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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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Zhang F, Han Y, Wang H, Li Y, Tang D. Effects of transcranial direct current stimulation on motor learning in healthy elderly individuals: a systematic review and meta-analysis. Somatosens Mot Res 2024:1-11. [PMID: 38319133 DOI: 10.1080/08990220.2024.2310851] [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: 07/19/2022] [Accepted: 01/02/2024] [Indexed: 02/07/2024]
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is widely used in motor recovery. Nevertheless, whether tDCS improves motor learning in healthy older adults is still controversial. This review aims to investigate the effectiveness of tDCS on motor learning in healthy elderly individuals. METHODS The PubMed, Cochrane Library, Web of Science and Embase databases were initially searched from inception to December 5, 2022. The standard mean difference (SMD) with the corresponding 95% confidence intervals (CIs) were analysed via random-effect models. RESULTS Compared with the sham group, no significant effects were found regarding improvement in motor learning based on the speed or accuracy of the task and reaction time for the tDCS intervention group. After subgroup analysis, a significant effect was found for improved motor learning based on reaction time in the primary motor cortex (M1)-cerebellar group. CONCLUSIONS This review revealed that tDCS had no significant effect on improving the speed or accuracy of motor learning in healthy elderly adults. However, it has a significant effect on improving the motor learning ability based on the reaction time of the task (mainly referring to the tDCS stimulation position of M1 and cerebellar), although the results have obvious heterogeneity and uncertainty.
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Affiliation(s)
- Fusheng Zhang
- College of Physical Education and Health, Guangxi Normal University, Guilin, China
- School of Physical Education, Zhaotong University, Zhaotong, China
| | - Yanbai Han
- College of Physical Education and Health, Guangxi Normal University, Guilin, China
| | - Hongli Wang
- College of Physical Education and Health, Guangxi Normal University, Guilin, China
| | - Yong Li
- College of Physical Education and Health, Guangxi Normal University, Guilin, China
| | - Dingyu Tang
- School of Physical Education, Zhaotong University, Zhaotong, China
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Shiba T, Mizuta N, Hasui N, Kominami Y, Nakatani T, Taguchi J, Morioka S. Effect of bihemispheric transcranial direct current stimulation on distal upper limb function and corticospinal tract excitability in a patient with subacute stroke: a case study. FRONTIERS IN REHABILITATION SCIENCES 2023; 4:1250579. [PMID: 37732289 PMCID: PMC10507690 DOI: 10.3389/fresc.2023.1250579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/21/2023] [Indexed: 09/22/2023]
Abstract
Introduction Activation of the unaffected hemisphere contributes to motor function recovery post stroke in patients with severe upper limb motor paralysis. Transcranial direct current stimulation (tDCS) has been used in stroke rehabilitation to increase the excitability of motor-related areas. tDCS has been reported to improve upper limb motor function; nonetheless, its effects on corticospinal tract excitability and muscle activity patterns during upper limb exercise remain unclear. Additionally, it is unclear whether simultaneously applied bihemispheric tDCS is more effective than anodal tDCS, which stimulates only one hemisphere. This study examined the effects of bihemispheric tDCS training on corticospinal tract excitability and muscle activity patterns during upper limb movements in a patient with subacute stroke. Methods In this single-case retrospective study, the Fugl-Meyer Assessment, Box and Block Test, electromyography, and intermuscular coherence measurement were performed. Intermuscular coherence was calculated at 15-30 Hz, which reflects corticospinal tract excitability. Results The results indicated that bihemispheric tDCS improved the Fugl-Meyer Assessment, Box and Block Test, co-contraction, and intermuscular coherence results, as compared with anodal tDCS. Discussion: These results reveal that upper limb training with bihemispheric tDCS improves corticospinal tract excitability and muscle activity patterns in patients with subacute stroke.
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Affiliation(s)
- Takahiro Shiba
- Department of Therapy, Takarazuka Rehabilitation Hospital, Medical Corporation SHOWAKAI, Hyogo, Japan
| | - Naomichi Mizuta
- Department of Rehabilitation, Faculty of Health Sciences, Nihon Fukushi University, Aichi, Japan
- Neurorehabilitation Research Center, Kio University, Nara, Japan
| | - Naruhito Hasui
- Department of Therapy, Takarazuka Rehabilitation Hospital, Medical Corporation SHOWAKAI, Hyogo, Japan
- Department of Neurorehabilitation, Graduate School of Health Sciences, Kio University, Nara, Japan
| | - Yohei Kominami
- Department of Therapy, Takarazuka Rehabilitation Hospital, Medical Corporation SHOWAKAI, Hyogo, Japan
| | - Tomoki Nakatani
- Department of Therapy, Takarazuka Rehabilitation Hospital, Medical Corporation SHOWAKAI, Hyogo, Japan
| | - Junji Taguchi
- Department of Therapy, Takarazuka Rehabilitation Hospital, Medical Corporation SHOWAKAI, Hyogo, Japan
| | - Shu Morioka
- Neurorehabilitation Research Center, Kio University, Nara, Japan
- Department of Neurorehabilitation, Graduate School of Health Sciences, Kio University, Nara, Japan
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Kim H, Hur JK, Kwon M, Kim S, Zoh Y, Ahn WY. Causal role of the dorsolateral prefrontal cortex in modulating the balance between Pavlovian and instrumental systems in the punishment domain. PLoS One 2023; 18:e0286632. [PMID: 37267307 PMCID: PMC10237433 DOI: 10.1371/journal.pone.0286632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 05/19/2023] [Indexed: 06/04/2023] Open
Abstract
Previous literature suggests that a balance between Pavlovian and instrumental decision-making systems is critical for optimal decision-making. Pavlovian bias (i.e., approach toward reward-predictive stimuli and avoid punishment-predictive stimuli) often contrasts with the instrumental response. Although recent neuroimaging studies have identified brain regions that may be related to Pavlovian bias, including the dorsolateral prefrontal cortex (dlPFC), it is unclear whether a causal relationship exists. Therefore, we investigated whether upregulation of the dlPFC using transcranial current direct stimulation (tDCS) would reduce Pavlovian bias. In this double-blind study, participants were assigned to the anodal or the sham group; they received stimulation over the right dlPFC for 3 successive days. On the last day, participants performed a reinforcement learning task known as the orthogonalized go/no-go task; this was used to assess each participant's degree of Pavlovian bias in reward and punishment domains. We used computational modeling and hierarchical Bayesian analysis to estimate model parameters reflecting latent cognitive processes, including Pavlovian bias, go bias, and choice randomness. Several computational models were compared; the model with separate Pavlovian bias parameters for reward and punishment domains demonstrated the best model fit. When using a behavioral index of Pavlovian bias, the anodal group showed significantly lower Pavlovian bias in the punishment domain, but not in the reward domain, compared with the sham group. In addition, computational modeling showed that Pavlovian bias parameter in the punishment domain was lower in the anodal group than in the sham group, which is consistent with the behavioral findings. The anodal group also showed a lower go bias and choice randomness, compared with the sham group. These findings suggest that anodal tDCS may lead to behavioral suppression or change in Pavlovian bias in the punishment domain, which will help to improve comprehension of the causal neural mechanism.
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Affiliation(s)
- Hyeonjin Kim
- Department of Psychology, Seoul National University, Seoul, Korea
| | - Jihyun K. Hur
- Department of Psychology, Yale University, New Haven, Connecticut, United States of America
| | - Mina Kwon
- Department of Psychology, Seoul National University, Seoul, Korea
| | - Soyeon Kim
- Department of Psychology, Seoul National University, Seoul, Korea
| | - Yoonseo Zoh
- Department of Psychology, Princeton University, Princeton, New Jersey, United States of America
| | - Woo-Young Ahn
- Department of Psychology, Seoul National University, Seoul, Korea
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
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Kim H, Lee G, Lee J, Kim YH. Alterations in learning-related cortical activation and functional connectivity by high-definition transcranial direct current stimulation after stroke: an fNIRS study. Front Neurosci 2023; 17:1189420. [PMID: 37332855 PMCID: PMC10275383 DOI: 10.3389/fnins.2023.1189420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 05/04/2023] [Indexed: 06/20/2023] Open
Abstract
Introduction Motor learning is a key component of stroke neurorehabilitation. High-definition transcranial direct current stimulation (HD-tDCS) was recently developed as a tDCS technique that increases the accuracy of current delivery to the brain using arrays of small electrodes. The purpose of this study was to investigate whether HD-tDCS alters learning-related cortical activation and functional connectivity in stroke patients using functional near-infrared spectroscopy (fNIRS). Methods Using a sham-controlled crossover study design, 16 chronic stroke patients were randomly assigned to one of two intervention conditions. Both groups performed the sequential finger tapping task (SFTT) on five consecutive days, either with (a) real HD-tDCS or (b) with sham HD-tDCS. HD-tDCS (1 mA for 20 min, 4 × 1) was administered to C3 or C4 (according to lesion side). fNIRS signals were measured during the SFTT with the affected hand before (baseline) and after each intervention using fNIRS measurement system. Cortical activation and functional connectivity of NIRS signals were analyzed using a statistical parametric mapping open-source software package (NIRS-SPM), OptoNet II®. Results In the real HD-tDCS condition, oxyHb concentration increased significantly in the ipsilesional primary motor cortex (M1). Connectivity between the ipsilesional M1 and the premotor cortex (PM) was noticeably strengthened after real HD-tDCS compared with baseline. Motor performance also significantly improved, as shown in response time during the SFTT. In the sham HD-tDCS condition, functional connectivity between contralesional M1 and sensory cortex was enhanced compared with baseline. There was tendency toward improvement in SFTT response time, but without significance. Discussion The results of this study indicated that HD-tDCS could modulate learning-related cortical activity and functional connectivity within motor networks to enhance motor learning performance. HD-tDCS can be used as an additional tool for enhancing motor learning during hand rehabilitation for chronic stroke patients.
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Affiliation(s)
- Heegoo Kim
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Seoul, Republic of Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Technology (SAIHST), Sungkyunkwan University, Seoul, Republic of Korea
- Department of Rehabilitation Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
| | - Gihyoun Lee
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Seoul, Republic of Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Technology (SAIHST), Sungkyunkwan University, Seoul, Republic of Korea
- Department of Physical and Rehabilitation Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Jungsoo Lee
- Department of Rehabilitation Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
| | - Yun-Hee Kim
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Seoul, Republic of Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Technology (SAIHST), Sungkyunkwan University, Seoul, Republic of Korea
- Department of Physical and Rehabilitation Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
- Haeundae Sharing and Happiness Hospital, Pusan, Republic of Korea
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Nejati V, Mirikaram F, Rad JA. Transcranial direct current stimulation alters the process of reward processing in children with ADHD: Evidence from cognitive modeling. Neurophysiol Clin 2023; 53:102884. [PMID: 37224617 DOI: 10.1016/j.neucli.2023.102884] [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: 11/25/2022] [Revised: 04/21/2023] [Accepted: 04/21/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND The ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) are the neural underpinnings of reward processing, which is impaired in individuals with attention deficit hyperactivity disorder (ADHD). In the present study, we aimed to explore the impact of the vmPFC and the dlPFC regulation on reward processing. METHODS Twenty-six children with ADHD performed the balloon analogue risk-taking task (BART) and chocolate delay discounting task (CDDT) during five different sessions of transcranial direct current stimulation (tDCS), separated by a one-week interval: anodal left dlPFC/cathodal right vmPFC, the reversed electrode positioning, anodal left dlPFC stimulation with extracranial return electrode, anodal right vmPFC stimulation with extracranial return electrodes, and sham stimulation. Four-parameter and constant-sensitivity models were used to model the data. RESULTS In the BART, anodal dlPFC/cathodal vmPFC stimulation facilitated conservative decision making, anodal tDCS over dlPFC with extracranial return electrode increased positive beliefs about the explosion of a balloon, and anodal vmPFC/cathodal dlPFC stimulation reduced ongoing learning in the process of decision making. In the CDDT, anodal vmPFC stimulation with extracranial return electrode decreased impatience in the process of the task. CONCLUSION These results suggest a role of the left dlPFC and right vmPFC in the outcome of decision making and the process of risky decision making and delay discounting.
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Affiliation(s)
- Vahid Nejati
- Department of Psychology, Shahid Beheshti University, Tehran, Iran.
| | - Fateme Mirikaram
- Department of Psychology, Shahid Beheshti University, Tehran, Iran
| | - Jamal Amani Rad
- Department of Cognitive Modeling, Institute of Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran
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Xiong HY, Cao YQ, Du SH, Yang QH, He SY, Wang XQ. Effects of High-Definition Transcranial Direct Current Stimulation Targeting the Anterior Cingulate Cortex on the Pain Thresholds: A Randomized Controlled Trial. PAIN MEDICINE 2023; 24:89-98. [PMID: 36066447 DOI: 10.1093/pm/pnac135] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/24/2022] [Accepted: 07/30/2022] [Indexed: 02/06/2023]
Abstract
BACKGROUND The majority of existing clinical studies used active transcranial direct current stimulation (tDCS) over superficial areas of the pain neuromatrix to regulate pain, with conflicting results. Few studies have investigated the effect of tDCS on pain thresholds by focusing on targets in deep parts of the pain neuromatrix. METHODS This study applied a single session of high-definition tDCS (HD-tDCS) targeting the anterior cingulate cortex (ACC) and used a parallel and sham-controlled design to compare the antinociceptive effects in healthy individuals by assessing changes in pain thresholds. Sixty-six female individuals (mean age, 20.5 ± 2.4 years) were randomly allocated into the anodal, cathodal, or sham HD-tDCS groups. The primary outcome of the study was pain thresholds (pressure pain threshold, heat pain threshold, and cold pain threshold), which were evaluated before and after stimulation through the use of quantitative sensory tests. RESULTS Only cathodal HD-tDCS targeting the ACC significantly increased heat pain threshold (P < 0.05) and pressure pain threshold (P < 0.01) in healthy individuals compared with sham stimulation. Neither anodal nor cathodal HD-tDCS showed significant analgesic effects on cold pain threshold. Furthermore, no statistically significant difference was found in pain thresholds between anodal and sham HD-tDCS (P > 0.38). Independent of HD-tDCS protocols, the positive and negative affective schedule scores were decreased immediately after stimulation compared with baseline. CONCLUSIONS The present study has found that cathodal HD-tDCS targeting the ACC provided a strong antinociceptive effect (increase in pain threshold), demonstrating a positive biological effect of HD-tDCS.
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Affiliation(s)
- Huan-Yu Xiong
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Yin-Quan Cao
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Shu-Hao Du
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Qi-Hao Yang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Si-Yi He
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Xue-Qiang Wang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China.,Department of Rehabilitation Medicine, Shanghai Shangti Orthopaedic Hospital, Shanghai, China
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Müller D, Habel U, Brodkin ES, Weidler C. High-definition transcranial direct current stimulation (HD-tDCS) for the enhancement of working memory - A systematic review and meta-analysis of healthy adults. Brain Stimul 2022; 15:1475-1485. [PMID: 36371009 DOI: 10.1016/j.brs.2022.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 10/19/2022] [Accepted: 11/04/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND High-definition transcranial direct current stimulation (HD-tDCS) administers weak electric current through multiple electrodes, enabling focal brain stimulation. An increasing number of studies investigate the effects of anodal HD-tDCS on the enhancement of working memory (WM). The effectiveness of the technique is, however, still unclear. OBJECTIVE/HYPOTHESIS This systematic review analyzed the current literature on anodal HD-tDCS for WM enhancement, investigating its effectiveness and the influence of different moderators to allow for comparison with conventional tDCS. METHODS Following the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines, a comprehensive literature review was conducted using PubMed, Web of Science, and Scopus. Sixteen single- or double-blind, sham-controlled studies were included in the review. Eleven studies were included in the meta-analysis, focusing solely on stimulation of the left prefrontal cortex (PFC). RESULTS No significant effect of anodal HD-tDCS on the left PFC for WM accuracy (g = 0.23, p = 0.08), and reaction time (g = 0.03, p = 0.75 after trim-and-fill) was found. Further analysis revealed heterogeneity in the accuracy results. Here, moderator analysis indicated a significant difference between studies that repeatedly used HD-tDCS enhanced WM training and studies with one-time use of HD-tDCS (p < 0.001), the latter having a smaller effect size. Another moderator was the research design, with differences between within-subjects-, and between-subjects designs (p < 0.05). Within-subject studies showed lower effect sizes and substantially lower heterogeneity. Qualitative analysis reinforced this finding and indicated that the motivation of the participant to engage in the task also moderates the effectiveness of HD-tDCS. CONCLUSION This review highlights the importance of inter-individual differences and the setup for the effectiveness of anodal, HD-tDCS augmented WM training. Limited evidence for increased sensitivity of HD-tDCS to these factors as compared to conventional tDCS is provided.
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Affiliation(s)
- Dario Müller
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, Pauwelsstraße 30, Aachen, 52074, North Rhine-Westphalia, Germany.
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, Pauwelsstraße 30, Aachen, 52074, North Rhine-Westphalia, Germany; Institute of Neuroscience and Medicine, JARA-Institute Brain Structure Function Relationship (INM 10), Research Center Jülich, Wilhelm-Johnen-Straße, 52438, Jülich, Germany
| | - Edward S Brodkin
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, 3535 Market Street, Suite 3080, Philadelphia, PA, 19104-3309, USA
| | - Carmen Weidler
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, Pauwelsstraße 30, Aachen, 52074, North Rhine-Westphalia, Germany
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Siew-Pin Leuk J, Yow KE, Zi-Xin Tan C, Hendy AM, Kar-Wing Tan M, Hock-Beng Ng T, Teo WP. A meta-analytical review of transcranial direct current stimulation parameters on upper limb motor learning in healthy older adults and people with Parkinson's disease. Rev Neurosci 2022; 34:325-348. [PMID: 36138560 DOI: 10.1515/revneuro-2022-0073] [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: 06/14/2022] [Accepted: 08/22/2022] [Indexed: 11/15/2022]
Abstract
Current literature lacks consolidated evidence for the impact of stimulation parameters on the effects of transcranial direct current stimulation (tDCS) in enhancing upper limb motor learning. Hence, we aim to synthesise available methodologies and results to guide future research on the usage of tDCS on upper limb motor learning, specifically in older adults and Parkinson's disease (PD). Thirty-two studies (Healthy older adults, N = 526, M = 67.25, SD = 4.30 years; PD, N = 216, M = 66.62, SD = 6.25 years) were included in the meta-analysis. All included studies consisted of active and sham protocols. Random effect meta-analyses were conducted for (i) subjects (healthy older adults and PD); (ii) intensity (1.0, 1.5, 2 mA); (iii) electrode montage (unilateral anodal, bilateral anodal, unilateral cathodal); (iv) stimulation site (cerebellum, frontal, motor, premotor, SMA, somatosensory); (v) protocol (online, offline). Significant tDCS effect on motor learning was reported for both populations, intensity 1.0 and 2.0 mA, unilateral anodal and cathodal stimulation, stimulation site of the motor and premotor cortex, and both online and offline protocols. Regression showed no significant relationship between tDCS effects and density. The efficacy of tDCS is also not affected by the number of sessions. However, studies that reported only single session tDCS found significant negative association between duration with motor learning outcomes. Our findings suggest that different stimulation parameters enhanced upper limb motor learning in older adults and PD. Future research should combine tDCS with neuroimaging techniques to help with optimisation of the stimulation parameters, considering the type of task and population.
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Affiliation(s)
- Jessie Siew-Pin Leuk
- Physical Education and Sports Science (PESS) Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore
| | - Kai-En Yow
- Physical Education and Sports Science (PESS) Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore
| | - Clenyce Zi-Xin Tan
- Physical Education and Sports Science (PESS) Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore
| | - Ashlee M Hendy
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences (SENS), Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
| | - Mika Kar-Wing Tan
- Physical Education and Sports Science (PESS) Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore
| | - Tommy Hock-Beng Ng
- Physical Education and Sports Science (PESS) Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore
| | - Wei-Peng Teo
- Physical Education and Sports Science (PESS) Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore
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Dalong G, Yufei Q, Lei Y, Pengfei L, Anqi Y, Zichuan G, Cong W, Yubin Z. Modulation of thalamic network connectivity using transcranial direct current stimulation based on resting-state functional magnetic resonance imaging to improve hypoxia-induced cognitive impairments. Front Neurosci 2022; 16:955096. [PMID: 36090294 PMCID: PMC9462417 DOI: 10.3389/fnins.2022.955096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
Hypoxic conditions at high altitudes severely affect cognitive functions such as vigilance, attention, and memory and reduce cognitive ability. Hence, there is a critical need to investigate methods and associated mechanisms for improving the cognitive ability of workers at high altitudes. This study aimed to use transcranial direct current stimulation (tDCS) to modulate thalamic network functional connectivity to enhance cognitive ability. We recruited 20 healthy participants that underwent hypoxia exposure in a hypoxic chamber at atmospheric pressure to simulate a hypoxic environment at 4,000 m. Participants received both sham and real stimulation. tDCS significantly improved the participants’ emotional status, including depression, fatigue, and energy level. These effects were sustained for more than 6 h (P < 0.05 at the second to fifth measurements). In addition, tDCS enhanced vigilance, but this was only effective within 2 h (P < 0.05 at the second and third measurements). Central fatigue was significantly ameliorated, and cerebral blood oxygen saturation was increased within 4 h (P < 0.05 at the second, third, and fourth measurements). Furthermore, functional connectivity results using the thalamus as a seed revealed enhanced connectivity between the thalamus and hippocampus, cingulate gyrus, and amygdala after tDCS. These results indicated that tDCS increased local cerebral blood oxygen saturation and enhanced thalamic network connectivity in a hypoxic environment, thereby improving vigilance, depression, fatigue, and energy levels. These findings suggest that tDCS may partially rescue the cognitive decline caused by hypoxia within a short period. This approach affords a safe and effective cognitive enhancement method for all types of high-altitude workers with a large mental load.
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de Brito Aranha REL, Torro-Alves N, Andrade SM, de Oliveira EA, da Silva BNV, da Fonseca ÉKG, Lima dos Santos GE, Guedes NM, dos Santos Falcão Silva T, Fernández-Calvo B. Effects on pain and cognition of transcranial direct current stimulation over the dorsolateral prefrontal cortex in women with chronic migraine. Neurophysiol Clin 2022; 52:333-338. [DOI: 10.1016/j.neucli.2022.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 07/13/2022] [Accepted: 07/13/2022] [Indexed: 11/25/2022] Open
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Effect of anodal high-definition transcranial direct current stimulation on the pain sensitivity in a healthy population: a double-blind, sham-controlled study. Pain 2021; 162:1659-1668. [PMID: 33449508 DOI: 10.1097/j.pain.0000000000002187] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 12/30/2020] [Indexed: 02/07/2023]
Abstract
ABSTRACT High-definition transcranial direct current stimulation (HD-tDCS) of brain areas related to pain processing may provide analgesic effects evident in the sensory detection and pain thresholds. The somatosensory sensitivity was assessed after HD-tDCS targeting the primary motor cortex (M1) and/or the dorsolateral prefrontal cortex (DLPFC). Eighty-one (40 females) subjects were randomly assigned to 1 of 4 anodal HD-tDCS protocols (20 minutes) applied on 3 consecutive days: Sham-tDCS, DLPFC-tDCS, M1-tDCS, and DLPFC&M1-tDCS (simultaneous transcranial direct current stimulation [tDCS] of DLPFC and M1). Subjects and experimenter were blinded to the tDCS protocols. The somatosensory sensitivity were assessed each day, before and after each tDCS by detection and pain thresholds to thermal and mechanical skin stimulation, vibration detection thresholds, and pressure pain thresholds. Subjects were effectively blinded to the protocol, with no significant difference in rates of whether they received real or placebo tDCS between the 4 groups. Compared with the Sham-tDCS, none of the active HD-tDCS protocols caused significant changes in detection or pain thresholds. Independent of tDCS protocols, pain and detection thresholds except vibration detection were increased immediately after the first tDCS protocol compared with baseline (P < 0.05). Overall, the active stimulation protocols were not able to induce significant modulation of the somatosensory thresholds in this healthy population compared with sham-tDCS. Unrelated to the HD-tDCS protocol, a decreased sensitivity was found after the first intervention, indicating a placebo effect or possible habituation to the quantitative sensory testing assessments. These findings add to the increasing literature of null findings in the modulatory effects of HD-tDCS on the healthy somatosensory system.
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13
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Small Enhancement of Bimanual Typing Performance after 20 Sessions of tDCS in Healthy Young Adults. Neuroscience 2021; 466:26-35. [PMID: 33974964 DOI: 10.1016/j.neuroscience.2021.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/04/2021] [Accepted: 05/02/2021] [Indexed: 01/10/2023]
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that may improve motor learning. However, the long-term effects of tDCS have not been explored, and the ecological validity of the evaluated tasks was limited. To determine whether 20 sessions of tDCS over the primary motor cortex (M1) would enhance the performance of a complex life motor skill, i.e., typing, in healthy young adults. Healthy young adults (n = 60) were semi-randomly assigned to three groups: the tDCS group (n = 20) received anodal tDCS over M1; the SHAM group (n = 20) received sham tDCS, both while performing a typing task; and the Control group (CON, n = 20) only performed the typing task. Typing speed and errors at maximum (mTT) and submaximal (iTT) speeds were measured before training, and after 10 and 20 sessions of tDCS. Every subject increased maximum typing speed after 10 and 20 tDCS sessions, with no significant differences (p > 0.05) between the groups. The number of errors at submaximal rates decreased significantly (p < 0.05) by 4% after 10 tDCS sessions compared with the 3% increase in the SHAM and the 2% increase in the CON groups. Between the 10th and 20th tDCS sessions, the number of typing errors increased significantly in all groups. While anodal tDCS reduced typing errors marginally, such performance-enhancing effects plateaued after 10 sessions without any further improvements in typing speed. These findings suggest that long-term tDCS may not have functionally relevant effects on healthy young adults' typing performance.
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14
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Pinheiro Barcessat AR, Nolli Bittencourt M, Góes Gonçalves R, Goncalves de Oliveira Cruz AV, Coelho Pereira JA, Bechelli FA, Rinaldi A. REAC Neuromodulation Treatments in Depression, Anxiety and Stress. A Comparative Retrospective Study. Psychol Res Behav Manag 2020; 13:1247-1256. [PMID: 33376420 PMCID: PMC7762445 DOI: 10.2147/prbm.s287143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/05/2020] [Indexed: 12/16/2022] Open
Abstract
Introduction The purpose of this retrospective study was to compare the effects of two different modalities of administration of the neuro psycho physical optimization (NPPO) neuromodulation treatment, applied with radio electric asymmetric conveyer (REAC) biotechnology devices. Both the modalities are aimed at improving the strategies to deal with and optimize the allostatic response to environmental stressors and exposome. This allows to reduce the dysfunctional adaptive behavior patterns, which underlie many neuropsychological symptoms and pathologies, and to improve the symptoms of depression, anxiety and stress. Materials and Methods From a population of subjects experiencing at least two of the three symptoms depression, anxiety and stress, the selection of pre and post-treatment Depression, Anxiety, Stress 21 items scale (DASS 21) data was made proceeding with a reverse chronological recruitment mechanism, until reaching 150 subjects for each of the 2 groups. The first group was treated with the neuro psycho physical optimization treatment (NPPO), which is the punctiform modality of administration on the auricle pavilion, and the second group was treated with the neuro psycho physical optimization treatment, which is the area modality of administration applied by the planar probe on the cervicobrachial area (NPPO-CB). Results The Wilcoxon signs test confirmed the differences in scores in pre and post-treatment DASS-21. The comparison between the two groups data and the comparison across groups data showed that NPPO and NPPO-CB have the same efficacy in reducing the symptoms of depression, anxiety and stress, after a single treatment cycle. Statistical significance was set at p <0.05. Discussion This is the first efficacy descriptive comparison between the two different modalities of administration of the NPPO treatment, as different options for the same clinical indication.
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Affiliation(s)
| | | | - Rebeca Góes Gonçalves
- Health and Biological Sciences Department, Federal University of Amapá, Macapá, Brazil
| | | | | | - Fabio Augusto Bechelli
- International Scientific Society of Neuro Psycho Physical Optimization with REAC Technology, Brazilian Branch, São Paulo, Brazil
| | - Arianna Rinaldi
- Research Department, Rinaldi Fontani Foundation, Florence, Italy.,Department of Neuro Psycho Physio Pathology and Neuro Psycho Physical Optimization, Rinaldi Fontani Institute, Florence, Italy
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15
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Ehrhardt SE, Filmer HL, Wards Y, Mattingley JB, Dux PE. The influence of tDCS intensity on decision-making training and transfer outcomes. J Neurophysiol 2020; 125:385-397. [PMID: 33174483 DOI: 10.1152/jn.00423.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) has been shown to improve single- and dual-task performance in healthy participants and enhance transferable training gains following multiple sessions of combined stimulation and task practice. However, it has yet to be determined what the optimal stimulation dose is for facilitating such outcomes. We aimed to test the effects of different tDCS intensities, with a commonly used electrode montage, on performance outcomes in a multisession single/dual-task training and transfer protocol. In a preregistered study, 123 participants, who were pseudorandomized across four groups, each completed six sessions (pre- and posttraining sessions and four combined tDCS and training sessions) and received 20 min of prefrontal anodal tDCS at 0.7, 1.0, or 2.0 mA or 15-s sham stimulation. Response time and accuracy were assessed in trained and untrained tasks. The 1.0-mA group showed substantial improvements in single-task reaction time and dual-task accuracy, with additional evidence for improvements in dual-task reaction times, relative to sham performance. This group also showed near transfer to the single-task component of an untrained multitasking paradigm. The 0.7- and 2.0-mA intensities varied in which performance measures they improved on the trained task, but in sum, the effects were less robust than for the 1.0-mA group, and there was no evidence for the transfer of performance. Our study highlights that training performance gains are augmented by tDCS, but their magnitude and nature are not uniform across stimulation intensity.NEW & NOTEWORTHY Using techniques such as transcranial direct current stimulation to modulate cognitive performance is an alluring endeavor. However, the optimal parameters to augment performance are unknown. Here, in a preregistered study with a large sample (123 subjects), three different stimulation dosages (0.7, 1.0, and 2.0 mA) were applied during multitasking training. Different cognitive training performance outcomes occurred across the dosage conditions, with only one of the doses (1.0 mA) leading to training transfer.
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Affiliation(s)
- Shane E Ehrhardt
- School of Psychology, The University of Queensland, St. Lucia, Australia
| | - Hannah L Filmer
- School of Psychology, The University of Queensland, St. Lucia, Australia
| | - Yohan Wards
- School of Psychology, The University of Queensland, St. Lucia, Australia
| | - Jason B Mattingley
- School of Psychology, The University of Queensland, St. Lucia, Australia.,Queensland Brain Institute, The University of Queensland, St. Lucia, Australia.,Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | - Paul E Dux
- School of Psychology, The University of Queensland, St. Lucia, Australia
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16
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Ciullo V, Spalletta G, Caltagirone C, Banaj N, Vecchio D, Piras F, Piras F. Transcranial Direct Current Stimulation and Cognition in Neuropsychiatric Disorders: Systematic Review of the Evidence and Future Directions. Neuroscientist 2020; 27:285-309. [PMID: 32644874 DOI: 10.1177/1073858420936167] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Transcranial direct current stimulation (tDCS) has been implemented in neuropsychiatric disorders characterized by cognitive impairment. However, methodological heterogeneity challenges conclusive remarks. Through a critical analysis of previous conflicting findings and in the light of current neurobiological models of pathophysiology, we qualitatively assessed the effects of tDCS in neuropsychiatric disorders that share neurobiological underpinnings, as to evaluate whether stimulation can improve cognitive deficits in patients' cohorts. We performed a systematic review of tDCS studies targeting cognitive functions in mental disorders and pathological cognitive aging. Data from 41 studies, comprising patients with diagnosis of mood disorders, schizophrenia-spectrum disorders, Alzheimer's disease (AD), and mild cognitive impairment (MCI), were included. Results indicate that tDCS has the capacity to enhance processing speed, working memory, and executive functions in patients with mood and schizophrenia-spectrum disorders. The evidence of a positive effect on general cognitive functioning and memory is either inconclusive in AD, or weak in MCI. Future directions are discussed for developing standardized stimulation protocols and for translating the technique therapeutic potential into effective clinical practice.
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Affiliation(s)
- Valentina Ciullo
- Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Gianfranco Spalletta
- Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy.,Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Carlo Caltagirone
- Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Nerisa Banaj
- Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Daniela Vecchio
- Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Fabrizio Piras
- Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Federica Piras
- Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy
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17
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Investigating the influence of paired-associative stimulation on multi-session skill acquisition and retention in older adults. Clin Neurophysiol 2020; 131:1497-1507. [DOI: 10.1016/j.clinph.2020.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/19/2020] [Accepted: 04/13/2020] [Indexed: 12/26/2022]
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18
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Pellegrini M, Zoghi M, Jaberzadeh S. The effects of transcranial direct current stimulation on corticospinal and cortico-cortical excitability and response variability: Conventional versus high-definition montages. Neurosci Res 2020; 166:12-25. [PMID: 32610058 DOI: 10.1016/j.neures.2020.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 01/19/2023]
Abstract
Response variability following transcranial direct current stimulation (tDCS) highlights need for exploring different tDCS electrode montages. Corticospinal excitability (CSE), cortico-cortical excitability and intra-individual variability was compared following conventional and high-definition (HD) anodal (a-tDCS) and cathodal (c-tDCS) tDCS. Fifteen healthy males attended four sessions at-least one-week apart: conventional a-tDCS, conventional c-tDCS, HD-a-tDCS, HD-c-tDCS. TDCS was administered (1 mA, 10-minutes) over primary motor cortex (M1), via 6 × 4 cm active and 7 × 5 cm return electrodes (conventional tDCS) and 4 × 1 ring-electrodes 3.5 cm apart over M1 (HD-tDCS). For CSE, twenty-five single-pulse transcranial magnetic stimulation (TMS) peak-to-peak motor evoked potentials (MEP) were recorded at baseline, 0-minutes and 30-minutes post-tDCS. Twenty-five paired-pulse MEPs with 3-millisecond (ms) inter-pulse interval (IPI) and twenty-five at 10 ms assessed short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). MEP standardised z-values standard deviations represented intra-individual variability. No significant changes in CSE from baseline were reported for all four interventions. No significant differences were reported in CSE between conventional and HD a-tDCS, but significant differences between conventional and HD c-tDCS 0-minutes post-tDCS. Conventional tDCS significantly reduced intra-individual variability compared to HD-tDCS for a-tDCS (0-minutes) and c-tDCS (30-minutes). No changes were reported for SICI/ICF. These novel findings of increased intra-individual variability following HD-tDCS, at the current stimulus parameters, highlight need for further nuanced research and refinement to optimise the HD-tDCS dosage-response relationship.
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Affiliation(s)
- Michael Pellegrini
- Non-Invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia.
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, School of Allied Health, Discipline of Physiotherapy, La Trobe University, Melbourne, Australia
| | - Shapour Jaberzadeh
- Non-Invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
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19
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Effect of multi-session prefrontal transcranial direct current stimulation on cognition in schizophrenia: A systematic review and meta-analysis. Schizophr Res 2020; 216:367-373. [PMID: 31822431 DOI: 10.1016/j.schres.2019.11.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 12/21/2022]
Abstract
Patients with schizophrenia experience cognitive deficits that play a central role in predicting functional outcomes. In this study, we sought to evaluate the effect of transcranial direct current stimulation (tDCS) on cognition using meta-analysis. A search was performed from inception to 8 January 2019, to identify randomized controlled trials assessing the ability of tDCS to ameliorate cognitive deficits in patients with schizophrenia and schizoaffective disorder. The effect size, calculated as the standardized mean difference (Hedge's g), was obtained with a random effect model. We analyzed mean effects on specific cognitive domains that were evaluated in four or more studies. Nine articles were included in the systematic review, which encompassed 270 patients: 133 in the active stimulation group and 137 in the sham stimulation group. Meta-analysis demonstrated a significant mean effect of tDCS on working memory (SMD = 0.49, 95% CI = 0.16 to 0.83), while non-significant results were produced for other domains. These findings were supported by sensitivity analyses indicating that the results would not change in a meaningful way after the exclusion of each single study, and meta-regression analyses verifying the consistent effect irrespective of any moderators. Thus, tDCS may provide a potential option to improve working memory deficits in individuals with schizophrenia. Further trials examining the cognitive benefit of tDCS with medication or other adjunctive treatments are warranted.
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20
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Debarnot U, Neveu R, Samaha Y, Saruco E, Macintyre T, Guillot A. Acquisition and consolidation of implicit motor learning with physical and mental practice across multiple days of anodal tDCS. Neurobiol Learn Mem 2019; 164:107062. [PMID: 31377178 DOI: 10.1016/j.nlm.2019.107062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 07/16/2019] [Accepted: 07/30/2019] [Indexed: 11/25/2022]
Abstract
BACKGROUND Acquisition and consolidation of a new motor skill occurs gradually over long time span. Motor imagery (MI) and brain stimulation have been showed as beneficial approaches that boost motor learning, but little is known about the extent of their combined effects. OBJECTIVE Here, we aimed to investigate, for the first time, whether delivering multiple sessions of transcranial direct current stimulation (tDCS) over primary motor cortex during physical and MI practice might improve implicit motor sequence learning in a young population. METHODS Participants practiced a serial reaction time task (SRTT) either physically or through MI, and concomitantly received either an anodal (excitatory) or sham stimulation over the primary motor cortex during three successive days. The effect of anodal tDCS on the general motor skill and sequence specific learning were assessed on both acquisition (within-day) and consolidation (between-day) processes. We further compared the magnitude of motor learning reached after a single and three daily sessions of tDCS. RESULTS The main finding showed that anodal tDCS boosted MI practice, but not physical practice, during the first acquisition session. A second major result showed that compared to sham stimulation, multiple daily session of anodal tDCS, for both types of practice, resulted in greater implicit motor sequence learning rather than a single session of stimulation. CONCLUSIONS The present study is of particular importance in the context of rehabilitation, where we postulate that scheduling mental training when patients are not able to perform physical movement might beneficiate from concomitant and consecutive brain stimulation sessions over M1 to promote functional recovery.
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Affiliation(s)
- Ursula Debarnot
- Inter-University Laboratory of Human Movement Biology-EA 7424, University of Lyon, University Claude Bernard Lyon 1, 69 622 Villeurbanne, France.
| | - Rémi Neveu
- Division of Child and Adolescent Psychiatry, University of Geneva, 1200 Geneva, Switzerland
| | - Yvette Samaha
- Inter-University Laboratory of Human Movement Biology-EA 7424, University of Lyon, University Claude Bernard Lyon 1, 69 622 Villeurbanne, France
| | - Elodie Saruco
- Inter-University Laboratory of Human Movement Biology-EA 7424, University of Lyon, University Claude Bernard Lyon 1, 69 622 Villeurbanne, France; Neurologische Universitätsklinik, Bergmannsheil gGmbH, Forschungsgruppe Plastizität, Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany
| | - Tadhg Macintyre
- Health Research Institute, University of Limerick, V94 T9PX Limerick, Ireland
| | - Aymeric Guillot
- Inter-University Laboratory of Human Movement Biology-EA 7424, University of Lyon, University Claude Bernard Lyon 1, 69 622 Villeurbanne, France
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21
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Transcranial Direct Current Stimulation Improves Cognitive Function in Mild to Moderate Alzheimer Disease. Alzheimer Dis Assoc Disord 2019; 33:170-178. [DOI: 10.1097/wad.0000000000000304] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Proton Magnetic Resonance Spectroscopy of the motor cortex reveals long term GABA change following anodal Transcranial Direct Current Stimulation. Sci Rep 2019; 9:2807. [PMID: 30808895 PMCID: PMC6391486 DOI: 10.1038/s41598-019-39262-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/15/2019] [Indexed: 12/22/2022] Open
Abstract
Anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has been reported to increase the firing rates of neurons and to modulate the gamma-aminobutyric acid (GABA) concentration. To date, knowledge about the nature and duration of these tDCS induced effects is incomplete. We aimed to investigate long-term effects of anodal tDCS over M1 on GABA dynamics in humans. Repeated magnetic resonance spectroscopy (MRS) was employed to measure relative GABA concentration in M1 for approximately 64 minutes after stimulation. The study was performed on 32 healthy subjects. Either anodal or sham tDCS were applied for 10 minutes with the active electrode over the left M1 and the reference electrode over the right supra-orbital region. Pre and post-tDCS MRS scans were performed to acquire GABA-edited spectra using 3 T Prisma Siemens scanner. GABA signals showed no change over time in the sham tDCS group, whereas anodal tDCS resulted in a significant early decrease within 25 minutes after tDCS and then significant late decrease after 66 minutes which continued until the last test measurements. The late changes in GABA concentration might be related to long-term plasticity mechanism. These results contribute to a better understanding of the neurochemical mechanism underlying long-term cortical plasticity following anodal tDCS.
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23
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Dumel G, Bourassa ME, Charlebois-Plante C, Desjardins M, Doyon J, Saint-Amour D, De Beaumont L. Motor Learning Improvement Remains 3 Months After a Multisession Anodal tDCS Intervention in an Aging Population. Front Aging Neurosci 2018; 10:335. [PMID: 30405402 PMCID: PMC6207687 DOI: 10.3389/fnagi.2018.00335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/04/2018] [Indexed: 01/04/2023] Open
Abstract
Healthy aging is associated with decline of motor function that can generate serious consequences on the quality of life and safety. Our studies aim to explore the 3-month effects of a 5-day multisession anodal transcranial direct current stimulation (a-tDCS) protocol applied over the primary motor cortex (M1) during motor sequence learning in elderly. The present sham-controlled aging study investigated whether tDCS-induced motor improvements previously observed 1 day after the intervention persist beyond 3 months. A total of 37 cognitively-intact aging participants performed five consecutive daily 20-min sessions of the serial-reaction time task (SRTT) concomitant with either anodal (n = 18) or sham (n = 19) tDCS over M1. All participants performed the Purdue Pegboard Test and transcranial magnetic stimulation (TMS) measures of cortical excitability were collected before, 1 day after and 3 months after the intervention. The last follow-up session also included the execution of the trained SRTT. The main findings are the demonstration of durable effects of a 5-day anodal tDCS intervention at the trained skill, while the active intervention did not differ from the sham intervention at both the untrained task and on measures of M1-disinhibition. Thus, the current article revealed for the first time the durability of functional effects of a-tDCS combined with motor training after only 5 days of intervention in an aging population. This finding provides evidence that the latter treatment alternative is effective in achieving our primary motor rehabilitation goal, that is to allow durable motor training effects in an aging population.
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Affiliation(s)
- Gaëlle Dumel
- Centre de Recherche de l'Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada.,Département de Psychologie, Université du Québec à Montréal, Montréal, QC, Canada
| | - Marie-Eve Bourassa
- Centre de Recherche de l'Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada.,Département de Psychologie, Université du Québec à Montréal, Montréal, QC, Canada
| | | | - Martine Desjardins
- Centre de Recherche de l'Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada.,Département de Psychologie, Université du Québec à Montréal, Montréal, QC, Canada
| | - Julien Doyon
- Unité de Neuroimagerie Fonctionnelle, Centre de Recherche de l'Institut de Gériatrie de Montréal, Montréal, QC, Canada
| | - Dave Saint-Amour
- Département de Psychologie, Université du Québec à Montréal, Montréal, QC, Canada
| | - Louis De Beaumont
- Centre de Recherche de l'Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada.,Département de Chirurgie, Université de Montréal, Montréal, QC, Canada
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24
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Thair H, Holloway AL, Newport R, Smith AD. Transcranial Direct Current Stimulation (tDCS): A Beginner's Guide for Design and Implementation. Front Neurosci 2017; 11:641. [PMID: 29213226 PMCID: PMC5702643 DOI: 10.3389/fnins.2017.00641] [Citation(s) in RCA: 248] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 11/06/2017] [Indexed: 12/22/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) is a popular brain stimulation method that is used to modulate cortical excitability, producing facilitatory or inhibitory effects upon a variety of behaviors. There is, however, a current lack of consensus between studies, with many results suggesting that polarity-specific effects are difficult to obtain. This article explores some of these differences and highlights the experimental parameters that may underlie their occurrence. We provide a general, practical snapshot of tDCS methodology, including what it is used for, how to use it, and considerations for designing an effective and safe experiment. Our aim is to equip researchers who are new to tDCS with the essential knowledge so that they can make informed and well-rounded decisions when designing and running successful experiments. By summarizing the varied approaches, stimulation parameters, and outcomes, this article should help inform future tDCS research in a variety of fields.
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Affiliation(s)
- Hayley Thair
- School of Psychology, University of Nottingham, Nottingham, United Kingdom
| | - Amy L Holloway
- School of Psychology, University of Nottingham, Nottingham, United Kingdom
| | - Roger Newport
- School of Psychology, University of Nottingham, Nottingham, United Kingdom
| | - Alastair D Smith
- School of Psychology, University of Nottingham, Nottingham, United Kingdom.,School of Psychology, University of Plymouth, Plymouth, United Kingdom
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25
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Dissanayaka T, Zoghi M, Farrell M, Egan GF, Jaberzadeh S. Does transcranial electrical stimulation enhance corticospinal excitability of the motor cortex in healthy individuals? A systematic review and meta-analysis. Eur J Neurosci 2017; 46:1968-1990. [DOI: 10.1111/ejn.13640] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 07/03/2017] [Accepted: 07/04/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Thusharika Dissanayaka
- Department of Physiotherapy; School of Primary Health Care; Faculty of Medicine; Nursing and Health Sciences; Monash University; Melbourne Victoria Australia
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport; School of Allied Health; La Trobe University; Bundoora Victoria Australia
| | - Michael Farrell
- Monash Biomedical Imaging; Monash University; Melbourne Victoria Australia
- Biomedicine Discovery Institute and Department of Medical Imaging and Radiation Sciences; Monash University; Melbourne Victoria Australia
| | - Gary F. Egan
- Monash Biomedical Imaging; Monash University; Melbourne Victoria Australia
| | - Shapour Jaberzadeh
- Department of Physiotherapy; School of Primary Health Care; Faculty of Medicine; Nursing and Health Sciences; Monash University; Melbourne Victoria Australia
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26
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Yavari F, Nitsche MA, Ekhtiari H. Transcranial Electric Stimulation for Precision Medicine: A Spatiomechanistic Framework. Front Hum Neurosci 2017; 11:159. [PMID: 28450832 PMCID: PMC5390027 DOI: 10.3389/fnhum.2017.00159] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/17/2017] [Indexed: 12/11/2022] Open
Abstract
During recent years, non-invasive brain stimulation, including transcranial electrical stimulation (tES) in general, and transcranial direct current stimulation (tDCS) in particular, have created new hopes for treatment of neurological and psychiatric diseases. Despite promising primary results in some brain disorders, a more widespread application of tES is hindered by the unsolved question of determining optimum stimulation protocols to receive meaningful therapeutic effects. tES has a large parameter space including various montages and stimulation parameters. Moreover, inter- and intra-individual differences in responding to stimulation protocols have to be taken into account. These factors contribute to the complexity of selecting potentially effective protocols for each disorder, different clusters of each disorder, and even each single patient. Expanding knowledge in different dimensions of basic and clinical neuroscience could help researchers and clinicians to select potentially effective protocols based on tES modulatory mechanisms for future clinical studies. In this article, we propose a heuristic spatiomechanistic framework which contains nine levels to address tES effects on brain functions. Three levels refer to the spatial resolution (local, small-scale networks and large-scale networks) and three levels of tES modulatory effects based on its mechanisms of action (neurochemical, neuroelectrical and oscillatory modulations). At the group level, this framework could be helpful to enable an informed and systematic exploration of various possible protocols for targeting a brain disorder or its neuroscience-based clusters. Considering recent advances in exploration of neurodiversity at the individual level with different brain mapping technologies, the proposed framework might also be used in combination with personal data to design individualized protocols for tES in the context of precision medicine in the future.
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Affiliation(s)
- Fatemeh Yavari
- Department of Psychology and Neuroscience, Leibniz Research Centre for Working Environment and Human FactorsDortmund, Germany
| | - Michael A. Nitsche
- Department of Psychology and Neuroscience, Leibniz Research Centre for Working Environment and Human FactorsDortmund, Germany
- Department of Neurology, University Medical Hospital BergmannsheilBochum, Germany
| | - Hamed Ekhtiari
- Neurocognitive Laboratory, Iranian National Center for Addiction Studies (INCAS), Tehran University of Medical SciencesTehran, Iran
- Translational Neuroscience Program, Institute for Cognitive Science Studies (ICSS)Tehran, Iran
- Neuroimaging and Analysis Group, Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical SciencesTehran, Iran
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Response variability of different anodal transcranial direct current stimulation intensities across multiple sessions. Brain Stimul 2017; 10:757-763. [PMID: 28420581 DOI: 10.1016/j.brs.2017.04.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 02/01/2017] [Accepted: 04/07/2017] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND It is well known that transcranial direct current stimulation (tDCS) is capable of modulating corticomotor excitability. However, a source of growing concern has been the observed inter- and intra-individual variability of tDCS-responses. Recent studies have assessed whether individuals respond in a predictable manner across repeated sessions of anodal tDCS (atDCS). The findings of these investigations have been inconsistent, and their methods have some limitations (i.e. lack of sham condition or testing only one tDCS intensity). OBJECTIVE To study inter- and intra-individual variability of atDCS effects at two different intensities on primary motor cortex (M1) excitability. METHODS Twelve subjects participated in a crossover study testing 7-min atDCS over M1 in three separate conditions (2 mA, 1 mA, sham) each repeated three times separated by 48 h. Motor evoked potentials were recorded before and after stimulation (up to 30min). Time of testing was maintained consistent within participants. To estimate the reliability of tDCS effects across sessions, we calculated the Intra-class Correlation Coefficient (ICC). RESULTS AtDCS at 2 mA, but not 1 mA, significantly increased cortical excitability at the group level in all sessions. The overall ICC revealed fair to high reliability of tDCS effects for multiple sessions. Given that the distribution of responses showed important variability in the sham condition, we established a Sham Variability-Based Threshold to classify responses and to track individual changes across sessions. Using this threshold an intra-individual consistent response pattern was then observed only for the 2 mA condition. CONCLUSION 2 mA anodal tDCS results in consistent intra- and inter-individual increases of M1 excitability.
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Optimizing Transcranial Direct Current Stimulation Protocols to Promote Long-Term Learning. JOURNAL OF COGNITIVE ENHANCEMENT 2017. [DOI: 10.1007/s41465-017-0007-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Spampinato D, Celnik P. Temporal dynamics of cerebellar and motor cortex physiological processes during motor skill learning. Sci Rep 2017; 7:40715. [PMID: 28091578 PMCID: PMC5238434 DOI: 10.1038/srep40715] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 12/08/2016] [Indexed: 11/30/2022] Open
Abstract
Learning motor tasks involves distinct physiological processes in the cerebellum (CB) and primary motor cortex (M1). Previous studies have shown that motor learning results in at least two important neurophysiological changes: modulation of cerebellar output mediated in-part by long-term depression of parallel fiber-Purkinje cell synapse and induction of long-term plasticity (LTP) in M1, leading to transient occlusion of additional LTP-like plasticity. However, little is known about the temporal dynamics of these two physiological mechanisms during motor skill learning. Here we use non-invasive brain stimulation to explore CB and M1 mechanisms during early and late motor skill learning in humans. We predicted that early skill acquisition would be proportional to cerebellar excitability (CBI) changes, whereas later stages of learning will result in M1 LTP-like plasticity modifications. We found that early, and not late into skill training, CBI changed. Whereas, occlusion of LTP-like plasticity over M1 occurred only during late, but not early training. These findings indicate a distinct temporal dissociation in the physiological role of the CB and M1 when learning a novel skill. Understanding the role and temporal dynamics of different brain regions during motor learning is critical to device optimal interventions to augment learning.
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Affiliation(s)
- D Spampinato
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, 720 Rutland Avenue Baltimore, MD 21205, USA.,Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, 600 North Wolfe Street Baltimore, MD 21287, USA
| | - P Celnik
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, 600 North Wolfe Street Baltimore, MD 21287, USA.,Department of Neuroscience, Johns Hopkins School of Medicine, 725 North Wolfe Street Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins School of Medicine, 600 North Wolfe Street Baltimore, MD 21287, USA
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Reinhart RMG, Cosman JD, Fukuda K, Woodman GF. Using transcranial direct-current stimulation (tDCS) to understand cognitive processing. Atten Percept Psychophys 2017; 79:3-23. [PMID: 27804033 PMCID: PMC5539401 DOI: 10.3758/s13414-016-1224-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Noninvasive brain stimulation methods are becoming increasingly common tools in the kit of the cognitive scientist. In particular, transcranial direct-current stimulation (tDCS) is showing great promise as a tool to causally manipulate the brain and understand how information is processed. The popularity of this method of brain stimulation is based on the fact that it is safe, inexpensive, its effects are long lasting, and you can increase the likelihood that neurons will fire near one electrode and decrease the likelihood that neurons will fire near another. However, this method of manipulating the brain to draw causal inferences is not without complication. Because tDCS methods continue to be refined and are not yet standardized, there are reports in the literature that show some striking inconsistencies. Primary among the complications of the technique is that the tDCS method uses two or more electrodes to pass current and all of these electrodes will have effects on the tissue underneath them. In this tutorial, we will share what we have learned about using tDCS to manipulate how the brain perceives, attends, remembers, and responds to information from our environment. Our goal is to provide a starting point for new users of tDCS and spur discussion of the standardization of methods to enhance replicability.
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Affiliation(s)
- Robert M G Reinhart
- Department of Psychological and Brain Sciences, Center for Research in Sensory Communications and Neural Technology, Center for Systems Neuroscience, Boston University, Boston, MA, 02215, USA.
| | - Josh D Cosman
- Department of Translational Medicine, Pfizer Inc., Cambridge, MA, 02215, USA
| | - Keisuke Fukuda
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Geoffrey F Woodman
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN, 37240, USA.
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Reliability and Variability of tDCS Induced Changes in the Lower Limb Motor Cortex. Brain Sci 2016; 6:brainsci6030026. [PMID: 27472368 PMCID: PMC5039455 DOI: 10.3390/brainsci6030026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/15/2016] [Accepted: 07/25/2016] [Indexed: 11/21/2022] Open
Abstract
Background: Transcranial direct current stimulation (tDCS) is emerging as a promising adjuvant to enhance motor function. However, there has been increasing reservations about the reliability and variability of the neuromodulatory effects evoked by tDCS. Objective/Hypothesis: The main purpose of this study was to explore the test-retest reliability and inter-individual variability of tDCS of the lower limb M1 and the relationship between transcranial magnetic stimulation (TMS)-related measures and tDCS-induced changes. Methods: Fifteen healthy participants received anodal tDCS of the lower limb M1 either when performing a lower limb motor task or when the limb was at rest. Each condition was tested twice. tDCS induced changes in corticomotor excitability of the tibialis anterior muscle were measured using TMS. A repeated measures ANOVA was performed to examine efficacy of tDCS between the two task conditions. Intraclass correlation coefficients (ICC) and variance component analyses were performed to examine reliability and variability respectively. Results: A significant increase in in corticomotor excitability was noted for the tDCS-task condition at 140% active motor threshold (AMT) and when comparing recruitment curve slopes, but not at 120% and 130% AMT. Overall, ICC values between testing days for each stimulation condition ranged from 0.6–0.9. Higher ICCs were seen for higher TMS intensities (140% AMT) and recruitment curve slopes. Inter-individual variability contributed to 34% of the exhibited variance. Conclusions: Our data suggest that the TMS-related measure used to assess neuromodulation after tDCS has an effect on its perceived test-retest reliability and inter-individual variability. Importantly, we noticed that a high reliability and low variability does not necessarily indicate clinical efficacy of tDCS as some participants showed little to no modulation of corticomotor excitability consistently.
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Multisession Anodal tDCS Protocol Improves Motor System Function in an Aging Population. Neural Plast 2016; 2016:5961362. [PMID: 26881118 PMCID: PMC4736991 DOI: 10.1155/2016/5961362] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/17/2015] [Accepted: 11/22/2015] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES The primary objective of this study was to investigate the effects of five consecutive, daily 20-minute sessions of M1 a-tDCS on motor learning in healthy, cognitively intact, aging adults. DESIGN A total of 23 participants (51 to 69 years old) performed five consecutive, daily 20-minute sessions of a serial reaction time task (SRT task) concomitant with either anodal (n = 12) or sham (n = 11) M1 a-tDCS. RESULTS We found a significant group × training sessions interaction, indicating that whereas aging adults in the sham group exhibited little-to-no sequence-specific learning improvements beyond the first day of training, reproducible improvements in the ability to learn new motor sequences over 5 consecutive sessions were the net result in age-equivalent participants from the M1 a-tDCS group. A significant main effect of group on sequence-specific learning revealed greater motor learning for the M1 a-tDCS group when the five learning sessions were averaged. CONCLUSION These findings raise into prominence the utility of multisession anodal TDCS protocols in combination with motor training to help prevent/alleviate age-associated motor function decline.
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Ho KA, Taylor JL, Chew T, Gálvez V, Alonzo A, Bai S, Dokos S, Loo CK. The Effect of Transcranial Direct Current Stimulation (tDCS) Electrode Size and Current Intensity on Motor Cortical Excitability: Evidence From Single and Repeated Sessions. Brain Stimul 2015; 9:1-7. [PMID: 26350410 DOI: 10.1016/j.brs.2015.08.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 08/03/2015] [Accepted: 08/10/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Current density is considered an important factor in determining the outcomes of tDCS, and is determined by the current intensity and electrode size. Previous studies examining the effect of these parameters on motor cortical excitability with small sample sizes reported mixed results. OBJECTIVE/HYPOTHESIS This study examined the effect of current intensity (1 mA, 2 mA) and electrode size (16 cm(2), 35 cm(2)) on motor cortical excitability over single and repeated tDCS sessions. METHODS Data from seven studies in 89 healthy participants were pooled for analysis. Single-session data were analyzed using mixed effects models and repeated-session data were analyzed using mixed design analyses of variance. Computational modeling was used to examine the electric field generated. RESULTS The magnitude of increases in excitability after anodal tDCS was modest. For single-session tDCS, the 35 cm(2) electrodes produced greater increases in cortical excitability compared to the 16 cm(2) electrodes. There were no differences in the magnitude of cortical excitation produced by 1 mA and 2 mA tDCS. The repeated-sessions data also showed that there were greater increases in excitability with the 35 cm(2) electrodes. Further, repeated sessions of tDCS with the 35 cm(2) electrodes resulted in a cumulative increase in cortical excitability. Computational modeling predicted higher electric field at the motor hotspot for the 35 cm(2) electrodes. CONCLUSIONS 2 mA tDCS does not necessarily produce larger effects than 1 mA tDCS in healthy participants. Careful consideration should be given to the exact positioning, size and orientation of tDCS electrodes relative to cortical regions.
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Affiliation(s)
- Kerrie-Anne Ho
- School of Psychiatry, University of New South Wales, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia; Black Dog Institute, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia
| | - Janet L Taylor
- Neuroscience Research Australia, Margarete Ainsworth Building, Barker Street, Randwick, NSW 2031, Australia; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Taariq Chew
- School of Psychiatry, University of New South Wales, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia; Black Dog Institute, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia
| | - Verònica Gálvez
- School of Psychiatry, University of New South Wales, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia; Black Dog Institute, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia
| | - Angelo Alonzo
- School of Psychiatry, University of New South Wales, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia; Black Dog Institute, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia
| | - Siwei Bai
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia; IMETUM, Technische Universität München, Garching 85748, Germany
| | - Socrates Dokos
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Colleen K Loo
- School of Psychiatry, University of New South Wales, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia; Black Dog Institute, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia; St George Hospital, South Eastern Sydney Health, Level 2, James Laws House, Gray St, Kogarah, NSW 2217, Australia.
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Ho KA, Bai S, Martin D, Alonzo A, Dokos S, Puras P, Loo CK. A pilot study of alternative transcranial direct current stimulation electrode montages for the treatment of major depression. J Affect Disord 2015; 167:251-8. [PMID: 24998841 DOI: 10.1016/j.jad.2014.06.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/12/2014] [Accepted: 06/12/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Typically, transcranial direct current stimulation (tDCS) treatments for depression have used bifrontal montages with anodal (excitatory) stimulation targeting the left dorsolateral prefrontal cortex (DLPFC). There is limited research examining the effects of alternative electrode montages. OBJECTIVE/HYPOTHESIS This pilot study aimed to examine the feasibility, tolerability and safety of two alternative electrode montages and provide preliminary data on efficacy. The montages, Fronto-Occipital (F-O) and Fronto-Cerebellar (F-C), were designed respectively to target midline brain structures and the cerebellum. METHODS The anode was placed over the left supraorbital region and the cathode over the occipital and cerebellar region for the F-O and F-C montages respectively. Computational modelling was used to determine the electric fields produced in the brain regions of interest compared to a standard bifrontal montage. The two montages were evaluated in an open label study of depressed participants (N=14). Mood and neuropsychological functioning were assessed at baseline and after four weeks of tDCS. RESULTS Computational modelling revealed that the novel montages resulted in greater activation in the anterior cingulate cortices and cerebellum than the bifrontal montage, while activation of the DLPFCs was higher for the bifrontal montage. After four weeks of tDCS, overall mood improvement rates of 43.8% and 15.9% were observed under the F-O and F-C conditions, respectively. No significant neuropsychological changes were found. LIMITATIONS The clinical pilot was open-label, without a control condition and computational modelling was based on one healthy participant. CONCLUSIONS Results found both montages safe and feasible. The F-O montage showed promising antidepressant potential.
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Affiliation(s)
- Kerrie-Anne Ho
- School of Psychiatry, University of New South Wales, Black Dog Institute, Sydney, NSW 2031, Australia
| | - Siwei Bai
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Donel Martin
- School of Psychiatry, University of New South Wales, Black Dog Institute, Sydney, NSW 2031, Australia
| | - Angelo Alonzo
- School of Psychiatry, University of New South Wales, Black Dog Institute, Sydney, NSW 2031, Australia
| | - Socrates Dokos
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Pablo Puras
- Department of Psychiatry, Hospital Universitario de Getafe, Getafe, Madrid, Spain; School of Psychiatry, University of New South Wales, Black Dog Institute, Sydney, NSW 2031, Australia
| | - Colleen K Loo
- School of Psychiatry, University of New South Wales, Black Dog Institute, Sydney, NSW 2031, Australia; Department of Psychiatry, St George Hospital, Sydney, Australia.
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Player MJ, Taylor JL, Weickert CS, Alonzo A, Sachdev PS, Martin D, Mitchell PB, Loo CK. Increase in PAS-induced neuroplasticity after a treatment course of transcranial direct current stimulation for depression. J Affect Disord 2015; 167:140-7. [PMID: 24968188 DOI: 10.1016/j.jad.2014.05.063] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 05/28/2014] [Accepted: 05/29/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND Several lines of evidence suggest that neuroplasticity is impaired in depression and improves with effective treatment. However until now, this evidence has largely involved measures such as learning and memory which can be influenced by subject effort and motivation. This pilot study aimed to objectively measure neuroplasticity in the motor cortex using paired associative stimulation (PAS), which induces short term neuroplastic changes. It is hypothesized that neuroplasticity would improve after effective treatment for depression. METHODS Neuroplasticity was measured in 18 depressed subjects before and after a course of anodal transcranial direct current stimulation (tDCS), given as treatment for depression. The relationships between PAS results, mood state and brain-derived neurotrophic factor (BDNF) serum levels were examined. RESULTS Neuroplasticity (PAS-induced change) was increased after a course of tDCS (t(17)=-2.651, p=0.017). Treatment with tDCS also led to significant mood improvement, but this did not correlate with improved neuroplasticity. Serum BDNF levels did not change after tDCS, or correlate with change in neuroplasticity after tDCS treatment. LIMITATIONS While this study showed evidence of improved neuroplasticity in the motor cortex after effective treatment, we are unable to present evidence that this change is generalized in the depressed brain. Also, the presence of antidepressant medications and the small sample of patients (n=18) meant the study could not definitively resolve the relationship between neuroplasticity, mood and BDNF. CONCLUSION This novel preliminary study provides evidence that a treatment course of tDCS can improve neuroplasticity in depressed patients.
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Affiliation(s)
- Michael J Player
- School of Psychiatry, University of New South Wales, Sydney, Australia; Black Dog Institute, Hospital Road, Randwick, Sydney, NSW 2031, Australia
| | - Janet L Taylor
- Neuroscience Research Australia, Sydney, Australia; School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Cynthia Shannon Weickert
- School of Psychiatry, University of New South Wales, Sydney, Australia; Neuroscience Research Australia, Sydney, Australia; Schizophrenia Research Institute, Darlinghurst, Sydney, Australia
| | - Angelo Alonzo
- School of Psychiatry, University of New South Wales, Sydney, Australia; Black Dog Institute, Hospital Road, Randwick, Sydney, NSW 2031, Australia
| | - Perminder S Sachdev
- School of Psychiatry, University of New South Wales, Sydney, Australia; Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, Australia; Centre for Healthy Brain Ageing (CHeBA), University of New South Wales, Australia
| | - Donel Martin
- School of Psychiatry, University of New South Wales, Sydney, Australia; Black Dog Institute, Hospital Road, Randwick, Sydney, NSW 2031, Australia
| | - Philip B Mitchell
- School of Psychiatry, University of New South Wales, Sydney, Australia; Black Dog Institute, Hospital Road, Randwick, Sydney, NSW 2031, Australia
| | - Colleen K Loo
- School of Psychiatry, University of New South Wales, Sydney, Australia; Black Dog Institute, Hospital Road, Randwick, Sydney, NSW 2031, Australia; St. George Hospital, South Eastern Sydney Health, Australia.
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Horvath JC, Forte JD, Carter O. Evidence that transcranial direct current stimulation (tDCS) generates little-to-no reliable neurophysiologic effect beyond MEP amplitude modulation in healthy human subjects: A systematic review. Neuropsychologia 2015; 66:213-36. [PMID: 25448853 DOI: 10.1016/j.neuropsychologia.2014.11.021] [Citation(s) in RCA: 347] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 10/25/2014] [Accepted: 11/14/2014] [Indexed: 12/12/2022]
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Martin DM, Liu R, Alonzo A, Green M, Loo CK. Use of transcranial direct current stimulation (tDCS) to enhance cognitive training: effect of timing of stimulation. Exp Brain Res 2014; 232:3345-51. [PMID: 24992897 DOI: 10.1007/s00221-014-4022-x] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 06/17/2014] [Indexed: 11/30/2022]
Abstract
The capacity for transcranial direct current stimulation (tDCS) to increase learning and cognition shows promise for the development of enhanced therapeutic interventions. One potential application is the combination of tDCS with cognitive training (CT), a psychological intervention which aims to improve targeted cognitive abilities. We have previously shown that tDCS enhanced performance accuracy, but not skill acquisition, on a dual n-back working memory (WM) CT task over repeated sessions. In the current study, we investigated the optimal timing for combining tDCS with the same CT task to enhance within and between session performance outcomes across two daily CT sessions. Twenty healthy participants received in a randomised order 30 min of anodal tDCS to the left dorsolateral prefrontal cortex immediately before ('offline' tDCS) and during performance ('online' tDCS) on a dual n-back WM CT task, in an intra-individual crossover design. Analyses examined within and between session consolidation effects of tDCS on CT performance outcomes. Results showed that 'online' tDCS was associated with better within session skill acquisition on the CT task, with a significant difference found between conditions the following day. These results suggest that 'online' tDCS is superior to 'offline' tDCS for enhancing skill acquisition when combining anodal tDCS with CT. This finding may assist with the development of enhanced protocols involving the combination of tDCS with CT and other rehabilitation protocols.
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Affiliation(s)
- Donel M Martin
- Black Dog Institute, School of Psychiatry, Prince of Wales Hospital, University of New South Wales, Barker St, Randwick, Sydney, 2031, Australia,
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Horvath JC, Carter O, Forte JD. Transcranial direct current stimulation: five important issues we aren't discussing (but probably should be). Front Syst Neurosci 2014; 8:2. [PMID: 24478640 PMCID: PMC3901383 DOI: 10.3389/fnsys.2014.00002] [Citation(s) in RCA: 244] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 01/08/2014] [Indexed: 12/12/2022] Open
Abstract
Transcranial Direct Current Stimulation (tDCS) is a neuromodulatory device often publicized for its ability to enhance cognitive and behavioral performance. These enhancement claims, however, are predicated upon electrophysiological evidence and descriptions which are far from conclusive. In fact, a review of the literature reveals a number of important experimental and technical issues inherent with this device that are simply not being discussed in any meaningful manner. In this paper, we will consider five of these topics. The first, inter-subject variability, explores the extensive between- and within-group differences found within the tDCS literature and highlights the need to properly examine stimulatory response at the individual level. The second, intra-subject reliability, reviews the lack of data concerning tDCS response reliability over time and emphasizes the importance of this knowledge for appropriate stimulatory application. The third, sham stimulation and blinding, draws attention to the importance (yet relative lack) of proper control and blinding practices in the tDCS literature. The fourth, motor and cognitive interference, highlights the often overlooked body of research that suggests typical behaviors and cognitions undertaken during or following tDCS can impair or abolish the effects of stimulation. Finally, the fifth, electric current influences, underscores several largely ignored variables (such as hair thickness and electrode attachments methods) influential to tDCS electric current density and flow. Through this paper, we hope to increase awareness and start an ongoing dialog of these important issues which speak to the efficacy, reliability, and mechanistic foundations of tDCS.
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Affiliation(s)
- Jared C. Horvath
- Psychological Sciences, University of MelbourneMelbourne, VIC, Australia
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