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Macedo MDCGS, Ferreira KRDR, Meira PA, Esquírio AF, Barbosa MCSA, Gama GL, Barbosa AWC. Do Progressive Intensities of Transcranial Direct Current Stimulation with and Without 40 Hz Binaural Beats Change Pre-Frontal Cortex Hemodynamics? A Randomized Controlled Trial. Behav Sci (Basel) 2024; 14:1001. [PMID: 39594300 PMCID: PMC11591234 DOI: 10.3390/bs14111001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2024] [Revised: 10/24/2024] [Accepted: 10/25/2024] [Indexed: 11/28/2024] Open
Abstract
Transcranial direct current stimulation (tDCS) is often reported to have positive effects on brain hemodynamics as well as cognitive performance. Binaural beats (BBs) have also shown the potential to improve cognitive performance. However, we could not find any studies assessing prefrontal hemodynamics using a combination of these techniques or assessing the effects on hemodynamic response at different intensity levels of tDCS (two and three mA). This study aimed to compare the immediate hemodynamic responses to tDCS at different intensities (two and three mA) with and without 40 Hz BBs. Sixty-eight healthy young individuals of both sexes were split into four groups: the tDCS 2 mA group; tDCS 3 mA group; tDCS 2 mA + BB group; and tDCS 3 mA + BB group. All groups received 20 min tDCS (F3-Fp2) alone or combined with BBs. The hemodynamic effect was assessed using a functional near-infrared intracranial spectroscope (fNIRS) positioned on the left supraorbital region (Fp1). The mean values of rates of oxygen saturation (SatO2) were recorded at baseline, during the intervention period, and post-stimulation. The oxygenated hemoglobin rates (HbO) were also extracted. No between-group differences were observed. The within-group analysis did not show significant differences in terms of the time×groups factor. However, the time factor showed significant within-group differences. No differences were found for the HbO rates. The present findings showed that two and three mA tDCS had effects on pre-frontal cortex SatO2; however, the use of additional BBs did not change the SatO2 levels compared to the use of tDCS alone.
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Affiliation(s)
| | | | | | | | | | | | - Alexandre Wesley Carvalho Barbosa
- Department of Physical Therapy, Laboratory of Non-Invasive Neuromodulation-LANN, Federal University of Juiz de Fora, Av. Moacir Paleta 1167, Governador Valadares 35010-180, MG, Brazil; (M.d.C.G.S.M.); (K.R.d.R.F.); (P.A.M.); (A.F.E.); (M.C.S.A.B.); (G.L.G.)
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Qi S, Cao L, Wang Q, Sheng Y, Yu J, Liang Z. The Physiological Mechanisms of Transcranial Direct Current Stimulation to Enhance Motor Performance: A Narrative Review. BIOLOGY 2024; 13:790. [PMID: 39452099 PMCID: PMC11504865 DOI: 10.3390/biology13100790] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Revised: 09/28/2024] [Accepted: 09/30/2024] [Indexed: 10/26/2024]
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique that applies a stable, low-intensity (1-2 mA) direct current to modulate neuronal activity in the cerebral cortex. This technique is effective, simple to operate, affordable, and widely employed across various fields. tDCS has been extensively used in clinical and translational research, with growing applications in military and competitive sports domains. In recent years, the use of tDCS in sports science has garnered significant attention from researchers. Numerous studies have demonstrated that tDCS can enhance muscle strength, explosive power, and aerobic metabolism, reduce fatigue, and improve cognition, thereby serving as a valuable tool for enhancing athletic performance. Additionally, recent research has shed light on the physiological mechanisms underlying tDCS, including its modulation of neuronal resting membrane potential to alter cortical excitability, enhancement of synaptic plasticity to regulate long-term potentiation, modulation of neurovascular coupling to improve regional cerebral blood flow, and improvement of cerebral network functional connectivity, which activates and reinforces specific brain regions. tDCS also enhances the release of excitatory neurotransmitters, further regulating brain function. This article, after outlining the role of tDCS in improving physical performance, delves into its mechanisms of action to provide a deeper understanding of how tDCS enhances athletic performance and offers novel approaches and perspectives for physical performance enhancement.
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Affiliation(s)
- Shuo Qi
- School of Sport and Health, Shandong Sport University, Jinan 250102, China; (S.Q.)
| | - Lei Cao
- National Football Academy, Shandong Sport University, Jinan 250102, China
| | - Qingchun Wang
- School of Sport and Health, Shandong Sport University, Jinan 250102, China; (S.Q.)
| | - Yin Sheng
- College of Competitive Sports, Shandong Sport University, Jinan 250102, China
| | - Jinglun Yu
- School of Exercise and Health Sciences, Xi’an Physical Education University, Xi’an 710068, China
| | - Zhiqiang Liang
- Faculty of Sports Science, Ningbo University, Ningbo 315211, China
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Kim J, Park S, Kim H, Roh D, Kim DH. Home-based, Remotely Supervised, 6-Week tDCS in Patients With Both MCI and Depression: A Randomized Double-Blind Placebo-Controlled Trial. Clin EEG Neurosci 2024; 55:531-542. [PMID: 38105601 DOI: 10.1177/15500594231215847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
As depressive symptom is considered a prodrome, a risk factor for progression from mild cognitive impairment (MCI) to dementia, improving depressive symptoms should be considered a clinical priority in patients with MCI undergoing transcranial direct current stimulation (tDCS) intervention. We aimed to comprehensively evaluate the efficacy of the home-based and remotely monitored tDCS in patients with both MCI and depression, by integrating cognitive, psychological, and electrophysiological indicators. In a 6-week, randomized, double blind, and sham-controlled study, 37 community-dwelling patients were randomly assigned to either an active or a sham stimulation group, and received 30 home-based sessions of 2 mA tDCS for 30 min with the anode located over the left and cathode over the right dorsolateral prefrontal cortex. We measured depressive symptoms, neurocognitive function, and resting-state electroencephalography. In terms of effects of both depressive symptoms and cognitive functions, active tDCS was not significantly different from sham tDCS. However, compared to sham stimulation, active tDCS decreased and increased the activation of delta and beta frequencies, respectively. Moreover, the increase in beta activity was correlated with the cognitive enhancement only in the active group. It was not possible to reach a definitive conclusion regarding the efficacy of tDCS on depression and cognition in patients with both MCI and depression. Nevertheless, the relationship between the changes of electrophysiology and cognitive performance suggests potential neuroplasticity enhancement implicated in cognitive processes by tDCS.
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Affiliation(s)
- Jiheon Kim
- Department of Psychiatry, Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea
- Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
- *These first authors contributed equally to this work
| | - Seungchan Park
- Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
- *These first authors contributed equally to this work
| | - Hansol Kim
- Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Daeyoung Roh
- Department of Psychiatry, Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea
- Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Do Hoon Kim
- Department of Psychiatry, Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea
- Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
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Huo C, Xu G, Xie H, Chen T, Shao G, Wang J, Li W, Wang D, Li Z. Functional near-infrared spectroscopy in non-invasive neuromodulation. Neural Regen Res 2024; 19:1517-1522. [PMID: 38051894 PMCID: PMC10883499 DOI: 10.4103/1673-5374.387970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 08/14/2023] [Indexed: 12/07/2023] Open
Abstract
ABSTRACT Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks, which have been widely applied in the field of central neurological diseases, such as stroke, Parkinson's disease, and mental disorders. Although significant advances have been made in neuromodulation technologies, the identification of optimal neurostimulation parameters including the cortical target, duration, and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits. Moreover, the neural mechanism underlying neuromodulation for improved behavioral performance remains poorly understood. Recently, advancements in neuroimaging have provided insight into neuromodulation techniques. Functional near-infrared spectroscopy, as a novel non-invasive optical brain imaging method, can detect brain activity by measuring cerebral hemodynamics with the advantages of portability, high motion tolerance, and anti-electromagnetic interference. Coupling functional near-infrared spectroscopy with neuromodulation technologies offers an opportunity to monitor the cortical response, provide real-time feedback, and establish a closed-loop strategy integrating evaluation, feedback, and intervention for neurostimulation, which provides a theoretical basis for development of individualized precise neurorehabilitation. We aimed to summarize the advantages of functional near-infrared spectroscopy and provide an overview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation, transcranial electrical stimulation, neurofeedback, and brain-computer interfaces. Furthermore, the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized. In conclusion, functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central neural reorganization to achieve better functional recovery from central nervous system diseases.
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Affiliation(s)
- Congcong Huo
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
| | - Gongcheng Xu
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
| | - Hui Xie
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
| | - Tiandi Chen
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
| | - Guangjian Shao
- School of Mechatronic Engineering and Automation, Foshan University, Foshan, Guangdong Province, China
| | - Jue Wang
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
- Key Laboratory of Neuro-functional Information and Rehabilitation Engineering of the Ministry of Civil Affairs, Beijing, China
| | - Wenhao Li
- School of Rehabilitation Engineering, Beijing College of Social Administration, Beijing, China
| | - Daifa Wang
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Zengyong Li
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
- Key Laboratory of Neuro-functional Information and Rehabilitation Engineering of the Ministry of Civil Affairs, Beijing, China
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Qi S, Liu X, Yu J, Liang Z, Liu Y, Wang X. Temporally interfering electric fields brain stimulation in primary motor cortex of mice promotes motor skill through enhancing neuroplasticity. Brain Stimul 2024; 17:245-257. [PMID: 38428583 DOI: 10.1016/j.brs.2024.02.014] [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: 10/26/2023] [Revised: 02/09/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024] Open
Abstract
Temporal interference (TI) electric field brain stimulation is a novel neuromodulation technique that enables the non-invasive modulation of deep brain regions, but few advances about TI stimulation effectiveness and mechanisms have been reported. Conventional transcranial alternating current stimulation (tACS) can enhance motor skills, whether TI stimulation has an effect on motor skills in mice has not been elucidated. In the present study, TI stimulation was proved to stimulating noninvasively primary motor cortex (M1) of mice, and that TI stimulation with an envelope wave frequency of 20 Hz (Δ f = 20 Hz) once a day for 20 min for 7 consecutive days significantly improved the motor skills of mice. The mechanism of action may be related to regulating of neurotransmitter metabolism, increasing the expression of synapse-related proteins, promoting neurotransmitter release, increasing dendritic spine density, enhancing the number of synaptic vesicles and the thickness of postsynaptic dense material, and ultimately enhance neuronal excitability and plasticity. It is the first report about TI stimulation promoting motor skills of mice and describing its mechanisms.
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Affiliation(s)
- Shuo Qi
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China; School of Exercise and Health, Shanghai University of Sport, Shanghai, China; School of Sport and Health, Shandong Sport University, Jinan, China
| | - Xiaodong Liu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China; School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Jinglun Yu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China; School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Zhiqiang Liang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China; School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Yu Liu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China; School of Exercise and Health, Shanghai University of Sport, Shanghai, China.
| | - Xiaohui Wang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China; School of Exercise and Health, Shanghai University of Sport, Shanghai, China.
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Figeys M, Loucks TM, Leung AWS, Kim ES. Transcranial direct current stimulation over the right dorsolateral prefrontal cortex increases oxyhemoglobin concentration and cognitive performance dependent on cognitive load. Behav Brain Res 2023; 443:114343. [PMID: 36787866 DOI: 10.1016/j.bbr.2023.114343] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/20/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
Transcranial direct current stimulation (tDCS) has been explored as a potential method for cognitive enhancement. tDCS may induce a cascade of neurophysiological changes including alterations in cerebral oxygenation. However, the effects of tDCS on the cognitive-cerebral oxygenation interaction remains unclear. Further, oxygenation variability across individuals remains minimally controlled for. The purpose of this sham-controlled study was to test the effects of anodal tDCS over the right dorsolateral prefrontal cortex (DLPFC) on the interaction between working memory and cerebral oxygenation while controlling for individual oxygenation variability. Thirty-three adults received resting-state functional near-infrared spectroscopy (fNIRS) recordings over bilateral prefrontal cortices. Following this, working memory was tested using a Toulouse n-back task concurrently paired with fNIRS, with measurements taken before and after 20 min of anodal or sham tDCS at 1.5 mA. With individual oxygenation controlled for, anodal tDCS was found to increase the oxyhemoglobin concentration over the right DLPFC during the 2-back (q = .015) and 3-back (q = .008) conditions. Additionally, anodal tDCS was found to improve accuracy during the 3-back task by 13.4 % (p = .028) and decrease latency by 250 ms (p = .013). The increase in oxyhemoglobin was strongly correlated with increases in accuracy (p = .041) and decreases in latency during the 3-back span (p = .017). Taken together, anodal tDCS over the right DLPFC was found to regionally increase oxyhemoglobin concentrations and improve working memory performance in higher cognitive load conditions.
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Affiliation(s)
- Mathieu Figeys
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton T6G 2G4, Alberta, Canada.
| | - Torrey M Loucks
- Department of Communication Sciences and Disorders, School of Applied Health Sciences, Brooks Rehabilitation College of Healthcare Sciences, Jacksonville University - Palm Coast Campus, FL, United States
| | - Ada W S Leung
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton T6G 2G4, Alberta, Canada; Department of Occupational Therapy, University of Alberta, Edmonton T6G 2G4, Alberta, Canada
| | - Esther S Kim
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton T6G 2G4, Alberta, Canada; Department of Communication Sciences and Disorders, University of Alberta, Edmonton T6G 2G4, Alberta, Canada
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Montero-Hernandez S, Pollonini L, Park L, Martorella G, Miao H, Mathis KB, Ahn H. Self-administered transcranial direct current stimulation treatment of knee osteoarthritis alters pain-related fNIRS connectivity networks. NEUROPHOTONICS 2023; 10:015011. [PMID: 37006323 PMCID: PMC10063907 DOI: 10.1117/1.nph.10.1.015011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 03/07/2023] [Indexed: 06/19/2023]
Abstract
Significance Knee osteoarthritis (OA) is a disease that causes chronic pain in the elderly population. Currently, OA is mainly treated pharmacologically with analgesics, although research has shown that neuromodulation via transcranial direct current stimulation (tDCS) may be beneficial in reducing pain in clinical settings. However, no studies have reported the effects of home-based self-administered tDCS on functional brain networks in older adults with knee OA. Aim We used functional near-infrared spectroscopy (fNIRS) to investigate the functional connectivity effects of tDCS on underlying pain processing mechanisms at the central nervous level in older adults with knee OA. Approach Pain-related brain connectivity networks were extracted using fNIRS at baseline and for three consecutive weeks of treatment from 120 subjects randomly assigned to two groups undergoing active tDCS and sham tDCS. Results Our results showed that the tDCS intervention significantly modulated pain-related connectivity correlation only in the group receiving active treatment. We also found that only the active treatment group showed a significantly reduced number and strength of functional connections evoked during nociception in the prefrontal cortex, primary motor (M1), and primary somatosensory (S1) cortices. To our knowledge, this is the first study in which the effect of tDCS on pain-related connectivity networks is investigated using fNIRS. Conclusions fNIRS-based functional connectivity can be effectively used to investigate neural circuits of pain at the cortical level in association with nonpharmacological, self-administered tDCS treatment.
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Affiliation(s)
| | - Luca Pollonini
- University of Houston, Department of Engineering Technology, Houston, Texas, United States
- University of Houston, Department of Electrical and Computer Engineering, Houston, Texas, United States
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- Basque Center on Cognition, Brain and Language, San Sebastian, Spain
| | - Lindsey Park
- Florida State University, College of Nursing, Tallahassee, Florida, United States
| | - Geraldine Martorella
- Florida State University, College of Nursing, Tallahassee, Florida, United States
| | - Hongyu Miao
- Florida State University, College of Nursing, Tallahassee, Florida, United States
| | - Kenneth B. Mathis
- The University of Texas Health Science Center at Houston, McGovern Medical School, Department of Orthopedic Surgery, Houston, Texas, United States
| | - Hyochol Ahn
- Florida State University, College of Nursing, Tallahassee, Florida, United States
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Martin DM, Berryhill ME, Dielenberg V. Can brain stimulation enhance cognition in clinical populations? A critical review. Restor Neurol Neurosci 2022:RNN211230. [PMID: 36404559 DOI: 10.3233/rnn-211230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many psychiatric and neurological conditions are associated with cognitive impairment for which there are very limited treatment options. Brain stimulation methodologies show promise as novel therapeutics and have cognitive effects. Electroconvulsive therapy (ECT), known more for its related transient adverse cognitive effects, can produce significant cognitive improvement in the weeks following acute treatment. Transcranial magnetic stimulation (TMS) is increasingly used as a treatment for major depression and has acute cognitive effects. Emerging research from controlled studies suggests that repeated TMS treatments may additionally have cognitive benefit. ECT and TMS treatment cause neurotrophic changes, although whether these are associated with cognitive effects remains unclear. Transcranial electrical stimulation methods including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) are in development as novel treatments for multiple psychiatric conditions. These treatments may also produce cognitive enhancement particularly when stimulation occurs concurrently with a cognitive task. This review summarizes the current clinical evidence for these brain stimulation treatments as therapeutics for enhancing cognition. Acute, or short-lasting, effects as well as longer-term effects from repeated treatments are reviewed, together with potential putative neural mechanisms. Areas of future research are highlighted to assist with optimization of these approaches for enhancing cognition.
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Affiliation(s)
- Donel M. Martin
- Sydney Neurostimulation Centre, Discipline of Psychiatry and Mental Health UNSW, Black Dog Institute, Sydney, New South Wales, Australia
| | - Marian E. Berryhill
- Memory and Brain Lab, Programs in Cognitive and Brain Sciences, and Integrative Neuroscience, University of Nevada, Reno, NV, USA
| | - Victoria Dielenberg
- Sydney Neurostimulation Centre, Discipline of Psychiatry and Mental Health UNSW, Black Dog Institute, Sydney, New South Wales, Australia
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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: 27] [Impact Index Per Article: 9.0] [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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Figeys M, Villarey S, Leung AWS, Raso J, Buchan S, Kammerer H, Rawani D, Kohls-Wiebe M, Kim ES. tDCS over the left prefrontal Cortex improves mental flexibility and inhibition in geriatric inpatients with symptoms of depression or anxiety: A pilot randomized controlled trial. FRONTIERS IN REHABILITATION SCIENCES 2022; 3:997531. [PMID: 36386776 PMCID: PMC9641275 DOI: 10.3389/fresc.2022.997531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/04/2022] [Indexed: 12/04/2022]
Abstract
BACKGROUND Patients with depression and/or anxiety are commonly seen in inpatient geriatric settings. Both disorders are associated with an increased risk of cognitive impairments, notably in executive functioning. Transcranial direct current stimulation (tDCS), a type of non-invasive brain stimulation, involves the administration of a low-dose electrical current to induce neuromodulation, which ultimately may act on downstream cognitive processing. OBJECTIVE The purpose of this study was to determine the effects of tDCS on executive functioning in geriatric inpatients with symptoms of depression and/or anxiety. DESIGN Pilot Randomized Controlled Trial. SETTING Specialized geriatric wards in a tertiary rehabilitation hospital. METHODS Thirty older-aged adults were recruited, of which twenty completed ten-to-fifteen sessions of 1.5 mA anodal or sham tDCS over the left dorsolateral prefrontal cortex. Cognitive assessments were administered at baseline and following the tDCS protocol; analyses examined the effects of tDCS on cognitive performance between groups (anodal or sham tDCS). RESULTS tDCS was found to increase inhibitory processing and cognitive flexibility in the anodal tDCS group, with significant changes on the Stroop test and Trail Making Test-Part B. No significant changes were observed on measures of attention or working memory. DISCUSSION These results provide preliminary evidence that tDCS-induced neuromodulation may selectively improve cognitive processing in older adults with symptoms of depression and/or anxiety. CLINICAL TRIALS REGISTRATION www.clinicaltrials.gov, NCT04558177.
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Affiliation(s)
- Mathieu Figeys
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada,Alberta Health Services, Edmonton, AB, Canada,Correspondence: Mathieu Figeys
| | - Sheryn Villarey
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Ada W. S. Leung
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada,Department of Occupational Therapy, University of Alberta, Edmonton, AB, Canada
| | - Jim Raso
- Alberta Health Services, Edmonton, AB, Canada
| | - Steven Buchan
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | | | - David Rawani
- Alberta Health Services, Edmonton, AB, Canada,Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | | | - Esther S. Kim
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada,Department of Communication Sciences and Disorders, University of Alberta, Edmonton, AB, Canada
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Assecondi S, Hu R, Kroeker J, Eskes G, Shapiro K. Older adults with lower working memory capacity benefit from transcranial direct current stimulation when combined with working memory training: A preliminary study. Front Aging Neurosci 2022; 14:1009262. [PMID: 36299611 PMCID: PMC9589058 DOI: 10.3389/fnagi.2022.1009262] [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: 08/01/2022] [Accepted: 09/20/2022] [Indexed: 11/27/2022] Open
Abstract
Aging is a very diverse process: successful agers retain most cognitive functioning, while others experience mild to severe cognitive decline. This decline may eventually negatively impact one’s everyday activities. Therefore, scientists must develop approaches to counteract or, at least, slow down the negative change in cognitive performance of aging individuals. Combining cognitive training and transcranial direct current stimulation (tDCS) is a promising approach that capitalizes on the plasticity of brain networks. However, the efficacy of combined methods depends on individual characteristics, such as the cognitive and emotional state of the individual entering the training program. In this report, we explored the effectiveness of working memory training, combined with tDCS to the right dorsolateral prefrontal cortex (DLPFC), to manipulate working memory performance in older individuals. We hypothesized that individuals with lower working memory capacity would benefit the most from the combined regimen. Thirty older adults took part in a 5-day combined regimen. Before and after the training, we evaluated participants’ working memory performance with five working memory tasks. We found that individual characteristics influenced the outcome of combined cognitive training and tDCS regimens, with the intervention selectively benefiting old-old adults with lower working memory capacity. Future work should consider developing individualized treatments by considering individual differences in cognitive profiles.
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Affiliation(s)
- Sara Assecondi
- Center for Mind/Brain Sciences—CIMeC, University of Trento, Rovereto, Italy
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, United Kingdom
- *Correspondence: Sara Assecondi, ,
| | - Rong Hu
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Department of Neurology, School of Medicine, Guangzhou First People’s Hospital, South China University of Technology, Guangzhou, China
| | - Jacob Kroeker
- Departments of Psychiatry and Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Gail Eskes
- Departments of Psychiatry and Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Kim Shapiro
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, United Kingdom
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12
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Sansevere KS, Wooten T, McWilliams T, Peach S, Hussey EK, Brunyé TT, Ward N. Self-reported Outcome Expectations of Non-invasive Brain Stimulation Are Malleable: a Registered Report that Replicates and Extends Rabipour et al. (2017). JOURNAL OF COGNITIVE ENHANCEMENT 2022. [DOI: 10.1007/s41465-022-00250-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Smits FM, Geuze E, de Kort GJ, Kouwer K, Geerlings L, van Honk J, Schutter DJ. Effects of Multisession Transcranial Direct Current Stimulation on Stress Regulation and Emotional Working Memory: A Randomized Controlled Trial in Healthy Military Personnel. Neuromodulation 2022:S1094-7159(22)00721-8. [DOI: 10.1016/j.neurom.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 05/02/2022] [Accepted: 05/02/2022] [Indexed: 10/16/2022]
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14
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Hong KS, Khan MNA, Ghafoor U. Non-invasive transcranial electrical brain stimulation guided by functional near-infrared spectroscopy for targeted neuromodulation: A review. J Neural Eng 2022; 19. [PMID: 35905708 DOI: 10.1088/1741-2552/ac857d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/29/2022] [Indexed: 11/12/2022]
Abstract
One of the primary goals in cognitive neuroscience is to understand the neural mechanisms on which cognition is based. Researchers are trying to find how cognitive mechanisms are related to oscillations generated due to brain activity. The research focused on this topic has been considerably aided by developing non-invasive brain stimulation techniques. The dynamics of brain networks and the resultant behavior can be affected by non-invasive brain stimulation techniques, which make their use a focus of interest in many experiments and clinical fields. One essential non-invasive brain stimulation technique is transcranial electrical stimulation (tES), subdivided into transcranial direct and alternating current stimulation. tES has recently become more well-known because of the effective results achieved in treating chronic conditions. In addition, there has been exceptional progress in the interpretation and feasibility of tES techniques. Summarizing the beneficial effects of tES, this article provides an updated depiction of what has been accomplished to date, brief history, and the open questions that need to be addressed in the future. An essential issue in the field of tES is stimulation duration. This review briefly covers the stimulation durations that have been utilized in the field while monitoring the brain using functional-near infrared spectroscopy-based brain imaging.
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Affiliation(s)
- Keum-Shik Hong
- Department of Cogno-mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumgeong-gu, Busan, Busan, 609735, Korea (the Republic of)
| | - M N Afzal Khan
- Pusan National University, Department of Mechanical Engineering, Busan, 46241, Korea (the Republic of)
| | - Usman Ghafoor
- School of Mechanical Engineering, Pusan National University College of Engineering, room 204, Busan, 46241, Korea (the Republic of)
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15
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Au J, Smith-Peirce RN, Carbone E, Moon A, Evans M, Jonides J, Jaeggi SM. Effects of Multisession Prefrontal Transcranial Direct Current Stimulation on Long-term Memory and Working Memory in Older Adults. J Cogn Neurosci 2022; 34:1015-1037. [PMID: 35195728 PMCID: PMC9836784 DOI: 10.1162/jocn_a_01839] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Transcranial direct current stimulation (tDCS) is a noninvasive form of electrical brain stimulation popularly used to augment the effects of working memory (WM) training. Although success has been mixed, some studies report enhancements in WM performance persisting days, weeks, or even months that are actually more reminiscent of consolidation effects typically observed in the long-term memory (LTM) domain, rather than WM improvements per se. Although tDCS has been often reported to enhance both WM and LTM, these effects have never been directly compared within the same study. However, given their considerable neural and behavioral overlap, this is a timely comparison to make. This study reports results from a multisession intervention in older adults comparing active and sham tDCS over the left dorsolateral pFC during training on both an n-back WM task and a word learning LTM task. We found strong and robust effects on LTM, but mixed effects on WM that only emerged for those with lower baseline ability. Importantly, mediation analyses showed an indirect effect of tDCS on WM that was mediated by improvements in consolidation. We conclude that tDCS over the left dorsolateral pFC can be used as an effective intervention to foster long-term learning and memory consolidation in aging, which can manifest in performance improvements across multiple memory domains.
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Affiliation(s)
- Jacky Au
- School of Education, University of California, Irvine, Irvine CA, 92697, USA
| | | | - Elena Carbone
- Department of General Psychology, University of Padova, Padova, 35131, Italy
| | - Austin Moon
- Department of Psychology, University of California, Riverside, Riverside CA, 92521, USA
| | - Michelle Evans
- Department of Psychology, University of Michigan, Ann Arbor MI, 48109, USA
| | - John Jonides
- Department of Psychology, University of Michigan, Ann Arbor MI, 48109, USA
| | - Susanne M. Jaeggi
- School of Education, University of California, Irvine, Irvine CA, 92697, USA
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16
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Assecondi S, Villa-Sánchez B, Shapiro K. Event-Related Potentials as Markers of Efficacy for Combined Working Memory Training and Transcranial Direct Current Stimulation Regimens: A Proof-of-Concept Study. Front Syst Neurosci 2022; 16:837979. [PMID: 35547238 PMCID: PMC9083230 DOI: 10.3389/fnsys.2022.837979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/28/2022] [Indexed: 11/14/2022] Open
Abstract
Our brains are often under pressure to process a continuous flow of information in a short time, therefore facing a constantly increasing demand for cognitive resources. Recent studies have highlighted that a lasting improvement of cognitive functions may be achieved by exploiting plasticity, i.e., the brain’s ability to adapt to the ever-changing cognitive demands imposed by the environment. Transcranial direct current stimulation (tDCS), when combined with cognitive training, can promote plasticity, amplify training gains and their maintenance over time. The availability of low-cost wearable devices has made these approaches more feasible, albeit the effectiveness of combined training regimens is still unclear. To quantify the effectiveness of such protocols, many researchers have focused on behavioral measures such as accuracy or reaction time. These variables only return a global, non-specific picture of the underlying cognitive process. Electrophysiology instead has the finer grained resolution required to shed new light on the time course of the events underpinning processes critical to cognitive control, and if and how these processes are modulated by concurrent tDCS. To the best of our knowledge, research in this direction is still very limited. We investigate the electrophysiological correlates of combined 3-day working memory training and non-invasive brain stimulation in young adults. We focus on event-related potentials (ERPs), instead of other features such as oscillations or connectivity, because components can be measured on as little as one electrode. ERP components are, therefore, well suited for use with home devices, usually equipped with a limited number of recording channels. We consider short-, mid-, and long-latency components typically elicited by working memory tasks and assess if and how the amplitude of these components are modulated by the combined training regimen. We found no significant effects of tDCS either behaviorally or in brain activity, as measured by ERPs. We concluded that either tDCS was ineffective (because of the specific protocol or the sample under consideration, i.e., young adults) or brain-related changes, if present, were too subtle. Therefore, we suggest that other measures of brain activity may be more appropriate/sensitive to training- and/or tDCS-induced modulations, such as network connectivity, especially in young adults.
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Affiliation(s)
- Sara Assecondi
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
- *Correspondence: Sara Assecondi, ,
| | | | - Kim Shapiro
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, United Kingdom
- Center for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
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17
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Johnson EL, Arciniega H, Jones KT, Kilgore-Gomez A, Berryhill ME. Individual predictors and electrophysiological signatures of working memory enhancement in aging. Neuroimage 2022; 250:118939. [PMID: 35104647 PMCID: PMC8923157 DOI: 10.1016/j.neuroimage.2022.118939] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 01/25/2022] [Indexed: 12/21/2022] Open
Abstract
A primary goal of translational neuroscience is to identify the neural mechanisms of age-related cognitive decline and develop protocols to maximally improve cognition. Here, we demonstrate how interventions that apply noninvasive neurostimulation to older adults improve working memory (WM). We found that one session of sham-controlled transcranial direct current stimulation (tDCS) selectively improved WM in older adults with more education, extending earlier work and underscoring the importance of identifying individual predictors of tDCS responsivity. Improvements in WM were associated with two distinct electrophysiological signatures. First, a broad enhancement of theta network synchrony tracked improvements in behavioral accuracy, with tDCS effects moderated by education level. Further analysis revealed that accuracy dynamics reflected an anterior-posterior network distribution regardless of cathode placement. Second, specific enhancements of theta-gamma phase-amplitude coupling (PAC) reflecting tDCS current flow tracked improvements in reaction time (RT). RT dynamics further explained inter-individual variability in WM improvement independent of education. These findings illuminate theta network synchrony and theta-gamma PAC as distinct but complementary mechanisms supporting WM in aging. Both mechanisms are amenable to intervention, the effectiveness of which can be predicted by individual demographic factors.
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Affiliation(s)
- Elizabeth L Johnson
- Departments of Medical Social Sciences and Pediatrics, Northwestern University, Chicago, IL, 60611, United States.
| | - Hector Arciniega
- Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02215, United States
| | - Kevin T Jones
- Department of Neurology, Neuroscape, University of California-San Francisco, San Francisco, CA, 94158, United States
| | - Alexandrea Kilgore-Gomez
- Department of Psychology, Program in Cognitive and Brain Sciences, Program in Integrative Neuroscience, University of Nevada, Reno, 89557, United States
| | - Marian E Berryhill
- Department of Psychology, Program in Cognitive and Brain Sciences, Program in Integrative Neuroscience, University of Nevada, Reno, 89557, United States.
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18
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Yaqub MA, Hong KS, Zafar A, Kim CS. Control of Transcranial Direct Current Stimulation Duration by Assessing Functional Connectivity of Near-Infrared Spectroscopy Signals. Int J Neural Syst 2021; 32:2150050. [PMID: 34609264 DOI: 10.1142/s0129065721500507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Transcranial direct current stimulation (tDCS) has been shown to create neuroplasticity in healthy and diseased populations. The control of stimulation duration by providing real-time brain state feedback using neuroimaging is a topic of great interest. This study presents the feasibility of a closed-loop modulation for the targeted functional network in the prefrontal cortex. We hypothesize that we cannot improve the brain state further after reaching a specific state during a stimulation therapy session. A high-definition tDCS of 1[Formula: see text]mA arranged in a ring configuration was applied at the targeted right prefrontal cortex of 15 healthy male subjects for 10[Formula: see text]min. Functional near-infrared spectroscopy was used to monitor hemoglobin chromophores during the stimulation period continuously. The correlation matrices obtained from filtered oxyhemoglobin were binarized to form subnetworks of short- and long-range connections. The connectivity in all subnetworks was analyzed individually using a new quantification measure of connectivity percentage based on the correlation matrix. The short-range network in the stimulated hemisphere showed increased connectivity in the initial stimulation phase. However, the increase in connection density reduced significantly after 6[Formula: see text]min of stimulation. The short-range network of the left hemisphere and the long-range network gradually increased throughout the stimulation period. The connectivity percentage measure showed a similar response with network theory parameters. The connectivity percentage and network theory metrics represent the brain state during the stimulation therapy. The results from the network theory metrics, including degree centrality, efficiency, and connection density, support our hypothesis and provide a guideline for feedback on the brain state. The proposed neuro-feedback scheme is feasible to control the stimulation duration to avoid overdosage.
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Affiliation(s)
- M Atif Yaqub
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Keum-Shik Hong
- School of Mechanical Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea
| | - Amad Zafar
- Department of Electrical Engineering, University of Lahore, Sihala Zone V, Islamabad, Pakistan
| | - Chang-Seok Kim
- Department of Cogno-Mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea
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19
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Anodal tDCS augments and preserves working memory beyond time-on-task deficits. Sci Rep 2021; 11:19134. [PMID: 34580390 PMCID: PMC8476579 DOI: 10.1038/s41598-021-98636-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/30/2021] [Indexed: 12/04/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (DLPFC) has been shown to promote working memory (WM), however, its efficacy against time-on-task-related performance decline and associated cognitive fatigue remains uncertain. This study examined the impact of anodal tDCS of the left DLPFC on performance during a fatiguing visuospatial WM test. We adopted a repeated measures design, where 32 healthy adults (16 female), underwent anodal, control and sham tDCS on separate days. They completed an hour long two-back test, with stimulation intensity, onset, and duration set at 1 mA, at the 20th minute for 10 minutes respectively. Task performance, subjective responses, and heart rate variability (HRV) were captured during the experiment. Anodal tDCS substantially improved WM relative to sham tDCS and control in both sexes. These benefits lasted beyond the stimulation interval, and were unique across performance measures. However, no perceptual changes in subjective effort or fatigue levels were noted between conditions, although participants reported greater discomfort during stimulation. While mood and sleepiness changed with time-on-task, reflecting fatigue, these were largely similar across conditions. HRV increased under anodal tDCS and control, and plateaued under sham tDCS. We found that short duration anodal tDCS at 1 mA was an effective countermeasure to time-on-task deficits during a visuospatial two-back task, with enhancement and preservation of WM capacity. However, these improvements were not available at a perceptual level. Therefore, wider investigations are necessary to determine “how” such solutions will be operationalized in the field, especially within human-centered systems.
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20
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Zanto TP, Jones KT, Ostrand AE, Hsu WY, Campusano R, Gazzaley A. Individual differences in neuroanatomy and neurophysiology predict effects of transcranial alternating current stimulation. Brain Stimul 2021; 14:1317-1329. [PMID: 34481095 DOI: 10.1016/j.brs.2021.08.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 08/11/2021] [Accepted: 08/19/2021] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND Noninvasive transcranial electrical stimulation (tES) research has been plagued with inconsistent effects. Recent work has suggested neuroanatomical and neurophysiological variability may alter tES efficacy. However, direct evidence is limited. OBJECTIVE We have previously replicated effects of transcranial alternating current stimulation (tACS) on improving multitasking ability in young adults. Here, we attempt to assess whether these stimulation parameters have comparable effects in older adults (aged 60-80 years), which is a population known to have greater variability in neuroanatomy and neurophysiology. It is hypothesized that this variability in neuroanatomy and neurophysiology will be predictive of tACS efficacy. METHODS We conducted a pre-registered study where tACS was applied above the prefrontal cortex (between electrodes F3-F4) while participants were engaged in multitasking. Participants were randomized to receive either 6-Hz (theta) tACS for 26.67 min daily for three days (80 min total; Long Exposure Theta group), 6-Hz tACS for 5.33 min daily (16-min total; Short Exposure Theta group), or 1-Hz tACS for 26.67 min (80 min total; Control group). To account for neuroanatomy, magnetic resonance imaging data was used to form individualized models of the tACS-induced electric field (EF) within the brain. To account for neurophysiology, electroencephalography data was used to identify individual peak theta frequency. RESULTS Results indicated that only in the Long Theta group, performance change was correlated with modeled EF and peak theta frequency. Together, modeled EF and peak theta frequency accounted for 54%-65% of the variance in tACS-related performance improvements, which sustained for a month. CONCLUSION These results demonstrate the importance of individual differences in neuroanatomy and neurophysiology in tACS research and help account for inconsistent effects across studies.
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Affiliation(s)
- Theodore P Zanto
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA; Neuroscape, University of California-San Francisco, San Francisco, CA, USA.
| | - Kevin T Jones
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA; Neuroscape, University of California-San Francisco, San Francisco, CA, USA
| | - Avery E Ostrand
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA; Neuroscape, University of California-San Francisco, San Francisco, CA, USA
| | - Wan-Yu Hsu
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA
| | - Richard Campusano
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA; Neuroscape, University of California-San Francisco, San Francisco, CA, USA
| | - Adam Gazzaley
- Department of Neurology, University of California-San Francisco, San Francisco, CA, USA; Neuroscape, University of California-San Francisco, San Francisco, CA, USA; Departments of Physiology and Psychiatry, University of California-San Francisco, San Francisco, CA, USA
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21
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Wischnewski M, Mantell KE, Opitz A. Identifying regions in prefrontal cortex related to working memory improvement: A novel meta-analytic method using electric field modeling. Neurosci Biobehav Rev 2021; 130:147-161. [PMID: 34418436 DOI: 10.1016/j.neubiorev.2021.08.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 07/09/2021] [Accepted: 08/15/2021] [Indexed: 12/17/2022]
Abstract
Altering cortical activity using transcranial direct current stimulation (tDCS) has been shown to improve working memory (WM) performance. Due to large inter-experimental variability in the tDCS montage configuration and strength of induced electric fields, results have been mixed. Here, we present a novel meta-analytic method relating behavioral effect sizes to electric field strength to identify brain regions underlying largest tDCS-induced WM improvement. Simulations on 69 studies targeting left prefrontal cortex showed that tDCS electric field strength in lower dorsolateral prefrontal cortex (Brodmann area 45/47) relates most strongly to improved WM performance. This region explained 7.8 % of variance, equaling a medium effect. A similar region was identified when correlating WM performance and electric field strength of right prefrontal tDCS studies (n = 18). Maximum electric field strength of five previously used tDCS configurations were outside of this location. We thus propose a new tDCS montage which maximizes the tDCS electric field strength in that brain region. Our findings can benefit future tDCS studies that aim to affect WM function.
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Affiliation(s)
- Miles Wischnewski
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States.
| | - Kathleen E Mantell
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Alexander Opitz
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States
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22
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Figeys M, Zeeman M, Kim ES. Effects of Transcranial Direct Current Stimulation (tDCS) on Cognitive Performance and Cerebral Oxygen Hemodynamics: A Systematic Review. Front Hum Neurosci 2021; 15:623315. [PMID: 33897392 PMCID: PMC8058208 DOI: 10.3389/fnhum.2021.623315] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/11/2021] [Indexed: 11/24/2022] Open
Abstract
Background: There is increasing evidence to support the efficacy of transcranial direct current stimulation (tDCS) applications in cognitive augmentation and rehabilitation. Neuromodulation achieved with tDCS may further regulate regional cerebral perfusion affiliated through the neurovascular unit; however, components of cerebral perfusion decrease across aging. A novel neuroimaging approach, functional near-infrared spectroscopy (fNIRS), can aid in quantifying these regional perfusional changes. To date, the interaction of the effects of tDCS on cognitive performance across the lifespan and obtained fNIRS hemodynamic responses remain unknown. Objective: This review aims to examine the effects of tDCS on cognitive performance and fNIRS hemodynamic responses within the context of cognitive aging. Methods: Six databases were searched for studies. Quality appraisal and data extraction were conducted by two independent reviewers. Meta-analysis was carried out to determine overall and subgroup effect sizes. Results: Eight studies met inclusion criteria. The overall effect size demonstrates that tDCS can alter cognitive performance and fNIRS signals, with aging being a potential intermediary in tDCS efficacy. Conclusion: From the studies included, the effects of tDCS on cognitive performance and fNIRS metrics are most prominent in young healthy adults and appear to become less robust with increasing age. Given the small number of studies included in this review further investigation is recommended.
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Affiliation(s)
- Mathieu Figeys
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michael Zeeman
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Esther Sung Kim
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada.,Department of Communication Sciences and Disorders, University of Alberta, Edmonton, AB, Canada
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23
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The impact of transcranial Direct Current stimulation on rumination: A systematic review of the sham-controlled studies in healthy and clinical samples. Compr Psychiatry 2021; 106:152226. [PMID: 33581448 DOI: 10.1016/j.comppsych.2021.152226] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/16/2020] [Accepted: 12/20/2020] [Indexed: 01/27/2023] Open
Abstract
INTRODUCTION Broadly considered a transdiagnostic feature of psychological disorders, rumination is associated with lower treatment response, slower recovery rates, and higher relapse rates. Accordingly, research has focused on the development of interventions to alleviate rumination. Recently, transcranial Direct Current Stimulation (tDCS) has emerged as a promising tool to do so. METHODS We performed a systematic review of sham-controlled tDCS studies targeting rumination among healthy participants or patients with psychiatric disorders, investigating the effectiveness of tDCS in reducing rumination, and assessing the research quality of this nascent field. RESULTS We identified nine studies, with five reporting a significant impact of tDCS on rumination. We also outlined a few tDCS parameters (e.g., stimulation duration, electrode size) and research methods' features (e.g., within- versus between-research designs) characterizing those positive-finding studies. However, these studies were characterized by substantial heterogeneity (e.g., methodological flaws, lack of open science practices), precluding any definite statement about the best way to target rumination via tDCS. Moreover, several strong methodological limitations were also present across those studies. DISCUSSION Although our systematic review identifies the strengths and weaknesses of the available research about the impact of tDCS on rumination, it calls for strong efforts to improve this nascent field's current methodological caveats. We discuss how open science practices can help to usher this field forward.
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24
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Assecondi S, Hu R, Eskes G, Pan X, Zhou J, Shapiro K. Impact of tDCS on working memory training is enhanced by strategy instructions in individuals with low working memory capacity. Sci Rep 2021; 11:5531. [PMID: 33750803 PMCID: PMC7943602 DOI: 10.1038/s41598-021-84298-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 02/09/2021] [Indexed: 11/09/2022] Open
Abstract
Interventions to improve working memory, e.g. by combining task rehearsal and non-invasive brain stimulation, are gaining popularity. Many factors, however, affect the outcome of these interventions. We hypothesize that working memory capacity at baseline predicts how an individual performs on a working memory task, by setting limits on the benefit derived from tDCS when combined with strategy instructions; specifically, we hypothesize that individuals with low capacity will benefit the most. Eighty-four participants underwent two sessions of an adaptive working memory task (n-back) on two consecutive days. Participants were split into four independent groups (SHAM vs ACTIVE stimulation and STRATEGY vs no STRATEGY instructions). For the purpose of analysis, individuals were divided based on their baseline working memory capacity. Results support our prediction that the combination of tDCS and strategy instructions is particularly beneficial in low capacity individuals. Our findings contribute to a better understanding of factors affecting the outcome of tDCS when used in conjunction with cognitive training to improve working memory. Moreover, our results have implications for training regimens, e.g., by designing interventions predicated on baseline cognitive abilities, or focusing on strategy development for specific attentional skills.
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Affiliation(s)
- Sara Assecondi
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, UK. .,Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, UK.
| | - Rong Hu
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, UK.,Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, UK.,Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
| | - Gail Eskes
- Departments of Psychiatry and Psychology & Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Xiaoping Pan
- Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
| | - Jin Zhou
- Department of Neurology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
| | - Kim Shapiro
- Visual Experience Laboratory, School of Psychology, University of Birmingham, Birmingham, UK.,Center for Human Brain Health (CHBH), University of Birmingham, Birmingham, UK
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Brambilla M, Dinkelbach L, Bigler A, Williams J, Zokaei N, Cohen Kadosh R, Brem AK. The Effect of Transcranial Random Noise Stimulation on Cognitive Training Outcome in Healthy Aging. Front Neurol 2021; 12:625359. [PMID: 33767658 PMCID: PMC7985554 DOI: 10.3389/fneur.2021.625359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/09/2021] [Indexed: 12/20/2022] Open
Abstract
Background and Objective: Aging is associated with a decline in attentional and executive abilities, which are linked to physiological, structural, and functional brain changes. A variety of novel non-invasive brain stimulation methods have been probed in terms of their neuroenhancement efficacy in the last decade; one that holds significant promise is transcranial random noise stimulation (tRNS) that delivers an alternate current at random amplitude and frequency. The aim of this study was to investigate whether repeated sessions of tRNS applied as an add-on to cognitive training (CT) may induce long-term near and far transfer cognitive improvements. Methods: In this sham-controlled, randomized, double-blinded study forty-two older adults (age range 60-86 years) were randomly assigned to one of three intervention groups that received 20 min of 0.705 mA tRNS (N = 14), 1 mA tRNS (N = 14), or sham tRNS (N = 19) combined with 30 min of CT of executive functions (cognitive flexibility, inhibitory control, working memory). tRNS was applied bilaterally over the dorsolateral prefrontal cortices for five sessions. The primary outcome (non-verbal logical reasoning) and other cognitive functions (attention, memory, executive functions) were assessed before and after the intervention and at a 1-month follow-up. Results: Non-verbal logical reasoning, inhibitory control and reaction time improved significantly over time, but stimulation did not differentially affect this improvement. These changes occurred during CT, while no further improvement was observed during follow-up. Performance change in logical reasoning was significantly correlated with age in the group receiving 1 mA tRNS, indicating that older participants profited more from tRNS than younger participants. Performance change in non-verbal working memory was significantly correlated with age in the group receiving sham tRNS, indicating that in contrast to active tRNS, older participants in the sham group declined more than younger participants. Interpretation: CT induced cognitive improvements in all treatment groups, but tRNS did not modulate most of these cognitive improvements. However, the effect of tRNS depended on age in some cognitive functions. We discuss possible explanations leading to this result that can help to improve the design of future neuroenhancement studies in older populations.
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Affiliation(s)
- Michela Brambilla
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
- Biomedical and Clinical Sciences Department, Center for Research and Treatment on Cognitive Dysfunctions, “Luigi Sacco” Hospital, University of Milan, Milan, Italy
| | - Lars Dinkelbach
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
- Department of Neurology, Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University, Duesseldorf, Germany
| | - Annelien Bigler
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Joseph Williams
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
- Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Nahid Zokaei
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Roi Cohen Kadosh
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Anna-Katharine Brem
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
- Department of Neurology, Berenson-Allen Center for Noninvasive Brain Stimulation and Division for Cognitive Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
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Schommartz I, Dix A, Passow S, Li SC. Functional Effects of Bilateral Dorsolateral Prefrontal Cortex Modulation During Sequential Decision-Making: A Functional Near-Infrared Spectroscopy Study With Offline Transcranial Direct Current Stimulation. Front Hum Neurosci 2021; 14:605190. [PMID: 33613203 PMCID: PMC7886709 DOI: 10.3389/fnhum.2020.605190] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
The ability to learn sequential contingencies of actions for predicting future outcomes is indispensable for flexible behavior in many daily decision-making contexts. It remains open whether such ability may be enhanced by transcranial direct current stimulation (tDCS). The present study combined tDCS with functional near-infrared spectroscopy (fNIRS) to investigate potential tDCS-induced effects on sequential decision-making and the neural mechanisms underlying such modulations. Offline tDCS and sham stimulation were applied over the left and right dorsolateral prefrontal cortex (dlPFC) in young male adults (N = 29, mean age = 23.4 years, SD = 3.2) in a double-blind between-subject design using a three-state Markov decision task. The results showed (i) an enhanced dlPFC hemodynamic response during the acquisition of sequential state transitions that is consistent with the findings from a previous functional magnetic resonance imaging (fMRI) study; (ii) a tDCS-induced increase of the hemodynamic response in the dlPFC, but without accompanying performance-enhancing effects at the behavioral level; and (iii) a greater tDCS-induced upregulation of hemodynamic responses in the delayed reward condition that seems to be associated with faster decision speed. Taken together, these findings provide empirical evidence for fNIRS as a suitable method for investigating hemodynamic correlates of sequential decision-making as well as functional brain correlates underlying tDCS-induced modulation. Future research with larger sample sizes for carrying out subgroup analysis is necessary in order to decipher interindividual differences in tDCS-induced effects on sequential decision-making process at the behavioral and brain levels.
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Affiliation(s)
- Iryna Schommartz
- Chair of Lifespan Developmental Neuroscience, Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
- Department of Developmental Psychology, Institute of Psychology, Goethe University Frankfurt, Frankfurt, Germany
| | - Annika Dix
- Chair of Lifespan Developmental Neuroscience, Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
- Centre for Tactile Internet With Human-in-the-Loop, Technische Universität Dresden, Dresden, Germany
| | - Susanne Passow
- Chair of Lifespan Developmental Neuroscience, Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
| | - Shu-Chen Li
- Chair of Lifespan Developmental Neuroscience, Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
- Centre for Tactile Internet With Human-in-the-Loop, Technische Universität Dresden, Dresden, Germany
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Breitling-Ziegler C, Zaehle T, Wellnhofer C, Dannhauer M, Tegelbeckers J, Baumann V, Flechtner HH, Krauel K. Effects of a five-day HD-tDCS application to the right IFG depend on current intensity: A study in children and adolescents with ADHD. PROGRESS IN BRAIN RESEARCH 2021; 264:117-150. [PMID: 34167653 DOI: 10.1016/bs.pbr.2021.01.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Impaired executive functions in ADHD are associated with hypoactivity of the right inferior frontal gyrus (IFG). This region was targeted via repetitive applications of anodal, high-definition transcranial direct current simulation (HD-tDCS) on five consecutive days in 33 ADHD patients (10-17years) and in a healthy control group (n=13, only sham). Patients received either sham (n=13) or verum tDCS with 0.5mA (n=9) or 0.25mA (n=11) depending on individual cutaneous sensitivity. During stimulation, participants performed a combined working memory and response inhibition paradigm (n-back/nogo). At baseline, post, and a 4-month follow up, electroencephalography was recorded during this task. Moreover, interference control (flanker task) and spatial working memory (spanboard task) were assessed to explore possible transfer effects. Omission errors and reaction time variability in all tasks served as measures of attention. In the 0.25mA group increased nogo commission errors indicated a detrimental tDCS effect on response inhibition. After the 5-day stimulation, attentional improvements in the 0.5mA group were indicated by reduced omission errors and reaction time variability. Variability improvements were still evident at follow up. In all groups, nogo P3 amplitudes were reduced post-stimulation, but in the 0.5mA group this reduction was smaller than in the 0.25mA group. Results of the current study suggest distinct effects of tDCS with different current intensities demonstrating the importance of a deeper understanding on the impact of stimulation parameters and repeated tDCS applications to develop effective tDCS-based therapy approaches in ADHD.
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Affiliation(s)
- Carolin Breitling-Ziegler
- Department of Child and Adolescent Psychiatry and Psychotherapy, Otto von Guericke University, Magdeburg, Germany.
| | - Tino Zaehle
- Department of Neurology, Otto von Guericke University, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
| | - Christian Wellnhofer
- Department of Child and Adolescent Psychiatry and Psychotherapy, Otto von Guericke University, Magdeburg, Germany
| | - Moritz Dannhauer
- Scientific Computing and Imaging Institute, Center for Integrated Biomedical Computing, University of Utah, Salt Lake City, UT, United States
| | - Jana Tegelbeckers
- Department of Child and Adolescent Psychiatry and Psychotherapy, Otto von Guericke University, Magdeburg, Germany; Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Valentin Baumann
- Department of Child and Adolescent Psychiatry and Psychotherapy, Otto von Guericke University, Magdeburg, Germany
| | - Hans-Henning Flechtner
- Department of Child and Adolescent Psychiatry and Psychotherapy, Otto von Guericke University, Magdeburg, Germany
| | - Kerstin Krauel
- Department of Child and Adolescent Psychiatry and Psychotherapy, Otto von Guericke University, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
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Cerreta AGB, Mruczek REB, Berryhill ME. Predicting Working Memory Training Benefits From Transcranial Direct Current Stimulation Using Resting-State fMRI. Front Psychol 2020; 11:570030. [PMID: 33154728 PMCID: PMC7591503 DOI: 10.3389/fpsyg.2020.570030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/09/2020] [Indexed: 12/14/2022] Open
Abstract
The effects of transcranial direct current stimulation (tDCS) on working memory (WM) performance are promising but variable and contested. In particular, designs involving one session of tDCS are prone to variable outcomes with notable effects of individual differences. Some participants benefit, whereas others are impaired by the same tDCS protocol. In contrast, protocols including multiple sessions of tDCS more consistently report WM improvement across participants. The objective of the current project was to test whether differences in resting-state connectivity between stimulation site and two WM-relevant networks [default mode network (DMN) and central executive network (CEN)] could account for initial and longitudinal responses to tDCS. Healthy young adults completed 5 days of visual WM training during sham or anodal right frontal tDCS. The behavioral data showed that only the active tDCS group significantly improved over the visual WM training period. There were no significant correlations between initial response to tDCS and resting-state activity. DMN activity in the anterior cingulate cortex significantly correlated with WM training slope. These data underscore the importance of sampling in studies applying tDCS; homogeneity (e.g., of gender, special population, and WM capacity) may produce more consistent data in a single experiment with limited power, whereas heterogeneity is important in determining the mechanism(s) and potential for tDCS-linked protocols. This issue is a limitation in tDCS findings that continues to hamper its optimization and translational value.
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Affiliation(s)
- Adelle G B Cerreta
- Program in Cognitive and Brain Sciences, Program in Integrative Neuroscience, Department of Psychology, University of Nevada, Reno, NV, United States
| | - Ryan E B Mruczek
- Department of Psychology, College of the Holy Cross, Worcester, MA, United States
| | - Marian E Berryhill
- Program in Cognitive and Brain Sciences, Program in Integrative Neuroscience, Department of Psychology, University of Nevada, Reno, NV, United States
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Pellegrini M, Zoghi M, Jaberzadeh S. Can genetic polymorphisms predict response variability to anodal transcranial direct current stimulation of the primary motor cortex? Eur J Neurosci 2020; 53:1569-1591. [PMID: 33048398 DOI: 10.1111/ejn.15002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 09/17/2020] [Accepted: 10/02/2020] [Indexed: 11/28/2022]
Abstract
Genetic mediation of cortical plasticity and the role genetic variants play in previously observed response variability to transcranial direct current stimulation (tDCS) have become important issues in the tDCS literature in recent years. This study investigated whether inter-individual variability to tDCS was in-part genetically mediated. In 61 healthy males, anodal-tDCS (a-tDCS) and sham-tDCS were administered to the primary motor cortex at 1 mA for 10-min via 6 × 4 cm active and 7 × 5 cm return electrodes. Twenty-five single-pulse transcranial magnetic stimulation (TMS) motor evoked potentials (MEP) were recorded to represent corticospinal excitability (CSE). Twenty-five paired-pulse MEPs were recorded with 3 ms inter-stimulus interval (ISI) to assess intracortical inhibition (ICI) via short-interval intracranial inhibition (SICI) and 10 ms ISI for intracortical facilitation (ICF). Saliva samples were tested for specific genetic polymorphisms in genes encoding for excitatory and inhibitory neuroreceptors. Individuals were sub-grouped based on a pre-determined threshold and via statistical cluster analysis. Two distinct subgroups were identified, increases in CSE following a-tDCS (i.e. Responders) and no increase or even reductions in CSE (i.e. Non-responders). No changes in ICI or ICF were reported. No relationships were reported between genetic polymorphisms in excitatory receptor genes and a-tDCS responders. An association was reported between a-tDCS responders and GABRA3 gene polymorphisms encoding for GABA-A receptors suggesting potential relationships between GABA-A receptor variations and capacity to undergo tDCS-induced cortical plasticity. In the largest tDCS study of its kind, this study presents an important step forward in determining the contribution genetic factors play in previously observed inter-individual variability to tDCS.
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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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30
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Shires J, Carrasco C, Berryhill ME. No tDCS augmented working memory training benefit in undergraduates rewarded with course credit. Brain Stimul 2020; 13:1524-1526. [PMID: 32891871 DOI: 10.1016/j.brs.2020.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 08/31/2020] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND The goal of working memory (WM) training is to expand capacity of this executive function. Transcranial direct current stimulation (tDCS) paired with WM training is more consistent than either alone. We have reported that tDCS targeting frontal and/or parietal regions enhanced theta phase locking, reduced alpha power, and strengthened theta-gamma phase amplitude coupling. OBJECTIVE To determine whether tDCS to frontal or parietal sites optimized WM training gains we pre-registered a tDCS-WM training study. METHODS 80 undergraduates were randomly assigned to one of four anodal tDCS montages: frontal (F4), parietal (P4), alternating (P4-F4), and sham (P4 or F4). Participants completed 5-training sessions over one week and returned for follow-up testing after 30 days of no-contact. RESULTS No group showed significant improvement in trained or transfer task performance at the end of training nor at follow-up. CONCLUSIONS This null finding marks a failure to replicate in undergraduates training benefits observed in graduate students. We argue that motivation is essential to elicit improved performance in training protocols.
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Affiliation(s)
- Jorja Shires
- University of Nevada, Program in Cognitive and Brain Sciences, Department of Psychology, Reno, NV, 89557, USA
| | - Carlos Carrasco
- University of Nevada, Program in Cognitive and Brain Sciences, Department of Psychology, Reno, NV, 89557, USA; University of California, Davis, Program in Neuroscience, Davis, CA, 95616, USA
| | - Marian E Berryhill
- University of Nevada, Program in Cognitive and Brain Sciences, Department of Psychology, Reno, NV, 89557, USA.
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Non-invasive Brain Stimulation Effects on the Perceptual and Cognitive Processes Underlying Decision-making: a Mini Review. JOURNAL OF COGNITIVE ENHANCEMENT 2020. [DOI: 10.1007/s41465-020-00186-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Transcranial direct current stimulation and working memory: Comparison of effect on learning shapes and English letters. PLoS One 2020; 15:e0222688. [PMID: 32706780 PMCID: PMC7380606 DOI: 10.1371/journal.pone.0222688] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 06/25/2020] [Indexed: 11/25/2022] Open
Abstract
We present the results of a study investigating whether there is an effect of Anodal-Transcranial Direct Current Stimulation (A-tDCS) on working memory (WM) performance. The relative effectiveness of A-tDCS on WM is investigated using a 2-back test protocol using two commonly used memory visual stimuli (shapes and letters). In a double-blinded, randomised, crossover, sham-controlled experiment, real A-tDCS and sham A-tDCS were applied separately to the left dorsolateral prefrontal cortex (L-DLPFC) of twenty healthy subjects. There was a minimal interval of one week between sham and real A-tDCS sessions. For the letters based stimulus experiment, 2-back test recall accuracy was measured for a set of English letters (A-L) which were presented individually in a randomised order where each was separated by a blank interval. A similar 2-back protocol was used for the shapes based stimuli experiment where instead of letters, a set of 12 geometric shapes were used. The working memory accuracy scores measured appeared to be significantly affected by memory stimulus type used and by the application of A-tDCS (repeated measures ANOVA p<0.05). A large effect size (d = 0.98) and statistical significance between sham and real A-tDCS WM scores (p = 0.01) was found when shapes were used as a visual testing stimulus, while low (d = 0.38) effect size and insignificant difference (p = 0.15) was found when letters were used. This results are important as they show that recollection different stimuli used in working memory can be affected differently by A-tDCS application. This highlights the importance of considering using multiple methods of WM testing when assessing the effectiveness of A-tDCS.
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Hanley CJ, Alderman SL, Clemence E. Optimising Cognitive Enhancement: Systematic Assessment of the Effects of tDCS Duration in Older Adults. Brain Sci 2020; 10:brainsci10050304. [PMID: 32429366 PMCID: PMC7287828 DOI: 10.3390/brainsci10050304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 12/31/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) has been shown to support cognition and brain function in older adults. However, there is an absence of research specifically designed to determine optimal stimulation protocols, and much of what is known about subtle distinctions in tDCS parameters is based on young adult data. As the first systematic exploration targeting older adults, this study aimed to provide insight into the effects of variations in stimulation duration. Anodal stimulation of 10 and 20 min, as well as a sham-control variant, was administered to dorsolateral prefrontal cortex. Stimulation effects were assessed in relation to a novel attentional control task. Ten minutes of anodal stimulation significantly improved task-switching speed from baseline, contrary to the sham-control and 20 min variants. The findings represent a crucial step forwards for methods development, and the refinement of stimulation to enhance executive function in the ageing population.
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Patel R, Dawidziuk A, Darzi A, Singh H, Leff DR. Systematic review of combined functional near-infrared spectroscopy and transcranial direct-current stimulation studies. NEUROPHOTONICS 2020; 7:020901. [PMID: 32607389 PMCID: PMC7315225 DOI: 10.1117/1.nph.7.2.020901] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/15/2020] [Indexed: 05/05/2023]
Abstract
Significance: Combining transcranial direct-current stimulation (tDCS) with functional near-infrared spectroscopy (fNIRS) is a recent approach to exploring brain activation evoked by neurostimulation. Aim: To critically evaluate studies combining tDCS and fNIRS and provide a consolidated overview of cortical hemodynamic responses to neurostimulation. Approach: Key terms were searched in three databases (MEDLINE, EMBASE, and PsycINFO) with cross-referencing and works from Google Scholar also evaluated. All studies reporting on fNIRS-derived hemoglobin changes evoked by tDCS were included. Results: Literature searches revealed 474 articles, of which 28 were included for final review (22 in healthy individuals: 9 involving rest and 13 with tasks; 6 in the clinical setting). At rest, an overall increase in cortical activation was observed in fNIRS responses at the site of stimulation, with evidence suggesting nonstimulated brain regions are also similarly affected. Conversely, during tasks, reduced cortical activation was observed during online stimulation. Offline and poststimulation effects were less consistent, as is the impact on clinical populations and their symptom correlation. Conclusion: This review explores the methodological frameworks for fNIRS-tDCS evaluations and summarizes hemodynamic responses associated with tDCS in all populations. Our findings provide further evidence of the impact of tDCS on neuronal activation within functionally connected networks.
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Affiliation(s)
- Ronak Patel
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
- Address all correspondence to Ronak Patel, E-mail:
| | - Aleksander Dawidziuk
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
| | - Ara Darzi
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
| | - Harsimrat Singh
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
| | - Daniel Richard Leff
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
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Rushby JA, De Blasio FM, Logan JA, Wearne T, Kornfeld E, Wilson EJ, Loo C, Martin D, McDonald S. tDCS effects on task-related activation and working memory performance in traumatic brain injury: A within group randomized controlled trial. Neuropsychol Rehabil 2020; 31:814-836. [PMID: 32114899 DOI: 10.1080/09602011.2020.1733620] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Non-invasive transcranial direct current stimulation (tDCS) has been reported to facilitate working memory in normal adults. There is some evidence in people with Traumatic Brain Injury (TBI) but overall evidence is mixed. This study aimed to address shortcomings of prior study designs in TBI to examine whether a single dose of tDCS would lead to benefits in working memory. Thirty people with severe, chronic TBI were administered a single session of either anodal tDCS (2 mA for 20 min) or sham tDCS (2 mA for 30 s), in a counterbalanced order, over the left parietal cortex while performing 1-back and 2-back working memory tasks. Skin conductance levels were examined as a measure of task activated arousal, a possible functional analogue of cortical excitability. We found that tDCS led to no improvements in accuracy on the working memory tasks. A slight increase in variability and reaction time with tDCS was related to decreased task activated arousal. Overall, this study yielded no evidence that a single session of tDCS can facilitate working memory for people with TBI.
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Affiliation(s)
| | | | - Jodie A Logan
- School of Psychology, University of New South Wales, Sydney, Australia
| | - Travis Wearne
- School of Psychology, University of New South Wales, Sydney, Australia
| | - Emma Kornfeld
- School of Psychology, University of New South Wales, Sydney, Australia
| | - Emily Jane Wilson
- School of Psychology, University of New South Wales, Sydney, Australia
| | - Colleen Loo
- School of Psychiatry & Black Dog Institute, University of New South Wales, Sydney, Australia
| | - Donel Martin
- School of Psychiatry & Black Dog Institute, University of New South Wales, Sydney, Australia
| | - Skye McDonald
- School of Psychology, University of New South Wales, Sydney, Australia
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36
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A Review of US Army Research Contributing to Cognitive Enhancement in Military Contexts. JOURNAL OF COGNITIVE ENHANCEMENT 2020. [DOI: 10.1007/s41465-020-00167-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Visual working memory deficits in undergraduates with a history of mild traumatic brain injury. Atten Percept Psychophys 2020; 81:2597-2603. [PMID: 31218600 DOI: 10.3758/s13414-019-01774-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We investigated whether a history of mild traumatic brain injury (mTBI), or concussion, has any effect on visual working memory (WM) performance. In most cases, cognitive performance is thought to return to premorbid levels soon after injury, without further medical intervention. We tested this assumption in undergraduates, among whom a history of mTBI is prevalent. Notably, participants with a history of mTBI performed worse than their colleagues with no such history. Experiment 1 was based on a change detection paradigm in which we manipulated visual WM set size from one to three items, which revealed a significant deficit at set size 3. In Experiment 2 we investigated whether feedback could rescue WM performance in the mTBI group, and found that it failed. In Experiment 3 we manipulated WM maintenance duration (set size 3, 500-1,500 ms) to investigate a maintenance-related deficit. Across all durations, the mTBI group was impaired. In Experiment 4 we tested whether retrieval demands contributed to WM deficits and showed a consistent deficit across recognition and recall probes. In short, even years after an mTBI, undergraduates perform differently on visual WM tasks than their peers with no such history. Given the prevalence of mTBI, these data may benefit other researchers who see high variability in their data. Clearly, further studies will be needed to determine the breadth of the cognitive deficits in those with a history of mTBI and to identify relevant factors that contribute to positive cognitive outcomes.
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Jones KT, Johnson EL, Berryhill ME. Frontoparietal theta-gamma interactions track working memory enhancement with training and tDCS. Neuroimage 2020; 211:116615. [PMID: 32044440 PMCID: PMC7733399 DOI: 10.1016/j.neuroimage.2020.116615] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/14/2020] [Accepted: 02/05/2020] [Indexed: 01/17/2023] Open
Abstract
Despite considerable interest in enhancing, preserving, and rehabilitating working memory (WM), efforts to elicit sustained behavioral improvements have been met with limited success. Here, we paired WM training with transcranial direct current stimulation (tDCS) to the frontoparietal network over four days. Active tDCS enhanced WM performance by modulating interactions between frontoparietal theta oscillations and gamma activity, as measured by pre- and post-training high-density electroencephalography (EEG). Increased phase-amplitude coupling (PAC) between the prefrontal stimulation site and temporo-parietal gamma activity explained behavioral improvements, and was most effective when gamma occurred near the prefrontal theta peak. These results demonstrate for the first time that tDCS-linked WM training elicits lasting changes in behavior by optimizing the oscillatory substrates of prefrontal control.
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Affiliation(s)
- Kevin T Jones
- University of Nevada-Reno, Department of Psychology, Cognitive and Brain Sciences, Reno, NV, 89557, USA; University of California-San Francisco, Department of Neurology, Neuroscape, San Francisco, CA, 94158, USA
| | - Elizabeth L Johnson
- University of California-Berkeley, Helen Wills Neuroscience Institute, Berkeley, CA, 94720, USA; Wayne State University, Institute of Gerontology, Life-Span Cognitive Neuroscience Program, Detroit, MI, 48202, USA
| | - Marian E Berryhill
- University of Nevada-Reno, Department of Psychology, Cognitive and Brain Sciences, Reno, NV, 89557, USA.
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Di Rosa E, Brigadoi S, Cutini S, Tarantino V, Dell'Acqua R, Mapelli D, Braver TS, Vallesi A. Reward motivation and neurostimulation interact to improve working memory performance in healthy older adults: A simultaneous tDCS-fNIRS study. Neuroimage 2019; 202:116062. [PMID: 31369810 DOI: 10.1016/j.neuroimage.2019.116062] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 07/25/2019] [Accepted: 07/27/2019] [Indexed: 01/12/2023] Open
Abstract
Several studies have evaluated the effect of anodal transcranial direct current stimulation (tDCS) over the prefrontal cortex (PFC) for the enhancement of working memory (WM) performance in healthy older adults. However, the mixed results obtained so far suggest the need for concurrent brain imaging, in order to more directly examine tDCS effects. The present study adopted a continuous multimodal approach utilizing functional near-infrared spectroscopy (fNIRS) to examine the interactive effects of tDCS combined with manipulations of reward motivation. Twenty-one older adults (mean age = 69.7 years; SD = 5.05) performed an experimental visuo-spatial WM task before, during and after the delivery of 1.5 mA anodal tDCS/sham over the left prefrontal cortex (PFC). During stimulation, participants received performance-contingent reward for every fast and correct response during the WM task. In both sessions, hemodynamic activity of the bilateral frontal, motor and parietal areas was recorded across the entire duration of the WM task. Cognitive functions and reward sensitivity were also assessed with standard measures. Results demonstrated a significant impact of tDCS on both WM performance and hemodynamic activity. Specifically, faster responses in the WM task were observed both during and after anodal tDCS, while no differences were found under sham control conditions. However, these effects emerged only when taking into account individual visuo-spatial WM capacity. Additionally, during and after the anodal tDCS, increased hemodynamic activity relative to sham was observed in the bilateral PFC, while no effects of tDCS were detected in the motor and parietal areas. These results provide the first evidence of tDCS-dependent functional changes in PFC activity in healthy older adults during the execution of a WM task. Moreover, they highlight the utility of combining reward motivation with prefrontal anodal tDCS, as a potential strategy to improve WM efficiency in low performing healthy older adults.
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Affiliation(s)
- Elisa Di Rosa
- Department of Neuroscience & Padova Neuroscience Center, University of Padova, Padova, Italy; Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, USA.
| | - Sabrina Brigadoi
- Department of Developmental Psychology, University of Padova, Padova, Italy; Department of Information Engineering, University of Padova, Padova, Italy
| | - Simone Cutini
- Department of Developmental Psychology, University of Padova, Padova, Italy; Padova Neuroscience Center, University of Padova, Padova, Italy
| | - Vincenza Tarantino
- Department of Neuroscience & Padova Neuroscience Center, University of Padova, Padova, Italy; Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Roberto Dell'Acqua
- Department of Developmental Psychology, University of Padova, Padova, Italy; Padova Neuroscience Center, University of Padova, Padova, Italy
| | - Daniela Mapelli
- Department of General Psychology, University of Padova, Padova, Italy
| | - Todd S Braver
- Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, USA
| | - Antonino Vallesi
- Department of Neuroscience & Padova Neuroscience Center, University of Padova, Padova, Italy; Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
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40
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Brunyé TT, Hussey EK, Fontes EB, Ward N. Modulating Applied Task Performance via Transcranial Electrical Stimulation. Front Hum Neurosci 2019; 13:140. [PMID: 31114491 PMCID: PMC6503100 DOI: 10.3389/fnhum.2019.00140] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/10/2019] [Indexed: 11/28/2022] Open
Abstract
Basic and applied research are increasingly adopting transcranial electrical stimulation (tES) for modulating perceptual, cognitive, affective, and motor processes. Industry and defense applications of tES hold potential for accelerating training and knowledge acquisition and sustaining work-related performance in the face of fatigue, workload, and stress. This mini-review article describes the promises and perils of tES, and reviews research testing its influence on two broad applied areas: sustaining and dividing attention, and operating in virtual environments. Also included is a discussion of challenges related to viable mechanistic explanations for tES effectiveness, attempts at replication and consideration of null results, and the potential importance of individual differences in predicting tES influences on human performance. Finally, future research directions are proposed to address these challenges and help develop a fuller understanding of tES viability for enhancing real-world performance.
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Affiliation(s)
- Tad T Brunyé
- Center for Applied Brain and Cognitive Sciences, School of Engineering, Tufts University, Medford, MA, United States.,U.S. Army Combat Capabilities Development Command, Soldier Center (CCDC-SC), Natick, MA, United States.,Department of Psychology, Tufts University, Medford, MA, United States
| | - Erika K Hussey
- Center for Applied Brain and Cognitive Sciences, School of Engineering, Tufts University, Medford, MA, United States.,U.S. Army Combat Capabilities Development Command, Soldier Center (CCDC-SC), Natick, MA, United States
| | - Eduardo B Fontes
- Department of Psychology, Tufts University, Medford, MA, United States.,NEUROEX-Research Group in Physical Activity, Cognition and Behavior, Health Science Center, Department of Physical Education, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Nathan Ward
- Department of Psychology, Tufts University, Medford, MA, United States.,NEUROEX-Research Group in Physical Activity, Cognition and Behavior, Health Science Center, Department of Physical Education, Federal University of Rio Grande do Norte, Natal, Brazil
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41
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Yang M, Yang Z, Yuan T, Feng W, Wang P. A Systemic Review of Functional Near-Infrared Spectroscopy for Stroke: Current Application and Future Directions. Front Neurol 2019; 10:58. [PMID: 30804877 PMCID: PMC6371039 DOI: 10.3389/fneur.2019.00058] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/16/2019] [Indexed: 02/05/2023] Open
Abstract
Background: Survivors of stroke often experience significant disability and impaired quality of life. The recovery of motor or cognitive function requires long periods. Neuroimaging could measure changes in the brain and monitor recovery process in order to offer timely treatment and assess the effects of therapy. A non-invasive neuroimaging technique near-infrared spectroscopy (NIRS) with its ambulatory, portable, low-cost nature without fixation of subjects has attracted extensive attention. Methods: We conducted a comprehensive literature review in order to review the use of NIRS in stroke or post-stroke patients in July 2018. NCBI Pubmed database, EMBASE database, Cochrane Library and ScienceDirect database were searched. Results: Overall, we reviewed 66 papers. NIRS has a wide range of application, including in monitoring upper limb, lower limb recovery, motor learning, cortical function recovery, cerebral hemodynamic changes, cerebral oxygenation, as well as in therapeutic method, clinical researches, and evaluation of the risk for stroke. Conclusions: This study provides a preliminary evidence of the application of NIRS in stroke patients as a monitoring, therapeutic, and research tool. Further studies could give more emphasize on the combination of NIRS with other techniques and its utility in the prevention of stroke.
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Affiliation(s)
- Muyue Yang
- Department of Rehabilitation Medicine, Ruijin Hospital, Shanghai, China.,School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhen Yang
- Core Facility of West China Hospital, Sichuan University, Chengdu, China
| | - Tifei Yuan
- Shanghai Mental Health Centre, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wuwei Feng
- Department of Neurology, Medical University of South Carolina, Charleston, SC, United States
| | - Pu Wang
- Department of Rehabilitation Medicine, Ruijin Hospital, Shanghai, China
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42
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Rabipour S, Vidjen PS, Remaud A, Davidson PSR, Tremblay F. Examining the Interactions Between Expectations and tDCS Effects on Motor and Cognitive Performance. Front Neurosci 2019; 12:999. [PMID: 30666182 PMCID: PMC6330301 DOI: 10.3389/fnins.2018.00999] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/11/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Despite a growing literature and commercial market, the effectiveness of transcranial direct current stimulation (tDCS) remains questionable. Notably, studies rarely examine factors such as expectations of outcomes, which may influence tDCS response through placebo-like effects. Here we sought to determine whether expectations could influence the behavioral outcomes of a tDCS intervention. Methods: Through an initial study and self-replication, we recruited 121 naïve young adults 18-34 years of age (M = 21.14, SD = 3.58; 88 women). We evaluated expectations of tDCS and of motor and cognitive performance at three times: (i) at baseline; (ii) after being primed to have High or Low expectations of outcomes; and (iii) after a single session of sham-controlled anodal tDCS over the left or right motor cortex. Before and after stimulation, participants performed the Grooved Pegboard Test and a choice reaction time task as measures of motor dexterity, response time, and response inhibition. Results: Repeated measures ANOVA revealed that participants had varying, largely uncertain, expectations regarding tDCS effectiveness at baseline. Expectation ratings significantly increased or decreased in response to High or Low priming, respectively, and decreased following the intervention. Response times and accuracy on motor and cognitive measures were largely unaffected by expectation or stimulation conditions. Overall, our analysis revealed no effect attributable to baseline expectations, belief of group assignment, or experimental condition on behavioral outcomes. Subjective experience did not differ based on expectation or stimulation condition. Conclusions: Our results suggest no clear effects of tDCS or of expectations on our performance measures, highlighting the need for further investigations of such stimulation methods.
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Affiliation(s)
- Sheida Rabipour
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | | | - Anthony Remaud
- Bruyère Research Institute, Bruyère Continuing Care, Ottawa, ON, Canada
| | - Patrick S. R. Davidson
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
- Bruyère Research Institute, Bruyère Continuing Care, Ottawa, ON, Canada
| | - François Tremblay
- Bruyère Research Institute, Bruyère Continuing Care, Ottawa, ON, Canada
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43
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Brunyé TT, Smith AM, Horner CB, Thomas AK. Verbal long-term memory is enhanced by retrieval practice but impaired by prefrontal direct current stimulation. Brain Cogn 2018; 128:80-88. [PMID: 30414699 DOI: 10.1016/j.bandc.2018.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/13/2018] [Accepted: 09/25/2018] [Indexed: 10/27/2022]
Abstract
Retrieval practice involves repeatedly testing a student during the learning experience, reliably conferring learning advantages relative to repeated study. Transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (dlPFC) has also been shown to confer learning advantages for verbal memory, though research is equivocal. The present study examined the effects of retrieval versus study practice with or without left dlPFC tDCS on verbal episodic memory. Participants (N = 150) experienced either retrieval practice or study practice, and active anodal, active cathodal, or sham tDCS while encoding word lists, and then returned two days later for a final recall test. Three primary patterns emerged: first, during encoding, tDCS did not influence recall rates in the retrieval practice group. Second, during final recall, participants in the retrieval practice groups recalled more than those in the study practice groups. Finally, during final recall, anodal tDCS decreased recall relative to sham and cathodal stimulation, suggesting that it interfered with developing highly detailed memories that could be relied upon for subsequent recollection. Data support existing research demonstrating the effectiveness of retrieval practice as a learning strategy, but also suggest that anodal dlPFC stimulation can induce long-term negative impacts on verbal episodic memory retrieval.
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Affiliation(s)
- Tad T Brunyé
- Tufts University, Center for Applied Brain & Cognitive Sciences, Medford, MA 02155, USA; Tufts University, Department of Psychology, Medford, MA 02155, USA; U.S. Army Natick Soldier RDEC, Cognitive Sciences, Natick, MA 01760, USA.
| | - Amy M Smith
- Tufts University, Center for Applied Brain & Cognitive Sciences, Medford, MA 02155, USA
| | - Carlene B Horner
- Tufts University, Center for Applied Brain & Cognitive Sciences, Medford, MA 02155, USA
| | - Ayanna K Thomas
- Tufts University, Department of Psychology, Medford, MA 02155, USA
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44
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Rabipour S, Wu AD, Davidson PS, Iacoboni M. Expectations may influence the effects of transcranial direct current stimulation. Neuropsychologia 2018; 119:524-534. [DOI: 10.1016/j.neuropsychologia.2018.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 01/05/2023]
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45
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Antonenko D, Nierhaus T, Meinzer M, Prehn K, Thielscher A, Ittermann B, Flöel A. Age-dependent effects of brain stimulation on network centrality. Neuroimage 2018; 176:71-82. [DOI: 10.1016/j.neuroimage.2018.04.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/13/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022] Open
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46
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Westwood SJ, Romani C. Null Effects on Working Memory and Verbal Fluency Tasks When Applying Anodal tDCS to the Inferior Frontal Gyrus of Healthy Participants. Front Neurosci 2018; 12:166. [PMID: 29615855 PMCID: PMC5867342 DOI: 10.3389/fnins.2018.00166] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/01/2018] [Indexed: 01/22/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a technique used to modify cognition by modulating underlying cortical excitability via weak electric current applied through the scalp. Although many studies have reported positive effects with tDCS, a number of recent studies highlight that tDCS effects can be small and difficult to reproduce. This is especially the case when attempting to modulate performance using single applications of tDCS in healthy participants. Possible reasons may be that optimal stimulation parameters have yet to be identified, and that individual variation in cortical activity and/or level of ability confound outcomes. To address these points, we carried out a series of experiments in which we attempted to modulate performance in fluency and working memory probe tasks using stimulation parameters which have been associated with positive outcomes: we targeted the left inferior frontal gyrus (LIFG) and compared performance when applying a 1.5 mA anodal current for 25 min and with sham stimulation. There is evidence that LIFG plays a role in these tasks and previous studies have found positive effects of stimulation. We also compared our experimental group (N = 19–20) with a control group receiving no stimulation (n = 24). More importantly, we also considered effects on subgroups subdivided according to memory span as well as to more direct measures of executive function abilities and motivational levels. We found no systematic effect of stimulation. Our findings are in line with a growing body of evidence that tDCS produces unreliable effects. We acknowledge that our findings speak to the conditions we investigated, and that alternative protocols (e.g., multiple sessions, clinical samples, and different stimulation polarities) may be more effective. We encourage further research to explore optimal conditions for tDCS efficacy, given the potential benefits that this technique poses for understanding and enhancing cognition.
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Affiliation(s)
- Samuel J Westwood
- School of Life & Health Sciences, Aston University, Birmingham, United Kingdom
| | - Cristina Romani
- School of Life & Health Sciences, Aston University, Birmingham, United Kingdom
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47
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Arciniega H, Gözenman F, Jones KT, Stephens JA, Berryhill ME. Frontoparietal tDCS Benefits Visual Working Memory in Older Adults With Low Working Memory Capacity. Front Aging Neurosci 2018; 10:57. [PMID: 29593522 PMCID: PMC5859363 DOI: 10.3389/fnagi.2018.00057] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 02/20/2018] [Indexed: 01/09/2023] Open
Abstract
Working memory (WM) permits maintenance of information over brief delays and is an essential executive function. Unfortunately, WM is subject to age-related decline. Some evidence supports the use of transcranial direct current stimulation (tDCS) to improve visual WM. A gap in knowledge is an understanding of the mechanism characterizing these tDCS linked effects. To address this gap, we compared the effects of two tDCS montages designed on visual working memory (VWM) performance. The bifrontal montage was designed to stimulate the heightened bilateral frontal activity observed in aging adults. The unilateral frontoparietal montage was designed to stimulate activation patterns observed in young adults. Participants completed three sessions (bilateral frontal, right frontoparietal, sham) of anodal tDCS (20 min, 2 mA). During stimulation, participants performed a visual long-term memory (LTM) control task and a visual WM task. There was no effect of tDCS on the LTM task. Participants receiving right unilateral tDCS showed a WM benefit. This pattern was most robust in older adults with low WM capacity. To address the concern that the key difference between the two tDCS montages could be tDCS over the posterior parietal cortex (PPC), we included new analyses from a previous study applying tDCS targeting the PPC paired with a recognition VWM task. No significant main effects were found. A subsequent experiment in young adults found no significant effect of either tDCS montage on either task. These data indicate that tDCS montage, age and WM capacity should be considered when designing tDCS protocols. We interpret these findings as suggestive that protocols designed to restore more youthful patterns of brain activity are superior to those that compensate for age-related changes.
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Affiliation(s)
- Hector Arciniega
- Memory and Brain Laboratory, Department of Psychology, Program in Cognitive and Brain Sciences, and Integrative Neuroscience, University of Nevada, Reno, NV, United States
| | - Filiz Gözenman
- Department of Psychology, Yaşar University, İzmir, Turkey
| | - Kevin T. Jones
- Department of Psychology, Colorado State University, Fort Collins, CO, United States
| | - Jaclyn A. Stephens
- Department of Occupational Therapy, Colorado State University, Fort Collins, CO, United States
| | - Marian E. Berryhill
- Memory and Brain Laboratory, Department of Psychology, Program in Cognitive and Brain Sciences, and Integrative Neuroscience, University of Nevada, Reno, NV, United States
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48
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Shuster LI. Considerations for the Use of Neuroimaging Technologies for Predicting Recovery of Speech and Language in Aphasia. AMERICAN JOURNAL OF SPEECH-LANGUAGE PATHOLOGY 2018; 27:291-305. [PMID: 29497745 DOI: 10.1044/2018_ajslp-16-0180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/16/2018] [Indexed: 06/08/2023]
Abstract
PURPOSE The number of research articles aimed at identifying neuroimaging biomarkers for predicting recovery from aphasia continues to grow. Although the clinical use of these biomarkers to determine prognosis has been proposed, there has been little discussion of how this would be accomplished. This is an important issue because the best translational science occurs when translation is considered early in the research process. The purpose of this clinical focus article is to present a framework to guide the discussion of how neuroimaging biomarkers for recovery from aphasia could be implemented clinically. METHOD The genomics literature reveals that implementing genetic testing in the real-world poses both opportunities and challenges. There is much similarity between these opportunities and challenges and those related to implementing neuroimaging testing to predict recovery in aphasia. Therefore, the Center for Disease Control's model list of questions aimed at guiding the review of genetic testing has been adapted to guide the discussion of using neuroimaging biomarkers as predictors of recovery in aphasia. CONCLUSION The adapted model list presented here is a first and useful step toward initiating a discussion of how neuroimaging biomarkers of recovery could be employed clinically to provide improved quality of care for individuals with aphasia.
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Affiliation(s)
- Linda I Shuster
- Department of Speech, Language, and Hearing Sciences, Western Michigan University, Kalamazoo
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49
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Greenwood PM, Blumberg EJ, Scheldrup MR. Hypothesis for cognitive effects of transcranial direct current stimulation: Externally- and internally-directed cognition. Neurosci Biobehav Rev 2018; 86:226-238. [DOI: 10.1016/j.neubiorev.2017.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 11/24/2022]
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50
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Hurley R, Machado L. Using transcranial direct current stimulation to improve verbal working memory: A detailed review of the methodology. J Clin Exp Neuropsychol 2018; 40:790-804. [DOI: 10.1080/13803395.2018.1434133] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Roanne Hurley
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Liana Machado
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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