on PRP in ten different conditions of stimulus-onset asynchronies (SOAs) under non-fatigue and mental fatigue conditions. The participants involved 39 male university students aged 19 to 25 years. In the pre-test, they were assessed using the PRP measurement tool under both non-fatigue and mental fatigue conditions. The mental fatigue was induced by a 30-min Stroop task. The test consisted of two stimuli with different SOAs (50, 75, 100, 150, 300, 400, 600, 900, 1200, and 1500 ms). The first was a visual stimulus with three choices (letters A, B, and C). After a random SOA, the second stimulus, a visual stimulus with three choices (colors red, yellow, and blue), was presented. Subsequently, participants were randomly assigned to the anodal, cathodal, and sham stimulation groups and underwent four consecutive sessions of tDCS stimulation. In the anodal and cathodal stimulation groups, 20 min of tDCS stimulation were applied to the PLPFC area in each session, while in the sham group, the stimulation was artificially applied. All participants were assessed using the same measurement tools as in the pre-test phase, in a post-test phase one day after the last stimulation session, and in a follow-up phase four days after that. Inferential statistics include mixed ANOVA, one-way ANOVA, independent, and dependent t-tests. The findings indicated that the response time to the second stimulus was longer at lower SOAs. However, there was no significant difference between the groups in this regard. Additionally, there was no significant difference in response time to the second stimulus between the fatigue and non-fatigue conditions, or between the groups. Therefore, tDCS had no significant effect. There was a significant difference between mental fatigue and non-fatigue conditions in the psychological refractory period. Moreover, at lower SOAs, the PRP was longer than at higher SOAs. In conditions of fatigue, the active stimulation groups (anodal and cathodal) performed better than the sham stimulation group at higher SOAs. Considering the difference in response to both stimuli at different SOAs, some central aspects of the response can be simultaneously parallel. Fatigue also affects parallel processing. This study supports the response integration phenomenon in PRP, which predicts that there will be an increase in response time to the first stimulus as the interval between the presentation of the two stimuli increases. This finding contradicts the bottleneck model. In this study, the effectiveness of cathodal and anodal tDCS on response time to the second stimulus and PRP was found to be very small.
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Affiliation(s)
| | - Mohammadreza Doustan
- Department of Motor Behavior and Sport Psychology, Faculty of Sport Sciences, Shahid Chamran University of Ahvaz, Ahvaz 6135783151, Iran; (S.H.); (E.S.)
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Cheng XR, Zhang YB, Sun DJ, Peng XY, Bao YC, Zhang F, Wang MX. Long-term repetitive transcranial direct current stimulation in patients with disorders of consciousness: a preliminary study. Brain Inj 2024; 38:68-75. [PMID: 38329075 DOI: 10.1080/02699052.2024.2304872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 01/09/2024] [Indexed: 02/09/2024]
Abstract
OBJECTIVES To investigate the effects of long-term repetitive transcranial direct current stimulation on patients with DOC in the subacute phase. METHODS In a randomized, double-blind, controlled study, 33 patients were randomly assigned to the active or sham group, and 28 patients completed the study. Patients in the active group received anodal stimulation over the DLPFC, while patients in the sham group received placebo stimulation (20 min/day, 5 days/week, for 4 weeks). The level of consciousness among patients was assessed with the Coma Recovery Scale-Revised (CRS-R) at baseline and at the end of every week from the first to the fourth week. RESULTS The CRS-R scores of both the active and sham groups showed a consistent increasing trend over time; however, the treatment effect of the active group was better than that of the sham group. In addition, there was a statistically significant difference in the total CRS-R score between the two groups at weeks 1, 2, 3 and 4. Moreover, 10 patients (71.4%) in the active group and 3 patients (21.4%) in the sham group were regarded as responders. CONCLUSION Long-term tDCS could improve the level of consciousness of patients with DOC in the subacute stage.
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Affiliation(s)
- Xiao Rong Cheng
- Department of Rehabilitation, The Second Hospital of Lanzhou University, Lan Zhou, Gan Su Province, China
| | - Yi Bao Zhang
- Department of Rehabilitation, The Second Hospital of Lanzhou University, Lan Zhou, Gan Su Province, China
| | - Deng Juan Sun
- Department of Rehabilitation, The Second Hospital of Lanzhou University, Lan Zhou, Gan Su Province, China
| | - Xiao Yun Peng
- Department of Rehabilitation, The Second Hospital of Lanzhou University, Lan Zhou, Gan Su Province, China
| | - Ying Cun Bao
- Department of Rehabilitation, The Second Hospital of Lanzhou University, Lan Zhou, Gan Su Province, China
| | - Fang Zhang
- Department of Rehabilitation, The Second Hospital of Lanzhou University, Lan Zhou, Gan Su Province, China
| | - Man Xia Wang
- Department of Neurology, The Second Hospital of Lanzhou University, Lan Zhou, Gan Su Province, China
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Teymoori H, Amiri E, Tahmasebi W, Hoseini R, Grospretre S, Machado DGDS. Effect of tDCS targeting the M1 or left DLPFC on physical performance, psychophysiological responses, and cognitive function in repeated all-out cycling: a randomized controlled trial. J Neuroeng Rehabil 2023; 20:97. [PMID: 37496055 PMCID: PMC10373277 DOI: 10.1186/s12984-023-01221-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND Despite reporting the positive effects of transcranial direct current stimulation (tDCS) on endurance performance, very few studies have investigated its efficacy in anaerobic short all-out activities. Moreover, there is still no consensus on which brain areas could provide the most favorable effects on different performance modalities. Accordingly, this study aimed to investigate the effects of anodal tDCS (a-tDCS) targeting the primary motor cortex (M1) or left dorsolateral prefrontal cortex (DLPFC) on physical performance, psychophysiological responses, and cognitive function in repeated all-out cycling. METHODS In this randomized, crossover, and double-blind study, 15 healthy physically active men underwent a-tDCS targeting M1 or the left DLPFC or sham tDCS in separate days before performing three bouts of all-out 30s cycling anaerobic test. a-tDCS was applied using 2 mA for 20 min. Peak power, mean power, fatigue index, and EMG of the quadriceps muscles were measured during each bout. Heart rate, perceived exertion, affective valence, and arousal were recorded two minutes after each bout. Color-word Stroop test and choice reaction time were measured at baseline and after the whole anaerobic test. RESULTS Neither tDCS montage significantly changed peak power, mean power, fatigue index, heart rate, affective valence, arousal, and choice reaction time (p> 0.05). a-tDCS over DLPFC significantly lowered RPE of the first bout (compared to sham; p=0.048, Δ=-12.5%) and third bout compared to the M1 (p=0.047, Δ=-12.38%) and sham (p=0.003, Δ=-10.5%), increased EMG of the Vastus Lateralis muscle during the second (p=0.016, Δ= +40.3%) and third bout (p=0.016, Δ= +42.1%) compared to sham, and improved the score of color-word Stroop test after the repeated all-out task (p=0.04, Δ= +147%). The qualitative affective response (valence and arousal) was also higher under the M1 and DLPFC compared to the sham. CONCLUSION We concluded that tDCS targeting M1 or DLPFC does not improve repeated anaerobic performance. However, the positive effect of DLPFC montage on RPE, EMG, qualitative affective responses, and cognitive function is promising and paves the path for future research using different tDCS montages to see any possible effects on anaerobic performance. TRIAL REGISTRATION This study was approved by the Ethics Committee of Razi University (IR.RAZI.REC.1400.023) and registered in the Iranian Registry of Clinical Trials (IRCT id: IRCT20210617051606N5; Registration Date: 04/02/2022).
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Affiliation(s)
- Hafez Teymoori
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Ehsan Amiri
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran.
| | - Worya Tahmasebi
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Rastegar Hoseini
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Sidney Grospretre
- EA4660-C3S Laboratory - Culture, Sports, Health and Society, University Bourgogne France- Comte, Besancon, France
| | - Daniel Gomes da Silva Machado
- Research Group in Neuroscience of the Human Movement (NeuroMove), Department of Physical Education, Federal University of Rio Grande do Norte, Natal, RN, Brazil
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Etemadi M, Amiri E, Tadibi V, Grospretre S, Valipour Dehnou V, Machado DGDS. Anodal tDCS over the left DLPFC but not M1 increases muscle activity and improves psychophysiological responses, cognitive function, and endurance performance in normobaric hypoxia: a randomized controlled trial. BMC Neurosci 2023; 24:25. [PMID: 37020275 PMCID: PMC10077713 DOI: 10.1186/s12868-023-00794-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/28/2023] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) has been shown to have positive effects on exercise performance and cognitive function in the normal ambient condition. Hypoxia is deemed a stressful situation with detrimental effects on physiological, psychological, cognitive, and perceptual responses of the body. Nevertheless, no study has evaluated the efficacy of tDCS for counteracting the negative effects of hypoxic conditions on exercise performance and cognition so far. Hence, in the present study, we investigated the effects of anodal tDCS on endurance performance, cognitive function, and perceptual responses in hypoxia. PARTICIPANTS AND METHODS Fourteen endurance-trained males participated in five experimental sessions. After familiarization and measuring peak power output in hypoxia, in the first and second sessions, through the 3rd to 5th sessions, participants performed a cycling endurance task until exhaustion after 30 min hypoxic exposure at resting position followed by 20 min of anodal stimulation of the motor cortex (M1), left dorsolateral prefrontal cortex (DLPFC), or sham-tDCS. Color-word Stroop test and choice reaction time were measured at baseline and after exhaustion. Time to exhaustion, heart rate, saturated O2, EMG amplitude of the vastus lateralis, vastus medialis, and rectus femoris muscles, RPE, affective response, and felt arousal were also measured during the task under hypoxia. RESULTS The results showed a longer time to exhaustion (+ 30.96%, p=0.036), lower RPE (- 10.23%, p = 0.045) and higher EMG amplitude of the vastus medialis muscle (+ 37.24%, p=0.003), affective response (+ 260%, p=0.035) and felt arousal (+ 28.9%, p=0.029) in the DLPFC tDCS compared to sham. The choice reaction time was shorter in DLPFC tDCS compared to sham (- 17.55%, p=0.029), and no differences were seen in the color-word Stroop test among the conditions under hypoxia. M1 tDCS resulted in no significant effect for any outcome measure. CONCLUSIONS We concluded that, as a novel finding, anodal stimulation of the left DLPFC might provide an ergogenic aid for endurance performance and cognitive function under the hypoxic condition probably via increasing neural drive to the working muscles, lowering RPE, and increasing perceptual responses.
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Affiliation(s)
- Matin Etemadi
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Ehsan Amiri
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran.
- Room. 73, Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, University Avenue, Taq-E Bostan, Kermanshah, 674441497, Iran.
| | - Vahid Tadibi
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Sidney Grospretre
- EA4660-C3S Laboratory-Culture, Sports, Health and Society, University Bourgogne France-Comte, Besancon, France
| | - Vahid Valipour Dehnou
- Department of Sports Sciences, Faculty of Literature and Human Sciences, Lorestan University, Khorramabad, Iran
| | - Daniel Gomes da Silva Machado
- Research Group in Neuroscience of Human Movement (NeuroMove), Department of Physical Education, Federal University of Rio Grande Do Norte, Natal, RN, Brazil
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