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Laakso I, Tani K, Gomez-Tames J, Hirata A, Tanaka S. Small effects of electric field on motor cortical excitability following anodal tDCS. iScience 2024; 27:108967. [PMID: 38352229 PMCID: PMC10863330 DOI: 10.1016/j.isci.2024.108967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/05/2023] [Accepted: 01/16/2024] [Indexed: 02/16/2024] Open
Abstract
The dose-response characteristics of transcranial direct current stimulation (tDCS) remain uncertain but may be related to variability in brain electric fields due to individual anatomical factors. Here, we investigated whether the electric fields influence the responses to motor cortical tDCS. In a randomized cross-over design, 21 participants underwent 10 min of anodal tDCS with 0.5, 1.0, 1.5, or 2.0 mA or sham. Compared to sham, all active conditions increased the size of motor evoked potentials (MEP) normalized to the pre-tDCS baseline, irrespective of anterior or posterior magnetic test stimuli. The electric field calculated in the motor cortex of each participant had a nonlinear effect on the normalized MEP size, but its effects were small compared to those of other participant-specific factors. The findings support the efficacy of anodal tDCS in enhancing the MEP size but do not demonstrate any benefits of personalized electric field modeling in explaining tDCS response variability.
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Affiliation(s)
- Ilkka Laakso
- Department of Electrical Engineering and Automation, Aalto University, 02150 Espoo, Finland
| | - Keisuke Tani
- Faculty of Psychology, Otemon Gakuin University, Ibaraki, Osaka 567-8502, Japan
| | - Jose Gomez-Tames
- Department of Medical Engineering, Graduate School of Engineering, Chiba University, Chiba 263-8522, Japan
| | - Akimasa Hirata
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
- Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Satoshi Tanaka
- Laboratory of Psychology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3125, Japan
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Shoaib Z, Chang WK, Lee J, Lee SH, Phillips V Z, Lee SH, Paik NJ, Hwang HJ, Kim WS. Investigation of Neuromodulatory Effect of Anodal Cerebellar Transcranial Direct Current Stimulation on the Primary Motor Cortex Using Functional Near-Infrared Spectroscopy. CEREBELLUM (LONDON, ENGLAND) 2024; 23:56-66. [PMID: 36633829 DOI: 10.1007/s12311-023-01511-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/03/2023] [Indexed: 01/13/2023]
Abstract
Cerebellar brain inhibition (CBI), a neural connection between the cerebellum and primary motor cortex (M1), has been researched as a target pathway for neuromodulation to improve clinical outcomes in various neurological diseases. However, conflicting results of anodal cerebellar transcranial direct current stimulation (acb-tDCS) on M1 excitability indicate that additional investigation is required to examine its precise effect. This study aimed to gather evidence of the neuromodulatory effect of acb-tDCS on the M1 using functional near-infrared spectroscopy (fNIRS). Sixteen healthy participants were included in this cross-over study. Participants received real and sham acb-tDCS randomly, with a minimum 1-week washout period between them. The anode and cathode were placed on the right cerebellum and the right buccinator muscle, respectively. Stimulation lasted 20 min at an intensity of 2 mA, and fNIRS data were recorded for 42 min (including a 4-min baseline before stimulation and an 18-min post-stimulation duration) using eight channels attached bilaterally on the M1. acb-tDCS induced a significant decrease in oxyhemoglobin (HbO) concentration (inhibitory effect) in the left (contralateral) M1, whereas it induced a significant increase in HbO concentration (excitatory effect) in the right (ipsilateral) M1 compared to sham tDCS during (p < 0.05) and after stimulation (p < 0.01) in a group level analysis. At the individual level, variations in response to acb-tDCS were observed. Our findings demonstrate the neuromodulatory effects of acb-tDCS on the bilateral M1 in terms of neuronal hemodynamics.
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Affiliation(s)
- Zeshan Shoaib
- Department of Electronics and Information Engineering, Korea University, Sejong City, South Korea
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Won Kee Chang
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Jongseung Lee
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Stephanie Hyeyoung Lee
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Zephaniah Phillips V
- Global Health Technology Research Center, College of Health Science, Korea University, Seoul, South Korea
| | - Seung Hyun Lee
- Interdisciplinary Program in Precision Public Health, Korea University, Seoul, South Korea
| | - Nam-Jong Paik
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Han-Jeong Hwang
- Department of Electronics and Information Engineering, Korea University, Sejong City, South Korea.
- Interdisciplinary Graduate Program for Artificial Intelligence Smart Convergence Technology, Korea University, Sejong City, South Korea.
| | - Won-Seok Kim
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
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3
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Chan YH, Chang HM, Lu ML, Goh KK. Targeting cravings in substance addiction with transcranial direct current stimulation: insights from a meta-analysis of sham-controlled trials. Psychiatry Res 2024; 331:115621. [PMID: 38043411 DOI: 10.1016/j.psychres.2023.115621] [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] [Received: 06/24/2023] [Revised: 10/06/2023] [Accepted: 11/19/2023] [Indexed: 12/05/2023]
Abstract
Addiction is a substantial health concern; craving-the core symptom of addiction-is strongly associated with relapse. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that reduces cravings by altering cortical excitability and connectivity in brain regions. This systematic review and meta-analysis was conducted (following the PRISMA guidelines) to evaluate the efficacy of tDCS in reducing cravings for substances. Our analysis included 43 randomized, sham-controlled trials involving 1,095 and 913 participants receiving tDCS and sham stimulation, respectively. We analyzed the changes in craving scores and found that tDCS led to a moderate reduction in cravings compared with the sham effects. This effect was particularly pronounced when bilateral stimulation was used, the anodal electrode was placed on the right dorsolateral prefrontal cortex, current intensities ranged from 1.5 to 2 mA, stimulation sessions lasted 20 minutes, and the electrodes size was ≥35 cm². Notably, tDCS effectively reduced cravings for opioids, methamphetamine, cocaine, and tobacco but not for alcohol or cannabis. Our findings indicate tDCS as a promising, noninvasive, and low-risk intervention for reducing cravings for opioids, methamphetamine, cocaine, and tobacco. Additional studies are warranted to refine stimulation parameters and evaluate the long-term efficacy of tDCS in managing substance cravings.
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Affiliation(s)
- Yi-Hsun Chan
- Department of Psychiatry, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Hu-Ming Chang
- Department of Addiction Sciences, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan; Psychiatric Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Mong-Liang Lu
- Department of Psychiatry, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Psychiatric Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Kah Kheng Goh
- Department of Psychiatry, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Psychiatric Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Injury Prevention and Control, College of Public Health, Taipei Medical University, Taipei, Taiwan; The Innovative and Translational Research Center for Brain Consciousness, Taipei Medical University, Taipei, Taiwan.
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4
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Caccianiga G, Mooney RA, Celnik PA, Cantarero GL, Brown JD. Anodal cerebellar t-DCS impacts skill learning and transfer on a robotic surgery training task. Sci Rep 2023; 13:21394. [PMID: 38123594 PMCID: PMC10733429 DOI: 10.1038/s41598-023-47404-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023] Open
Abstract
The cerebellum has demonstrated a critical role during adaptation in motor learning. However, the extent to which it can contribute to the skill acquisition of complex real-world tasks remains unclear. One particularly challenging application in terms of motor activities is robotic surgery, which requires surgeons to complete complex multidimensional visuomotor tasks through a remotely operated robot. Given the need for high skill proficiency and the lack of haptic feedback, there is a pressing need for understanding and improving skill development. We investigated the effect of cerebellar transcranial direct current stimulation applied during the execution of a robotic surgery training task. Study participants received either real or sham stimulation while performing a needle driving task in a virtual (simulated) and a real-world (actual surgical robot) setting. We found that cerebellar stimulation significantly improved performance compared to sham stimulation at fast (more demanding) execution speeds in both virtual and real-world training settings. Furthermore, participants that received cerebellar stimulation more effectively transferred the skills they acquired during virtual training to the real world. Our findings underline the potential of non-invasive brain stimulation to enhance skill learning and transfer in real-world relevant tasks and, more broadly, its potential for improving complex motor learning.
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Affiliation(s)
- Guido Caccianiga
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, 21218, USA.
- Haptic Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, 70569, Germany.
| | - Ronan A Mooney
- Department of Physical Medicine and Rehabilitation, John Hopkins Medical Institute, Baltimore, 21218, USA
| | - Pablo A Celnik
- Department of Physical Medicine and Rehabilitation, John Hopkins Medical Institute, Baltimore, 21218, USA
- Shirley Ryan AbilityLab, Chicago, 60611, USA
| | - Gabriela L Cantarero
- Department of Physical Medicine and Rehabilitation, John Hopkins Medical Institute, Baltimore, 21218, USA
| | - Jeremy D Brown
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, 21218, USA
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Müller D, Habel U, Brodkin ES, Clemens B, Weidler C. HD-tDCS induced changes in resting-state functional connectivity: Insights from EF modeling. Brain Stimul 2023; 16:1722-1732. [PMID: 38008154 DOI: 10.1016/j.brs.2023.11.012] [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: 08/25/2023] [Revised: 11/19/2023] [Accepted: 11/20/2023] [Indexed: 11/28/2023] Open
Abstract
BACKGROUND High-definition transcranial direct current stimulation (HD-tDCS) holds promise for therapeutic use in psychiatric disorders. One obstacle for the implementation into clinical practice is response variability. One way to tackle this obstacle is the use of Individualized head models. OBJECTIVE This study investigated the variability of HD-tDCS induced electric fields (EFs) and its impact on resting-state functional connectivity (rsFC) during different time windows. METHODS In this randomized, double-blind, and sham controlled study, seventy healthy males underwent 20 min of 1.5 mA HD-tDCS on the right inferior frontal gyrus (rIFG) while undergoing resting-state functional magnetic resonance imaging (rs-fMRI). Individual head models and EF simulations were created from anatomical images. The effects of HD-tDCS on rsFC were assessed using a seed-to-voxel analysis. A subgroup analysis explored the relationship between EF magnitude and rsFC during different stimulation time windows. RESULTS Results highlighted significant variability in HD-tDCS-induced EFs. Compared to the sham group, the active group showed increased rsFC between the rIFG and the left prefrontal cortex, during and after stimulation. During active stimulation, EF magnitude correlated positively with rsFC between the rIFG and the left hippocampus initially, and negatively during the subsequent period. CONCLUSION This study indicated an HD-tDCS induced increase of rsFC between left and right prefrontal areas. Furthermore, an interaction between the magnitude and the duration of HD-tDCS on rsFC was observed. Due to the high EF variability that was apparent, these findings highlight the need for individualized HD-tDCS protocols and the creation of head models to optimize effects and reduce response heterogeneity.
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Affiliation(s)
- Dario Müller
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany; JARA-BRAIN Institute Brain Structure-Function Relationships, Research Center Jülich and RWTH Aachen, Germany; Institute of Neuroscience and Medicine 10, Research Center Jülich, 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
| | - Benjamin Clemens
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Carmen Weidler
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany
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Chen L, Chen G, Gong X, Fang F. Integrating electric field modeling and pre-tDCS behavioral performance to predict the individual tDCS effect on visual crowding. J Neural Eng 2023; 20:056019. [PMID: 37750681 DOI: 10.1088/1741-2552/acfa8c] [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: 05/12/2023] [Accepted: 09/15/2023] [Indexed: 09/27/2023]
Abstract
Objective.Transcranial direct current stimulation (tDCS) has been broadly used to modulate brain activity with both bipolar and high-definition montages. However, tDCS effects can be highly variable. In this work, we investigated whether the variability in the tDCS effects could be predicted by integrating individualized electric field modeling and individual pre-tDCS behavioral performance.Approach.Here, we first compared the effects of bipolar tDCS and 4 × 1 high-definition tDCS (HD-tDCS) with respect to the alleviation of visual crowding, which is the inability to identify targets in the presence of nearby flankers and considered to be an essential bottleneck of object recognition and visual awareness. We instructed subjects to perform an orientation discrimination task with both isolated and crowded targets in the periphery and measured their orientation discrimination thresholds before and after receiving 20 min of bipolar tDCS, 4 × 1 HD-tDCS, or sham stimulation over the visual cortex. Individual anatomically realistic head models were constructed to simulate tDCS-induced electric field distributions and quantify tDCS focality. Finally, a multiple linear regression model that used pre-tDCS behavioral performance and tDCS focality as factors was used to predict post-tDCS behavioral performance.Main results.We found that HD-tDCS, but not bipolar tDCS, could significantly alleviate visual crowding. Moreover, the variability in the tDCS effect could be reliably predicted by subjects' pre-tDCS behavioral performance and tDCS focality. This prediction model also performed well when generalized to other two tDCS protocols with a different electrode size or a different stimulation intensity.Significance.Our study links the variability in the tDCS-induced electric field and the pre-tDCS behavioral performance in a visual crowding task to the variability in post-tDCS performance. It provides a new approach to predicting individual tDCS effects and highlights the importance of understanding the factors that determine tDCS effectiveness while developing more robust protocols.
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Affiliation(s)
- Luyao Chen
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, People's Republic of China
- Beijing Academy of Artificial Intelligence, Beijing 100084, People's Republic of China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, People's Republic of China
- Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, People's Republic of China
| | - Guanpeng Chen
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, People's Republic of China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, People's Republic of China
- Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, People's Republic of China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Xizi Gong
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, People's Republic of China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, People's Republic of China
- Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, People's Republic of China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Fang Fang
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, People's Republic of China
- Beijing Academy of Artificial Intelligence, Beijing 100084, People's Republic of China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, People's Republic of China
- Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, People's Republic of China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, People's Republic of China
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7
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Škarabot J, Ammann C, Balshaw TG, Divjak M, Urh F, Murks N, Foffani G, Holobar A. Decoding firings of a large population of human motor units from high-density surface electromyogram in response to transcranial magnetic stimulation. J Physiol 2023; 601:1719-1744. [PMID: 36946417 PMCID: PMC10952962 DOI: 10.1113/jp284043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 03/17/2023] [Indexed: 03/23/2023] Open
Abstract
We describe a novel application of methodology for high-density surface electromyography (HDsEMG) decomposition to identify motor unit (MU) firings in response to transcranial magnetic stimulation (TMS). The method is based on the MU filter estimation from HDsEMG decomposition with convolution kernel compensation during voluntary isometric contractions and its application to contractions elicited by TMS. First, we simulated synthetic HDsEMG signals during voluntary contractions followed by simulated motor evoked potentials (MEPs) recruiting an increasing proportion of the motor pool. The estimation of MU filters from voluntary contractions and their application to elicited contractions resulted in high (>90%) precision and sensitivity of MU firings during MEPs. Subsequently, we conducted three experiments in humans. From HDsEMG recordings in first dorsal interosseous and tibialis anterior muscles, we demonstrated an increase in the number of identified MUs during MEPs evoked with increasing stimulation intensity, low variability in the MU firing latency and a proportion of MEP energy accounted for by decomposition similar to voluntary contractions. A negative relationship between the MU recruitment threshold and the number of identified MU firings was exhibited during the MEP recruitment curve, suggesting orderly MU recruitment. During isometric dorsiflexion we also showed a negative association between voluntary MU firing rate and the number of firings of the identified MUs during MEPs, suggesting a decrease in the probability of MU firing during MEPs with increased background MU firing rate. We demonstrate accurate identification of a large population of MU firings in a broad recruitment range in response to TMS via non-invasive HDsEMG recordings. KEY POINTS: Transcranial magnetic stimulation (TMS) of the scalp produces multiple descending volleys, exciting motor pools in a diffuse manner. The characteristics of a motor pool response to TMS have been previously investigated with intramuscular electromyography (EMG), but this is limited in its capacity to detect many motor units (MUs) that constitute a motor evoked potential (MEP) in response to TMS. By simulating synthetic signals with known MU firing patterns, and recording high-density EMG signals from two human muscles, we show the feasibility of identifying firings of many MUs that comprise a MEP. We demonstrate the identification of firings of a large population of MUs in the broad recruitment range, up to maximal MEP amplitude, with fewer required stimuli compared to intramuscular EMG recordings. The methodology demonstrates an emerging possibility to study responses to TMS on a level of individual MUs in a non-invasive manner.
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Affiliation(s)
- Jakob Škarabot
- School of Sport, Exercise and Health SciencesLoughborough UniversityLoughboroughUK
| | - Claudia Ammann
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del SurHM HospitalesMadridSpain
- CIBERNEDInstituto de Salud Carlos IIIMadridSpain
| | - Thomas G. Balshaw
- School of Sport, Exercise and Health SciencesLoughborough UniversityLoughboroughUK
| | - Matjaž Divjak
- Systems Software Laboratory, Faculty of Electrical Engineering and Computer ScienceUniversity of MariborMariborSlovenia
| | - Filip Urh
- Systems Software Laboratory, Faculty of Electrical Engineering and Computer ScienceUniversity of MariborMariborSlovenia
| | - Nina Murks
- Systems Software Laboratory, Faculty of Electrical Engineering and Computer ScienceUniversity of MariborMariborSlovenia
| | - Guglielmo Foffani
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del SurHM HospitalesMadridSpain
- CIBERNEDInstituto de Salud Carlos IIIMadridSpain
- Hospital Nacional de ParapléjicosToledoSpain
| | - Aleš Holobar
- Systems Software Laboratory, Faculty of Electrical Engineering and Computer ScienceUniversity of MariborMariborSlovenia
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8
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Uehara S, Mawase F, Cherry-Allen KM, Runnalls K, Khan M, Celnik P. No Polarity-specific Modulation of Prefrontal-to-M1 Interhemispheric Inhibition by Transcranial Direct Current Stimulation Over the Lateral Prefrontal Cortex. Neuroscience 2023; 513:54-63. [PMID: 36708800 PMCID: PMC10086761 DOI: 10.1016/j.neuroscience.2023.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 01/08/2023] [Accepted: 01/20/2023] [Indexed: 01/27/2023]
Abstract
The lateral prefrontal cortex (PFC) plays a variety of crucial roles in higher-order cognitive functions. Previous works have attempted to modulate lateral PFC function by applying non-invasive transcranial direct current stimulation (tDCS) and demonstrated positive effects on performance of tasks involving cognitive processes. The neurophysiological underpinning of the stimulation effects, however, remain poorly understood. Here, we explored the neurophysiological after-effects of tDCS over the lateral PFC by assessing changes in the magnitude of interhemispheric inhibition from the lateral PFC to the contralateral primary motor cortex (PFC-M1 IHI). Using a dual-site transcranial magnetic stimulation paradigm, we assessed PFC-M1 IHI before and after the application of tDCS over the right lateral PFC. We conducted a double-blinded, crossover, and counterbalanced design where 15 healthy volunteers participated in three sessions during which they received either anodal, cathodal, and sham tDCS. In order to determine whether PFC-M1 IHI could be modulated at all, we completed the same assessment on a separate group of 15 participants as they performed visuo-motor reaction tasks that likely engage the lateral PFC. The results showed that tDCS over the right lateral PFC did not modulate the magnitude of PFC-M1 IHI, whereas connectivity changed when Go/NoGo decisions were implemented in reactions during the motor tasks. Although PFC-M1 IHI is sensitive enough to be modulated by behavioral manipulations, tDCS over the lateral PFC does not have substantial modulatory effects on PFC to M1 functional connectivity, or at least not to the degree that can be detected with this measure.
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Affiliation(s)
- Shintaro Uehara
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD, USA; School of Health Sciences, Fujita Health University, Aichi, Japan.
| | - Firas Mawase
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD, USA; Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Kendra M Cherry-Allen
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Keith Runnalls
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Maheen Khan
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Pablo Celnik
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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9
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Therrien-Blanchet JM, Ferland MC, Badri M, Rousseau MA, Merabtine A, Boucher E, Hofmann LH, Lepage JF, Théoret H. The neurophysiological aftereffects of brain stimulation in human primary motor cortex: a Sham-controlled comparison of three protocols. Cereb Cortex 2023:7030623. [PMID: 36749004 DOI: 10.1093/cercor/bhad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/14/2023] [Accepted: 01/15/2023] [Indexed: 02/08/2023] Open
Abstract
Paired associative stimulation (PAS), transcranial direct current stimulation (tDCS), and transcranial alternating current stimulation (tACS) are non-invasive brain stimulation methods that are used to modulate cortical excitability. Whether one technique is superior to the others in achieving this outcome and whether individuals that respond to one intervention are more likely to respond to another remains largely unknown. In the present study, the neurophysiological aftereffects of three excitatory neurostimulation protocols were measured with transcranial magnetic stimulation (TMS). Twenty minutes of PAS at an ISI of 25 ms, anodal tDCS, 20-Hz tACS, and Sham stimulation were administered to 31 healthy adults in a repeated measures design. Compared with Sham, none of the stimulation protocols significantly modulated corticospinal excitability (input/ouput curve and slope, TMS stimulator intensity required to elicit MEPs of 1-mV amplitude) or intracortical excitability (short- and long-interval intracortical inhibition, intracortical facilitation, cortical silent period). Sham-corrected responder analysis estimates showed that an average of 41 (PAS), 39 (tDCS), and 39% (tACS) of participants responded to the interventions with an increase in corticospinal excitability. The present data show that three stimulation protocols believed to increase cortical excitability are associated with highly heterogenous and variable aftereffects that may explain a lack of significant group effects.
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Affiliation(s)
| | | | - Meriem Badri
- Département de psychologie, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | | | - Amira Merabtine
- Département de psychologie, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Emelie Boucher
- Département de psychologie, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Lydia Helena Hofmann
- Department of Psychology and Neuroscience, Maastricht University, Maastricht 6229, The Netherlands
| | - Jean-François Lepage
- Département de Pédiatrie, Faculté de Médecine et des Sciences de la Santé de l'Université de Sherbrooke, Centre de Recherche du CHU Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Hugo Théoret
- Département de psychologie, Université de Montréal, Montréal, QC H3C 3J7, Canada
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10
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Left Prefrontal tDCS during Learning Does Not Enhance Subsequent Verbal Episodic Memory in Young Adults: Results from Two Double-Blind and Sham-Controlled Experiments. Brain Sci 2023; 13:brainsci13020241. [PMID: 36831783 PMCID: PMC9954521 DOI: 10.3390/brainsci13020241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/21/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
Recent studies suggest that transcranial direct current stimulation (tDCS) applied over the prefrontal cortex (PFaC) may enhance episodic memory ability. As such, there is ongoing interest in the therapeutic potential of this technique in age-related memory decline. At the same time, the findings are not yet conclusive regarding the magnitude of this effect, and assumptions regarding underlying brain mechanisms of stimulation-induced changes in behaviour are yet to be tested in detail. Here, we evaluated the effect of tDCS over left PFC on verbal episodic memory in young adults. Two separate randomized, double-blind, sham-controlled experiments were carried out using (1) incidental learning followed by a recognition test and (2) intentional learning followed by a free recall. In both studies, participants performed a learning task with active or sham tDCS during the encoding period, followed by retrieval tasks on the same day and the next day. The results suggest that, contrary to expectations, active tDCS did not enhance memory performance relative to sham tDCS. Possible reasons behind the lack of enhancement effects are discussed, including the possibility that memory enhancement effects of tDCS may be smaller than first thought. Scientific practices that could improve estimation accuracy in the field are also discussed.
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Han J, Choi KM, Yang C, Kim HS, Park SS, Lee SH. Treatment efficacy of tDCS and predictors of treatment response in patients with post-traumatic stress disorder. J Affect Disord 2022; 318:357-363. [PMID: 36055537 DOI: 10.1016/j.jad.2022.08.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/31/2022] [Accepted: 08/26/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND Although transcranial direct stimulation (tDCS) has been proposed as an alternative treatment option for various psychiatric disorders, there is inconsistent information regarding the treatment effects of tDCS for patients with post-traumatic stress disorder (PTSD). This study aimed to investigate the tDCS efficacy and identify predictors of treatment response to tDCS in patients with PTSD. METHOD Fifty-one patients received 10 sessions of tDCS involving the position of the anode over the F3 area and cathode over the F4 as a condition of 2.0 mA and 20 min duration. Digit span test and 10 questionnaires (Clinician-Administered PTSD Scale (CAPS), Cognitive Emotion Regulation Questionnaire (CERQ), Multidimensional Experiential Avoidance Questionnaire (MEAQ), etc.) were used to measure tDCS effects on PTSD symptoms and identify predictors of response to tDCS. RESULTS 1) 50.9 % of patients had a significant reduction in the frequency and severity of PTSD symptoms, 2) PTSD-related symptoms such as depression, anxiety, rumination, and quality of life were significantly improved, 3) baseline scores on rumination and digit span test significantly predicted treatment response to tDCS. LIMITATIONS This study was open design without a sham control group. Also, the patients' medications were not controlled. CONCLUSION This study highlighted the efficacy of frontal tDCS for the treatment of patients with PTSD and identified rumination and digit span as favorable predictive factors for the outcomes of tDCS.
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Affiliation(s)
- Jungwon Han
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea; Department of Psychology, Sogang University, Seoul, Republic of Korea
| | - Kang-Min Choi
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea; School of Electronic Engineering, Hanyang University, Seoul, Republic of Korea
| | - Chaeyeon Yang
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea; Department of Psychology, Sogang University, Seoul, Republic of Korea
| | - Hyang Sook Kim
- Department of Psychology, Sogang University, Seoul, Republic of Korea
| | | | - Seung-Hwan Lee
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea; Department of Psychiatry, Inje University, Ilsan-Paik Hospital, Goyang, Republic of Korea; Bwave Inc., Juhwa-ro, Goyang 10380, Republic of Korea..
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12
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de la Salle S, Shah U, Hyde M, Baysarowich R, Aidelbaum R, Choueiry J, Knott V. Synchronized Auditory Gamma Response to Frontal Transcranial Direct Current Stimulation (tDCS) and its Inter-Individual Variation in Healthy Humans. Clin EEG Neurosci 2022; 53:472-483. [PMID: 35491558 DOI: 10.1177/15500594221098285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In schizophrenia, a disorder associated with N-methyl-D-aspartate receptor (NMDAR) hypofunction, auditory cortical plasticity deficits have been indexed by the synchronized electroencephalographic (EEG) auditory steady-state gamma-band (40-Hz) response (ASSR) and the early auditory evoked gamma-band response (aeGBR), both considered to be target engagement biomarkers for NMDAR function, and potentially amenable to treatment by NMDAR modulators. As transcranial direct current stimulation (tDCS) is likely dependent on NMDAR neurotransmission, this preliminary study, conducted in 30 healthy volunteers, assessed the off-line effects of prefrontal anodal tDCS and sham (placebo) treatment on 40-Hz ASSR and aeGBR. Anodal tDCS failed to alter aeGBR but increased both 40-Hz ASSR power, as measured by event-related spectral perturbations (ERSP), and phase locking, as measured by inter-trial phase consistency (ITPC). Inter-individual differences in tDCS-induced increases in ERSP were negatively related to baseline ERSPs. These findings provide tentative support for further study of tDCS as a potential NMDAR neuromodulatory intervention for synchronized auditory gamma response deficits.
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Affiliation(s)
- Sara de la Salle
- 580059The Royal's Institute of Mental Health Research, Ottawa, ON, Canada
| | - Urusa Shah
- Neuroscience, 6339Carleton University, Ottawa, ON, Canada
| | - Molly Hyde
- Department of Cellular and Molecular Medicine, 6363University of Ottawa, Ottawa, ON, Canada
| | - Renee Baysarowich
- Department of Cellular and Molecular Medicine, 6363University of Ottawa, Ottawa, ON, Canada
| | - Robert Aidelbaum
- School of Psychology, 6339Carleton University, Ottawa, ON, Canada
| | - Joëlle Choueiry
- 580059The Royal's Institute of Mental Health Research, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, 6363University of Ottawa, Ottawa, ON, Canada
| | - Verner Knott
- 580059The Royal's Institute of Mental Health Research, Ottawa, ON, Canada.,Neuroscience, 6339Carleton University, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, 6363University of Ottawa, Ottawa, ON, Canada.,School of Psychology, 6339Carleton University, Ottawa, ON, Canada
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13
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Li Y, Li HP, Wu MX, Wang QY, Zeng X. Effects of transcranial direct current stimulation for post-stroke depression: A systematic review and meta-analysis. Clin Neurophysiol 2022; 142:1-10. [DOI: 10.1016/j.clinph.2022.07.369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 04/05/2022] [Accepted: 07/09/2022] [Indexed: 12/24/2022]
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14
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Muccio M, Walton Masters L, Pilloni G, He P, Krupp L, Datta A, Bikson M, Charvet L, Ge Y. Cerebral metabolic rate of oxygen (CMRO 2) changes measured with simultaneous tDCS-MRI in healthy adults. Brain Res 2022; 1796:148097. [PMID: 36150457 DOI: 10.1016/j.brainres.2022.148097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/06/2022] [Accepted: 09/16/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is a safe and well-tolerated noninvasive technique used for cortical excitability modulation. tDCS has been extensively investigated for its clinical applications; however further understanding of its underlying in-vivo physiological mechanisms remains a fundamental focus of current research. OBJECTIVES We investigated the simultaneous effects of tDCS on cerebral blood flow (CBF), venous blood oxygenation (Yv) and cerebral metabolic rate of oxygen (CMRO2) using simultaneous MRI in healthy adults to provide a reference frame for its neurobiological mechanisms. METHODS Twenty-three healthy participants (age = 35.6 ± 15.0 years old, 10 males) completed a simultaneous tDCS-MRI session in a 3 T scanner fitted with a 64-channels head coil. A MR-compatible tDCS device was used to acquire CBF, Yv and CMRO2 at three time points: pre-, during- and post- 15 minutes of 2.0 mA tDCS on left anodal dorsolateral prefrontal cortex. RESULTS During tDCS, CBF significantly increased (57.10 ± 8.33 mL/100g/min) from baseline (53.67 ± 7.75 mL/100g/min; p < 0.0001) and remained elevated in post-tDCS (56.79 ± 8.70 mL/100g/min). Venous blood oxygenation levels measured in pre-tDCS (60.71 ± 4.12 %) did not significantly change across the three timepoints. The resulting CMRO2 significantly increased by 5.9 % during-tDCS (175.68 ± 30.78 µmol/100g/min) compared to pre-tDCS (165.84 ± 25.32 µmol/100g/min; p = 0.0015), maintaining increased levels in post-tDCS (176.86 ± 28.58 µmol/100g/min). CONCLUSIONS tDCS has immediate effects on neuronal excitability, as measured by increased cerebral blood supply and oxygen consumption supporting increased neuronal firing. These findings provide a standard range of CBF and CMRO2 changes due to tDCS in healthy adults that may be incorporated in clinical studies to evaluate its therapeutic potential.
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Affiliation(s)
- Marco Muccio
- Department of Radiology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Lillian Walton Masters
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Giuseppina Pilloni
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Peidong He
- Department of Radiology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Lauren Krupp
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Abhishek Datta
- Research and Development, Soterix Medical, Inc, Woodbridge, NJ, United States
| | - Marom Bikson
- Department of Biomedical Engineering, City College of New York, New York City, NY, United States
| | - Leigh Charvet
- Department of Neurology, NYU Grossman School of Medicine, New York City, NY, United States
| | - Yulin Ge
- Department of Radiology, NYU Grossman School of Medicine, New York City, NY, United States.
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15
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Kunaratnam N, Saumer TM, Kuan G, Holmes Z, Swarbrick D, Kiss A, Mochizuki G, Chen JL. Transcranial direct current stimulation leads to faster acquisition of motor skills, but effects are not maintained at retention. PLoS One 2022; 17:e0269851. [PMID: 36099260 PMCID: PMC9469971 DOI: 10.1371/journal.pone.0269851] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/29/2022] [Indexed: 11/28/2022] Open
Abstract
Practice is required to improve one’s shooting technique in basketball or to play a musical instrument well. Learning these motor skills may be further enhanced by transcranial direct current stimulation (tDCS). We aimed to investigate whether tDCS leads to faster attainment of a motor skill, and to confirm prior work showing it improves skill acquisition and retention performance. Fifty-two participants were tested; half received tDCS with the anode on primary motor cortex and cathode on the contralateral forehead while concurrently practicing a sequential visuomotor isometric pinch force task on Day 1, while the other half received sham tDCS during practice. On Day 2, retention of the skill was tested. Results from a Kaplan-Meier survival analysis showed that participants in the anodal group attained a pre-defined target level of skill faster than participants in the sham group (χ2 = 9.117, p = 0.003). Results from a nonparametric rank-based regression analysis showed that the rate of improvement was greater in the anodal versus sham group during skill acquisition (F(1,249) = 5.90, p = 0.016), but there was no main effect of group or time. There was no main effect of group or time, or group by time interaction when comparing performance at the end of acquisition to retention. These findings suggest anodal tDCS improves performance more quickly during skill acquisition but does not have additional benefits on motor learning after a period of rest.
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Affiliation(s)
- Nirsan Kunaratnam
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Tyler M. Saumer
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Giovanna Kuan
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Zacharie Holmes
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Dana Swarbrick
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Alex Kiss
- Evaluative Clinical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - George Mochizuki
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Joyce L. Chen
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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16
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Kashyap R, Bhattacharjee S, Bharath RD, Venkatasubramanian G, Udupa K, Bashir S, Oishi K, Desmond JE, Chen SHA, Guan C. Variation of cerebrospinal fluid in specific regions regulates focality in transcranial direct current stimulation. Front Hum Neurosci 2022; 16:952602. [PMID: 36118967 PMCID: PMC9479459 DOI: 10.3389/fnhum.2022.952602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundConventionally, transcranial direct current stimulation (tDCS) aims to focalize the current reaching the target region-of-interest (ROI). The focality can be quantified by the dose-target-determination-index (DTDI). Despite having a uniform tDCS setup, some individuals receive focal stimulation (high DTDI) while others show reduced focality (“non-focal”). The volume of cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) underlying each ROI govern the tDCS current distribution inside the brain, thereby regulating focality.AimTo determine the regional volume parameters that differentiate the focal and non-focal groups.MethodsT1-weighted images of the brain from 300 age-sex matched adults were divided into three equal groups- (a) Young (20 ≤ × < 40 years), (b) Middle (40 ≤ × < 60 years), and (c) Older (60 ≤ × < 80 years). For each group, inter and intra-hemispheric montages with electrodes at (1) F3 and right supraorbital region (F3-RSO), and (2) CP5 and Cz (CP5-Cz) were simulated, targeting the left- Dorsolateral Prefrontal Cortex (DLPFC) and -Inferior Parietal Lobule (IPL), respectively. Both montages were simulated for two current doses (1 and 2 mA). For each individual head simulated for a tDCS configuration (montage and dose), the current density at each region-of-interest (ROI) and their DTDI were calculated. The individuals were categorized into two groups- (1) Focal (DTDI ≥ 0.75), and (2) Non-focal (DTDI < 0.75). The regional volume of CSF, GM, and WM of all the ROIs was determined. For each tDCS configuration and ROI, three 3-way analysis of variance was performed considering- (i) GM, (ii) WM, and (iii) CSF as the dependent variable (DV). The age group, sex, and focality group were the between-subject factors. For a given ROI, if any of the 3 DV’s showed a significant main effect or interaction involving the focality group, then that ROI was classified as a “focal ROI.”ResultsRegional CSF was the principal determinant of focality. For interhemispheric F3-RSO montage, interaction effect (p < 0.05) of age and focality was observed at Left Caudate Nucleus, with the focal group exhibiting higher CSF volume. The CSF volume of focal ROI correlated positively (r ∼ 0.16, p < 0.05) with the current density at the target ROI (DLPFC). For intrahemispheric CP5-Cz montage, a significant (p < 0.05) main effect was observed at the left pre- and post-central gyrus, with the focal group showing lower CSF volume. The CSF volume correlated negatively (r ∼ –0.16, p < 0.05) with current density at left IPL. The results were consistent for both current doses.ConclusionThe CSF channels the flow of tDCS current between electrodes with focal ROIs acting like reservoirs of current. The position of focal ROI in the channel determines the stimulation intensity at the target ROI. For focal stimulation in interhemispheric F3-RSO, the proximity of focal ROI reserves the current density at the target ROI (DLPFC). In contrast, for intrahemispheric montage (CP5-Cz), the far-end location of focal ROI reduces the current density at the target (IPL).
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Affiliation(s)
- Rajan Kashyap
- Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, India
- School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore
- *Correspondence: Rajan Kashyap,
| | - Sagarika Bhattacharjee
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
- Psychology, School of Social Sciences (SSS), Nanyang Technological University, Singapore, Singapore
| | - Rose Dawn Bharath
- Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, India
| | - Ganesan Venkatasubramanian
- InSTAR Program, Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, India
| | - Kaviraja Udupa
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Shahid Bashir
- Neuroscience Center, King Fahad Specialist Hospital Dammam, Dammam, Saudi Arabia
| | - Kenichi Oishi
- The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - John E. Desmond
- The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - S. H. Annabel Chen
- Psychology, School of Social Sciences (SSS), Nanyang Technological University, Singapore, Singapore
- Centre for Research and Development in Learning (CRADLE), Nanyang Technological University, Singapore, Singapore
- Lee Kong Chian School of Medicine (LKC Medicine), Nanyang Technological University, Singapore, Singapore
- National Institute of Education, Nanyang Technological University, Singapore, Singapore
| | - Cuntai Guan
- School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore
- Cuntai Guan,
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17
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Swissa Y, Hacohen S, Friedman J, Frenkel-Toledo S. Sensorimotor performance after high-definition transcranial direct current stimulation over the primary somatosensory or motor cortices in men versus women. Sci Rep 2022; 12:11117. [PMID: 35778465 PMCID: PMC9249866 DOI: 10.1038/s41598-022-15226-2] [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: 02/01/2022] [Accepted: 06/21/2022] [Indexed: 12/03/2022] Open
Abstract
The primary somatosensory (S1) cortex is a central structure in motor performance. However, transcranial direct current stimulation (tDCS) research aimed at improving motor performance usually targets the primary motor cortex (M1). Recently, sex was found to mediate tDCS response. Thus, we investigated whether tDCS with an anodal electrode placed over S1 improves motor performance and sensation perception in men versus women. Forty-five participants randomly received 15-min high-definition tDCS (HD-tDCS) at 1 mA to S1, M1, or sham stimulation. Reaching performance was tested before and immediately following stimulation. Two-point orientation discrimination (TPOD) of fingers and proprioception of a reaching movement were also tested. Although motor performance did not differ between groups, reaching reaction time improved in the M1 group men. Reaching movement time and endpoint error improved in women and men, respectively. Correct trials percentage for TPOD task was higher in the S1 compared to the M1 group in the posttest and improved only in the S1 group. Reaching movement time for the proprioception task improved, overall, and endpoint error did not change. Despite the reciprocal connections between S1 and M1, effects of active tDCS over S1 and M1 may specifically influence sensation perception and motor performance, respectively. Also, sex may mediate effects of HD-tDCS on motor performance.
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Affiliation(s)
- Yochai Swissa
- Department of Physical Therapy, Faculty of Health Sciences, Ariel University, Ariel, Israel
| | - Shlomi Hacohen
- Department of Mechanical Engineering, Ariel University, Ariel, Israel
| | - Jason Friedman
- Department of Physical Therapy, Stanley Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Silvi Frenkel-Toledo
- Department of Physical Therapy, Faculty of Health Sciences, Ariel University, Ariel, Israel. .,Department of Neurological Rehabilitation, Loewenstein Rehabilitation Medical Center, Ra'anana, Israel.
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18
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Kalloch B, Weise K, Lampe L, Bazin PL, Villringer A, Hlawitschka M, Sehm B. The influence of white matter lesions on the electric field in transcranial electric stimulation. Neuroimage Clin 2022; 35:103071. [PMID: 35671557 PMCID: PMC9168230 DOI: 10.1016/j.nicl.2022.103071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/04/2022] [Accepted: 05/30/2022] [Indexed: 11/25/2022]
Abstract
Sensitivity analysis allows the simulation of tDCS with uncertain conductivities. White matter lesions (WML) have no global influence on the electric field in tDCS. In subjects with a high lesion load, a local influence can be observed. In low to medium lesion load subjects, explicit modeling of WML is not required.
Background Transcranial direct current stimulation (tDCS) is a promising tool to enhance therapeutic efforts, for instance, after a stroke. The achieved stimulation effects exhibit high inter-subject variability, primarily driven by perturbations of the induced electric field (EF). Differences are further elevated in the aging brain due to anatomical changes such as atrophy or lesions. Informing tDCS protocols by computer-based, individualized EF simulations is a suggested measure to mitigate this variability. Objective While brain anatomy in general and specifically atrophy as well as stroke lesions are deemed influential on the EF in simulation studies, the influence of the uncertainty in the change of the electrical properties of the white matter due to white matter lesions (WMLs) has not been quantified yet. Methods A group simulation study with 88 subjects assigned into four groups of increasing lesion load was conducted. Due to the lack of information about the electrical conductivity of WMLs, an uncertainty analysis was employed to quantify the variability in the simulation when choosing an arbitrary conductivity value for the lesioned tissue. Results The contribution of WMLs to the EF variance was on average only one tenth to one thousandth of the contribution of the other modeled tissues. While the contribution of the WMLs significantly increased (p≪.01) in subjects exhibiting a high lesion load compared to low lesion load subjects, typically by a factor of 10 and above, the total variance of the EF didnot change with the lesion load. Conclusion Our results suggest that WMLs do not perturb the EF globally and can thus be omitted when modeling subjects with low to medium lesion load. However, for high lesion load subjects, the omission of WMLs may yield less robust local EF estimations in the vicinity of the lesioned tissue. Our results contribute to the efforts of accurate modeling of tDCS for treatment planning.
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Affiliation(s)
- Benjamin Kalloch
- Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Leipzig, Germany; Leipzig University of Applied Science, Faculty of Computer Science and Media, Leipzig, Germany; Max Planck Institute for Human Cognitive and Brain Sciences, Methods and Development Group "Brain Networks", Leipzig, Germany; Technische Universität Ilmenau, Instiute of Biomedical Engineering and Informatics, Ilmenau, Germany.
| | - Konstantin Weise
- Max Planck Institute for Human Cognitive and Brain Sciences, Methods and Development Group "Brain Networks", Leipzig, Germany; Technische Universität Ilmenau, Advanced Electromagnetics Group, Ilmenau, Germany
| | - Leonie Lampe
- Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Leipzig, Germany
| | - Pierre-Louis Bazin
- Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Leipzig, Germany; University of Amsterdam, Faculty of Social and Behavioural Sciences, Amsterdam, The Netherlands
| | - Arno Villringer
- Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Leipzig, Germany
| | - Mario Hlawitschka
- Leipzig University of Applied Science, Faculty of Computer Science and Media, Leipzig, Germany
| | - Bernhard Sehm
- Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Leipzig, Germany; Department of Neurology, Martin Luther University of Halle-Wittenberg, Germany
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19
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Griffin L, Kamarunas E, Kuo C, O'Donoghue C. Comparing amplitudes of transcranial direct current stimulation (tDCS) to the sensorimotor cortex during swallowing. Exp Brain Res 2022; 240:1811-1822. [PMID: 35551431 DOI: 10.1007/s00221-022-06381-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/25/2022] [Indexed: 11/04/2022]
Abstract
PURPOSE Transcranial direct current stimulation (tDCS) can alter cortical excitability, making it a useful tool for promoting neuroplasticity in dysphagia rehabilitation. Clinical trials show functional improvements in swallowing following anodal tDCS despite varying dosing parameters and outcomes. The aim of the current study was to determine the most effective amplitude criterion (e.g., 0 mA [sham/control], 1 mA, 2 mA) of anodal tDCS for upregulating the swallowing sensorimotor cortex. METHOD As a novel paradigm, tDCS, functional near-infrared spectroscopy (fNIRS), and surface electromyography (sEMG) were simultaneously administered while participants completed a swallowing task. This allowed for measurement of the cortical hemodynamic response and submental muscle contraction before, during, and after tDCS. At the conclusion of the study, participants were asked to rate their level of discomfort associated with tDCS using a visual analog scale. RESULTS There was no significant difference in the hemodynamic response by time or amplitude. However, post-hoc analyses indicated that in the post-stimulation period, changes to the hemodynamic response in the left (stimulated) hemisphere were significantly different for the groups receiving 1 mA and 2 mA of tDCS compared to baseline. Participants receiving 1 mA of tDCS demonstrated reduced hemodynamic response. There was no significant difference in submental muscle contraction during or after tDCS regardless of amplitude. Anodal tDCS was well tolerated in healthy adults with no difference among participant discomfort scores across tDCS amplitude. CONCLUSIONS During a swallowing task, healthy volunteers receiving 1 mA of anodal tDCS demonstrated a suppressed hemodynamic response during and after stimulation whereas those receiving 2 mA of anodal tDCS had an increase in the hemodynamic response. tDCS remains a promising tool in dysphagia rehabilitation, but dosing parameters require further clarification.
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Affiliation(s)
- Lindsay Griffin
- School of Communication, Communication Sciences and Disorders, Emerson College, 120 Boylston St., Boston, MA, 02116, USA. .,College of Health and Behavioral Studies, Communication Sciences and Disorders, James Madison University, 235 Martin Luther King Jr. Way, Harrisonburg, VA, 22807, USA.
| | - Erin Kamarunas
- College of Health and Behavioral Studies, Communication Sciences and Disorders, James Madison University, 235 Martin Luther King Jr. Way, Harrisonburg, VA, 22807, USA
| | - Christina Kuo
- College of Health and Behavioral Studies, Communication Sciences and Disorders, James Madison University, 235 Martin Luther King Jr. Way, Harrisonburg, VA, 22807, USA
| | - Cynthia O'Donoghue
- College of Health and Behavioral Studies, Communication Sciences and Disorders, James Madison University, 235 Martin Luther King Jr. Way, Harrisonburg, VA, 22807, USA
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20
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Inter-Individual Variability in tDCS Effects: A Narrative Review on the Contribution of Stable, Variable, and Contextual Factors. Brain Sci 2022; 12:brainsci12050522. [PMID: 35624908 PMCID: PMC9139102 DOI: 10.3390/brainsci12050522] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/08/2022] [Accepted: 04/14/2022] [Indexed: 01/27/2023] Open
Abstract
Due to its safety, portability, and cheapness, transcranial direct current stimulation (tDCS) use largely increased in research and clinical settings. Despite tDCS’s wide application, previous works pointed out inconsistent and low replicable results, sometimes leading to extreme conclusions about tDCS’s ineffectiveness in modulating behavioral performance across cognitive domains. Traditionally, this variability has been linked to significant differences in the stimulation protocols across studies, including stimulation parameters, target regions, and electrodes montage. Here, we reviewed and discussed evidence of heterogeneity emerging at the intra-study level, namely inter-individual differences that may influence the response to tDCS within each study. This source of variability has been largely neglected by literature, being results mainly analyzed at the group level. Previous research, however, highlighted that only a half—or less—of studies’ participants could be classified as responders, being affected by tDCS in the expected direction. Stable and variable inter-individual differences, such as morphological and genetic features vs. hormonal/exogenous substance consumption, partially account for this heterogeneity. Moreover, variability comes from experiments’ contextual elements, such as participants’ engagement/baseline capacity and individual task difficulty. We concluded that increasing knowledge on inter-dividual differences rather than undermining tDCS effectiveness could enhance protocols’ efficiency and reproducibility.
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Konicar L, Prillinger K, Klöbl M, Lanzenberger R, Antal A, Plener PL. Brain Stimulation for Emotion Regulation in Adolescents With Psychiatric Disorders: Study Protocol for a Clinical-Transdiagnostical, Randomized, Triple-Blinded and Sham-Controlled Neurotherapeutic Trial. Front Psychiatry 2022; 13:840836. [PMID: 35546931 PMCID: PMC9082670 DOI: 10.3389/fpsyt.2022.840836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Anxiety, conduct and depressive disorders represent three highly prevalent psychiatric conditions in adolescents. A shared underpinning of these disorders is a shortcoming in emotion regulation, connected to the functioning of the ventromedial prefrontal cortex. Thus, an intervention able to target the suggested neural correlate seems to be highly desirable, aiming to hinder a maladaptive development of emotion regulation abilities and chronification of associated psychiatric disorders. As transcranial direct current stimulation (tDCS) was repeatedly demonstrated as a safe and non-invasive method to modulate specific brain activity, research is in demand to evaluate neurotherapeutic applications in adolescents with psychiatric disorders. METHOD This transdiagnostic, randomized, triple-blind and sham-controlled clinical neurostimulation trial primary aims to investigate if emotion regulation abilities are increased after tDCS in adolescents with psychiatric disorders. Secondly, disorder-specific changes in the anxiety, depression or conduct disorder will be investigated, as well as changes in quality of life, and cognitive and emotional functioning after tDCS intervention. We will include 108 adolescents with psychiatric disorders, displaying a substantial deficit in emotion regulation. Of these, one third each has to be primarily diagnosed with a depressive, anxiety or conduct disorder, respectively. Participants will be randomized to the experimental group (n = 54) receiving real anodal tDCS, or to the control group (n = 54) receiving sham tDCS. Brain stimulation will be applied for 20 min on five consecutive days twice targeting the ventromedial prefrontal cortex (vmPFC). Changes in emotion regulation, together with changes in disorder-specific clinical symptoms will be recorded by multi-informant psychological ratings. To inspect changes in behavior and gaze, computerized tasks and an eye tracker system will be used. Changes in brain responses to emotional and cognitive stimuli will be examined with three functional magnetic resonance imaging (fMRI) paradigms. In addition, a resting state MRI will be acquired to investigate possible changes in brain connectivity. DISCUSSION By investigating "emotion regulation" as transdiagnostic treatment target, this project is oriented toward the Research Domain Criteria framework with a dimensional view on mental illness. The study aims at investigating the potential of tDCS as non-invasive intervention for depressive, anxiety and conduct disorders in adolescents and broadening the scientific foundation for its clinical application. CLINICAL TRIAL REGISTRATION The study is ongoing and has been registered in the German Registry of Clinical Trials (DRKS-ID: DRKS00025601X) on the 28.06.2021.
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Affiliation(s)
- Lilian Konicar
- Department of Child and Adolescent Psychiatry, Medical University of Vienna, Vienna, Austria
| | - Karin Prillinger
- Department of Child and Adolescent Psychiatry, Medical University of Vienna, Vienna, Austria
| | - Manfred Klöbl
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Andrea Antal
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Paul L Plener
- Department of Child and Adolescent Psychiatry, Medical University of Vienna, Vienna, Austria.,Department of Child and Adolescents Psychiatry and Psychotherapy, Ulm University, Ulm, Germany
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22
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Focality-Oriented Selection of Current Dose for Transcranial Direct Current Stimulation. J Pers Med 2021; 11:jpm11090940. [PMID: 34575717 PMCID: PMC8466113 DOI: 10.3390/jpm11090940] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/18/2021] [Accepted: 09/18/2021] [Indexed: 11/30/2022] Open
Abstract
Background: In transcranial direct current stimulation (tDCS), the injected current becomes distributed across the brain areas. The objective is to stimulate the target region of interest (ROI) while minimizing the current in non-target ROIs (the 'focality' of tDCS). For this purpose, determining the appropriate current dose for an individual is difficult. Aim: To introduce a dose-target determination index (DTDI) to quantify the focality of tDCS and examine the dose-focality relationship in three different populations. Method: Here, we extended our previous toolbox i-SATA to the MNI reference space. After a tDCS montage is simulated for a current dose, the i-SATA(MNI) computes the average (over voxels) current density for every region in the brain. DTDI is the ratio of the average current density at the target ROI to the ROI with a maximum value (the peak region). Ideally, target ROI should be the peak region, so DTDI shall range from 0 to 1. The higher the value, the better the dose. We estimated the variation of DTDI within and across individuals using T1-weighted brain images of 45 males and females distributed equally across three age groups: (a) young adults (20 ≤ x ˂ 40 years), (b) mid adults (40 ≤ x ˂ 60 years), and (c) older adults (60 ≤ x ˂ 80 years). DTDI's were evaluated for the frontal montage with electrodes at F3 and the right supraorbital for three current doses of 1 mA, 2 mA, and 3 mA, with the target ROI at the left middle frontal gyrus. Result: As the dose is incremented, DTDI may show (a) increase, (b) decrease, and (c) no change across the individuals depending on the relationship (nonlinear or linear) between the injected tDCS current and the distribution of current density in the target ROI. The nonlinearity is predominant in older adults with a decrease in focality. The decline is stronger in males. Higher current dose at older age can enhance the focality of stimulation. Conclusion: DTDI provides information on which tDCS current dose will optimize the focality of stimulation. The recommended DTDI dose should be prioritized based on the age (>40 years) and sex (especially for males) of an individual. The toolbox i-SATA(MNI) is freely available.
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23
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Lee JH, Lee TL, Kang N. Transcranial direct current stimulation decreased cognition-related reaction time in older adults: A systematic review and meta-analysis. Ageing Res Rev 2021; 70:101377. [PMID: 34089900 DOI: 10.1016/j.arr.2021.101377] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/18/2021] [Accepted: 05/31/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND This systematic review and meta-analysis investigated the effects of transcranial direct current stimulation (tDCS) on the cognitive functions of healthy older adults by focusing on the changes in reaction time during cognitive tasks. METHOD A total of 31 studies qualified for this meta-analysis, and we acquired 36 comparisons from the included studies for data synthesis. The individual effect sizes were calculated by comparing the altered reaction time during the performance of a specific cognitive task between the active tDCS and sham groups. In two moderator variable analyses, we examined the potentially different effects of the tDCS protocols on the cognition-related reaction time based on the tDCS protocol used (i.e., online vs. offline tDCS) and the five cognitive domains: (a) perceptual-motor function, (b) learning and memory, (c) executive function / complex attention, (d) language, and (e) social cognition. Meta-regression analyses were conducted to estimate the relationship between demographic and tDCS parameter characteristics and the changes in reaction time. RESULTS The random-effects model meta-analysis revealed significant small effects of tDCS on cognition-related reaction time. Specifically, providing online tDCS significantly reduced the reaction time, and these patterns were observed during learning and memory and executive function / complex attention tasks. However, applying offline tDCS failed to find any significant reduction of reaction time across various cognitive tasks. The meta-regression analysis revealed that the effects of tDCS on the reaction time during the performance of cognitive tasks increased for the older people. CONCLUSIONS These findings suggest that providing online tDCS may effectively improve the ageing-induced reaction time related to specific cognitive functions of elderly people.
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24
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Lerner O, Friedman J, Frenkel-Toledo S. The effect of high-definition transcranial direct current stimulation intensity on motor performance in healthy adults: a randomized controlled trial. J Neuroeng Rehabil 2021; 18:103. [PMID: 34174914 PMCID: PMC8236155 DOI: 10.1186/s12984-021-00899-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/14/2021] [Indexed: 11/22/2022] Open
Abstract
Background The results of transcranial direct current stimulation (tDCS) studies that seek to improve motor performance for people with neurological disorders, by targeting the primary motor cortex, have been inconsistent. One possible reason, among others, for this inconsistency, is that very little is known about the optimal protocols for enhancing motor performance in healthy individuals. The best way to optimize stimulation protocols for enhancing tDCS effects on motor performance by means of current intensity modulation has not yet been determined. We aimed to determine the effect of current intensity on motor performance using–for the first time–a montage optimized for maximal focal stimulation via anodal high-definition tDCS (HD-tDCS) on the right primary motor cortex in healthy subjects. Methods Sixty participants randomly received 20-min HD-tDCS at 1.5, 2 mA, or sham stimulation. Participants’ reaching performance with the left hand on a tablet was tested before, during, and immediately following stimulation, and retested after 24 h. Results In the current montage of HD-tDCS, movement time did not differ between groups in each timepoint. However, only after HD-tDCS at 1.5 mA did movement time improve at posttest as compared to pretest. This reduction in movement time from pretest to posttest was significantly greater compared to HD-tDCS 2 mA. Following HD-tDCS at 1.5 mA and sham HD-tDCS, but not 2 mA, movement time improved at retest compared to pretest, and at posttest and retest compared to the movement time during stimulation. In HD-tDCS at 2 mA, the negligible reduction in movement time from the course of stimulation to posttest was significantly lower compared to sham HD-tDCS. Across all groups, reaction time improved in retest compared to pretest and to the reaction time during stimulation, and did not differ between groups in each timepoint. Conclusions It appears that 2 mA in this particular experimental setup inhibited the learning effects. These results suggest that excitatory effects induced by anodal stimulation do not hold for every stimulation intensity, information that should be taken into consideration when translating tDCS use from the realm of research into more optimal neurorehabilitation. Trial registration: Clinical Trials Gov, NCT04577768. Registered 6 October 2019 -Retrospectively registered, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S000A9B3&selectaction=Edit&uid=U0005AKF&ts=8&cx=buucf0. Supplementary Information The online version contains supplementary material available at 10.1186/s12984-021-00899-z.
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Affiliation(s)
- Ohad Lerner
- Department of Physical Therapy, Faculty of Health Sciences, Ariel University, Ariel, Israel
| | - Jason Friedman
- Department of Physical Therapy, Stanley Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Silvi Frenkel-Toledo
- Department of Physical Therapy, Faculty of Health Sciences, Ariel University, Ariel, Israel. .,Department of Neurological Rehabilitation, Loewenstein Hospital, Raanana, Israel.
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25
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fMRI and transcranial electrical stimulation (tES): A systematic review of parameter space and outcomes. Prog Neuropsychopharmacol Biol Psychiatry 2021; 107:110149. [PMID: 33096158 DOI: 10.1016/j.pnpbp.2020.110149] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 08/12/2020] [Accepted: 10/17/2020] [Indexed: 12/12/2022]
Abstract
The combination of non-invasive brain stimulation interventions with human brain mapping methods have supported research beyond correlational associations between brain activity and behavior. Functional MRI (fMRI) partnered with transcranial electrical stimulation (tES) methods, i.e., transcranial direct current (tDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation, explore the neuromodulatory effects of tES in the targeted brain regions and their interconnected networks and provide opportunities for individualized interventions. Advances in the field of tES-fMRI can be hampered by the methodological variability between studies that confounds comparability/replicability. In order to explore variability in the tES-fMRI methodological parameter space (MPS), we conducted a systematic review of 222 tES-fMRI experiments (181 tDCS, 39 tACS and 2 tRNS) published before February 1, 2019, and suggested a framework to systematically report main elements of MPS across studies. Publications dedicated to tRNS-fMRI were not considered in this systematic review. We have organized main findings in terms of fMRI modulation by tES. tES modulates activation and connectivity beyond the stimulated areas particularly with prefrontal stimulation. There were no two studies with the same MPS to replicate findings. We discuss how to harmonize the MPS to promote replication in future studies.
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26
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Prefrontal high definition cathodal tDCS modulates executive functions only when coupled with moderate aerobic exercise in healthy persons. Sci Rep 2021; 11:8457. [PMID: 33875729 PMCID: PMC8055664 DOI: 10.1038/s41598-021-87914-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/05/2021] [Indexed: 02/02/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a promising tool to enhance cognitive performance. However, its effectiveness has not yet been unequivocally shown. Thus, here we tested whether coupling tDCS with a bout of aerobic exercise (AE) is more effective in modulating cognitive functions than tDCS or AE alone. One hundred twenty-two healthy participants were assigned to five randomized controlled crossover experiments. Two multimodal target experiments (EXP-4: anodal vs. sham tDCS during AE; EXP-5: cathodal vs. sham tDCS during AE) investigated whether anodal (a-tDCS) or cathodal tDCS (c-tDCS) applied during AE over the left dorsolateral prefrontal cortex (left DLPFC) affects executive functioning (inhibition ability). In three unimodal control experiments, the participants were either stimulated (EXP-1: anodal vs. sham tDCS, EXP-2: cathodal vs. sham tDCS) or did AE (EXP-3: AE vs. active control). Participants performed an Eriksen flanker task during ergometer cycling at moderate intensity (in EXP. 3-5). Only c-tDCS during AE had a significant adverse effect on the inhibition task, with decreased accuracy. This outcome provides preliminary evidence that c-tDCS during AE over the left DLPFC might effectively modulate inhibition performance compared to c-tDCS alone. However, more systematic research is needed in the future.
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27
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Chen JL, Schipani A, Schuch CP, Lam H, Swardfager W, Thiel A, Edwards JD. Does Cathodal vs. Sham Transcranial Direct Current Stimulation Over Contralesional Motor Cortex Enhance Upper Limb Motor Recovery Post-stroke? A Systematic Review and Meta-analysis. Front Neurol 2021; 12:626021. [PMID: 33935936 PMCID: PMC8083132 DOI: 10.3389/fneur.2021.626021] [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: 11/04/2020] [Accepted: 03/03/2021] [Indexed: 11/17/2022] Open
Abstract
Background: During recovery from stroke, the contralesional motor cortex (M1) may undergo maladaptive changes that contribute to impaired interhemispheric inhibition (IHI). Transcranial direct current stimulation (tDCS) with the cathode over contralesional M1 may inhibit this maladaptive plasticity, normalize IHI, and enhance motor recovery. Objective: The objective of this systematic review and meta-analysis was to evaluate available evidence to determine whether cathodal tDCS on contralesional M1 enhances motor re-learning or recovery post-stroke more than sham tDCS. Methods: We searched OVID Medline, Embase, and the Cochrane Central Register of Controlled Trials for participants with stroke (>1 week post-onset) with motor impairment and who received cathodal or sham tDCS to contralesional M1 for one or more sessions. The outcomes included a change in any clinically validated assessment of physical function, activity, or participation, or a change in a movement performance variable (e.g., time, accuracy). A meta-analysis was performed by pooling five randomized controlled trials (RCTs) and comparing the change in Fugl–Meyer upper extremity scores between cathodal and sham tDCS groups. Results: Eleven studies met the inclusion criteria. Qualitatively, four out of five cross-over design studies and three out of six RCTs reported a significant effect of cathodal vs. sham tDCS. In the quantitative synthesis, cathodal tDCS (n = 65) did not significantly reduce motor impairment compared to sham tDCS (n = 67; standardized mean difference = 0.33, z = 1.79, p = 0.07) with a little observed heterogeneity (I2 = 5%). Conclusions: The effects of cathodal tDCS to contralesional M1 on motor recovery are small and consistent. There may be sub-populations that may respond to this approach; however, further research with larger cohorts is required.
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Affiliation(s)
- Joyce L Chen
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, ON, Canada.,Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada.,Rehabilitation Sciences Institute, University of Toronto, Toronto, ON, Canada
| | - Ashley Schipani
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, ON, Canada
| | | | - Henry Lam
- Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Walter Swardfager
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, ON, Canada.,Department of Pharmacology, University of Toronto, Toronto, ON, Canada
| | - Alexander Thiel
- Lady Davis Institute, Jewish General Hospital, Montreal, QC, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Jodi D Edwards
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, ON, Canada
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28
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Karabanov AN, Shindo K, Shindo Y, Raffin E, Siebner HR. Multimodal Assessment of Precentral Anodal TDCS: Individual Rise in Supplementary Motor Activity Scales With Increase in Corticospinal Excitability. Front Hum Neurosci 2021; 15:639274. [PMID: 33762917 PMCID: PMC7982814 DOI: 10.3389/fnhum.2021.639274] [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: 12/08/2020] [Accepted: 02/01/2021] [Indexed: 11/29/2022] Open
Abstract
Background Transcranial direct current stimulation (TDCS) targeting the primary motor hand area (M1-HAND) may induce lasting shifts in corticospinal excitability, but after-effects show substantial inter-individual variability. Functional magnetic resonance imaging (fMRI) can probe after-effects of TDCS on regional neural activity on a whole-brain level. Objective Using a double-blinded cross-over design, we investigated whether the individual change in corticospinal excitability after TDCS of M1-HAND is associated with changes in task-related regional activity in cortical motor areas. Methods Seventeen healthy volunteers (10 women) received 20 min of real (0.75 mA) or sham TDCS on separate days in randomized order. Real and sham TDCS used the classic bipolar set-up with the anode placed over right M1-HAND. Before and after each TDCS session, we recorded motor evoked potentials (MEP) from the relaxed left first dorsal interosseus muscle after single-pulse transcranial magnetic stimulation(TMS) of left M1-HAND and performed whole-brain fMRI at 3 Tesla while participants completed a visuomotor tracking task with their left hand. We also assessed the difference in MEP latency when applying anterior-posterior and latero-medial TMS pulses to the precentral hand knob (AP-LM MEP latency). Results Real TDCS had no consistent aftereffects on mean MEP amplitude, task-related activity or motor performance. Individual changes in MEP amplitude, measured directly after real TDCS showed a positive linear relationship with individual changes in task-related activity in the supplementary motor area and AP-LM MEP latency. Conclusion Functional aftereffects of classical bipolar anodal TDCS of M1-HAND on the motor system vary substantially across individuals. Physiological features upstream from the primary motor cortex may determine how anodal TDCS changes corticospinal excitability.
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Affiliation(s)
- Anke Ninija Karabanov
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Keiichiro Shindo
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Rehabilitation Medicine, Keio University School of Medicine, Shinjyuku-ku, Japan
| | - Yuko Shindo
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Rehabilitation Medicine, Keio University School of Medicine, Shinjyuku-ku, Japan
| | - Estelle Raffin
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology, Geneva, Switzerland
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.,Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
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29
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Pellegrini M, Zoghi M, Jaberzadeh S. Genetic Polymorphisms Do Not Predict Interindividual Variability to Cathodal Transcranial Direct Current Stimulation of the Primary Motor Cortex. Brain Connect 2020; 11:56-72. [PMID: 33198509 DOI: 10.1089/brain.2020.0762] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Introduction: High variability between individuals (i.e., interindividual variability) in response to transcranial direct current stimulation (tDCS) has become a commonly reported issue in the tDCS literature in recent years. Inherent genetic differences between individuals have been proposed as a contributing factor to observed response variability. This study investigated whether tDCS interindividual variability was genetically mediated. Methods: A large sample size of 61 healthy males received cathodal tDCS (c-tDCS) and sham-tDCS of the primary motor cortex at 1 mA and 10 min via 6 × 4 cm active and 7 × 5 cm return electrodes. Corticospinal excitability (CSE) was assessed via 25 single-pulse transcranial magnetic stimulation motor-evoked potentials (MEPs). Intracortical inhibition was assessed via twenty-five 3 msec interstimulus interval (ISI) paired-pulse MEPs, known as short-interval intracortical inhibition (SICI). Intracortical facilitation (ICF) was assessed via twenty-five 10 msec ISI paired-pulse MEPs. Gene variants encoding for excitatory and inhibitory neuroreceptors were determined via saliva samples. Predetermined thresholds and statistical cluster analyses were used to subgroup individuals. Results: Two distinct subgroups were identified, "responders" reducing CSE following c-tDCS and "nonresponders" showing no reduction or even increase in CSE. Differences in CSE between responders and nonresponders following c-tDCS were not explained by changes in SICI or ICF. Conclusions: No significant relationships were reported between gene variants and interindividual variability to c-tDCS, suggesting that the chosen gene variants did not influence the activity of the neuroreceptors involved in eliciting changes in CSE in responders following c-tDCS. In this largest c-tDCS study of its kind, novel insights were reported into the contribution genetic factors may play in observed interindividual variability to c-tDCS. Impact statement This study adds insight into the issue of interindividual variability to c-tDCS. It highlights not all individuals respond to c-tDCS similarly when exposed to the same stimulus parameters. This disparity in response to c-tDCS between individuals does not appear to be genetically mediated. For c-tDCS to progress to large-scale clinical application, reliability, predictability and reproducibility are essential. Systematically investigating factors contributing to interindividual variability take steps towards this progress the c-tDCS field towards the potential development of screening tools to determine clinical suitability to c-tDCS to ensure its application in those who may benefit the most.
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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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Ammann C, Guida P, Caballero-Insaurriaga J, Pineda-Pardo JA, Oliviero A, Foffani G. A framework to assess the impact of number of trials on the amplitude of motor evoked potentials. Sci Rep 2020; 10:21422. [PMID: 33293541 PMCID: PMC7722939 DOI: 10.1038/s41598-020-77383-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 10/30/2020] [Indexed: 12/12/2022] Open
Abstract
The amplitude of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) is a common yet highly variable measure of corticospinal excitability. The tradeoff between maximizing the number of trials and minimizing experimental time remains a hurdle. It is therefore important to establish how many trials should be used. The aim of this study is not to provide rule-of-thumb answers that may be valid only in specific experimental conditions, but to offer a more general framework to inform the decision about how many trials to use under different experimental conditions. Specifically, we present a set of equations that show how the number of trials affects single-subject MEP amplitude, population MEP amplitude, hypothesis testing and test-retest reliability, depending on the variability within and between subjects. The equations are derived analytically, validated with Monte Carlo simulations, and representatively applied to experimental data. Our findings show that the minimum number of trials for estimating single-subject MEP amplitude largely depends on the experimental conditions and on the error considered acceptable by the experimenter. Conversely, estimating population MEP amplitude and hypothesis testing are markedly more dependent on the number of subjects than on the number of trials. These tools and results help to clarify the impact of the number of trials in the design and reproducibility of past and future experiments.
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Affiliation(s)
- Claudia Ammann
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain
| | - Pasqualina Guida
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain
| | | | - José A Pineda-Pardo
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Guglielmo Foffani
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain.
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain.
- Hospital Nacional de Parapléjicos, Toledo, Spain.
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31
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Fried PJ, Santarnecchi E, Antal A, Bartres-Faz D, Bestmann S, Carpenter LL, Celnik P, Edwards D, Farzan F, Fecteau S, George MS, He B, Kim YH, Leocani L, Lisanby SH, Loo C, Luber B, Nitsche MA, Paulus W, Rossi S, Rossini PM, Rothwell J, Sack AT, Thut G, Ugawa Y, Ziemann U, Hallett M, Pascual-Leone A. Training in the practice of noninvasive brain stimulation: Recommendations from an IFCN committee. Clin Neurophysiol 2020; 132:819-837. [PMID: 33549501 DOI: 10.1016/j.clinph.2020.11.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 01/07/2023]
Abstract
As the field of noninvasive brain stimulation (NIBS) expands, there is a growing need for comprehensive guidelines on training practitioners in the safe and effective administration of NIBS techniques in their various research and clinical applications. This article provides recommendations on the structure and content of this training. Three different types of practitioners are considered (Technicians, Clinicians, and Scientists), to attempt to cover the range of education and responsibilities of practitioners in NIBS from the laboratory to the clinic. Basic or core competencies and more advanced knowledge and skills are discussed, and recommendations offered regarding didactic and practical curricular components. We encourage individual licensing and governing bodies to implement these guidelines.
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Affiliation(s)
- Peter J Fried
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Emiliano Santarnecchi
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - David Bartres-Faz
- Department of Medicine, Faculty of Medicine and Health Sciences & Institut de Neurociències, University of Barcelona, Institut d'Investigacions Biomèdiques (IDIBAPS), Barcelona, Spain
| | - Sven Bestmann
- Department for Movement and Clinical Neuroscience, Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, UK
| | - Linda L Carpenter
- Butler Hospital, Department of Psychiatry and Human Behavior, Alpert Medical School at Brown University, Providence, RI, USA
| | - Pablo Celnik
- Department of Physical Medicine and Rehabilitation, Johns Hopkins, School of Medicine, Baltimore, MD, USA
| | - Dylan Edwards
- Moss Rehabilitation Research Institute, Elkins Park, PA, USA; Edith Cowan University, Joondalup, Australia
| | - Faranak Farzan
- Simon Fraser University, British Columbia, Surrey, Mechatronic Systems Engineering, Canada
| | - Shirley Fecteau
- Faculty of Medicine, Université Laval, CERVO Brain Research Center, Quebec City, Quebec, Canada
| | - Mark S George
- Medical University of South Carolina, Charleston, SC, USA; Ralph H. Johnson VA Medical Center, Charlestown, SC, USA
| | - Bin He
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Yun-Hee Kim
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Letizia Leocani
- Institute of Experimental Neurology, Ospedale San Raffaele, and Department of Neurology, Vita-Salute San Raffaele University, Milano, Italy
| | - Sarah H Lisanby
- Division of Translational Research, National Institute of Mental Health, National Institutes of Health, Bethesda, MA, USA
| | - Colleen Loo
- School of Psychiatry and Black Dog Institute, University of New South Wales, Sydney, Australia
| | - Bruce Luber
- Noninvasive Neuromodulation Unit, National Institute of Mental Health, Bethesda, MD, USA
| | - Michael A Nitsche
- Leibniz Research Centre for Working Environment and Human Factors, Dept. Psychology and Neurosciences, Dortmund, Germany
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Simone Rossi
- Department of Medicine, Surgery and Neuroscience, Unit of Neurology and Clinical Neurophysiology, Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), University of Siena, Italy
| | - Paolo M Rossini
- Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele-Pisana, Rome, Italy
| | - John Rothwell
- UCL Institute of Neurology, University College, London, UK
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Gregor Thut
- Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - Yoshikazu Ugawa
- Department of Human Neurophysiology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Ulf Ziemann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institute of Health, Bethesda, MD, USA
| | - Alvaro Pascual-Leone
- Hinda and Arthur Marcus Institute for Aging Research and Deanna and Sidney Wolk Center for Memory Health, Hebrew SeniorLife and Department of Neurology, Harvard Medical School, Boston, MA, USA; Guttmann Brain Health Institute, Institut Guttmann, Universitat Autonoma, Barcelona, Spain.
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Jonker ZD, Gaiser C, Tulen JHM, Ribbers GM, Frens MA, Selles RW. No effect of anodal tDCS on motor cortical excitability and no evidence for responders in a large double-blind placebo-controlled trial. Brain Stimul 2020; 14:100-109. [PMID: 33197654 DOI: 10.1016/j.brs.2020.11.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 11/04/2020] [Accepted: 11/04/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) has emerged as a non-invasive brain stimulation technique. Most studies show that anodal tDCS increases cortical excitability. However, this effect has been found to be highly variable. OBJECTIVE To test the effect of anodal tDCS on cortical excitability and the interaction effect of two participant-specific factors that may explain individual differences in sensitivity to anodal tDCS: the Brain Derived Neurotrophic Factor Val66Met polymorphism (BDNF genotype) and the latency difference between anterior-posterior and lateromedial TMS pulses (APLM latency). METHODS In 62 healthy participants, cortical excitability over the left motor cortex was measured before and after anodal tDCS at 2 mA for 20 min in a pre-registered, double-blind, randomized, placebo-controlled trial with repeated measures. RESULTS We did not find a main effect of anodal tDCS, nor an interaction effect of the participant-specific predictors. Moreover, further analyses did not provide evidence for the existence of responders and non-responders. CONCLUSION This study indicates that anodal tDCS at 2 mA for 20 min may not reliably affect cortical excitability.
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Affiliation(s)
- Zeb D Jonker
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Rehabilitation Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands; Rijndam Rehabilitation Center, Rotterdam, the Netherlands
| | - Carolin Gaiser
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Joke H M Tulen
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Gerard M Ribbers
- Department of Rehabilitation Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands; Rijndam Rehabilitation Center, Rotterdam, the Netherlands
| | - Maarten A Frens
- Department of Neuroscience, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Ruud W Selles
- Department of Rehabilitation Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Plastic and Reconstructive Surgery, Erasmus University Medical Centre, Rotterdam, the Netherlands.
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Vitale F, Padrón I, Avenanti A, de Vega M. Enhancing Motor Brain Activity Improves Memory for Action Language: A tDCS Study. Cereb Cortex 2020; 31:1569-1581. [PMID: 33136142 DOI: 10.1093/cercor/bhaa309] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 08/17/2020] [Accepted: 08/28/2020] [Indexed: 11/14/2022] Open
Abstract
The embodied cognition approach to linguistic meaning posits that action language understanding is grounded in sensory-motor systems. However, evidence that the human motor cortex is necessary for action language memory is meager. To address this issue, in two groups of healthy individuals, we perturbed the left primary motor cortex (M1) by means of either anodal or cathodal transcranial direct current stimulation (tDCS), before participants had to memorize lists of manual action and attentional sentences. In each group, participants received sham and active tDCS in two separate sessions. Following anodal tDCS (a-tDCS), participants improved the recall of action sentences compared with sham tDCS. No similar effects were detected following cathodal tDCS (c-tDCS). Both a-tDCS and c-tDCS induced variable changes in motor excitability, as measured by motor-evoked potentials induced by transcranial magnetic stimulation. Remarkably, across groups, action-specific memory improvements were positively predicted by changes in motor excitability. We provide evidence that excitatory modulation of the motor cortex selectively improves performance in a task requiring comprehension and memory of action sentences. These findings indicate that M1 is necessary for accurate processing of linguistic meanings and thus provide causal evidence that high-order cognitive functions are grounded in the human motor system.
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Affiliation(s)
- Francesca Vitale
- Instituto Universitario de Neurociencia, Universidad de La Laguna, Santa Cruz de Tenerife 38200, Spain
| | - Iván Padrón
- Instituto Universitario de Neurociencia, Universidad de La Laguna, Santa Cruz de Tenerife 38200, Spain
| | - Alessio Avenanti
- Dipartimento di Psicologia, Centro studi e ricerche in Neuroscienze Cognitive, Alma Mater Studiorum-Università di Bologna, Cesena 47521, Italy
- Centro de Investigación en Neuropsicología y Neurociencias Cognitivas, Universidad Católica del Maule, Talca 3460000, Chile
| | - Manuel de Vega
- Instituto Universitario de Neurociencia, Universidad de La Laguna, Santa Cruz de Tenerife 38200, Spain
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Papasavvas CA, Schroeder GM, Diehl B, Baier G, Taylor PN, Wang Y. Band power modulation through intracranial EEG stimulation and its cross-session consistency. J Neural Eng 2020; 17:054001. [PMID: 33022661 PMCID: PMC7612301 DOI: 10.1088/1741-2552/abbecf] [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] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Direct electrical stimulation of the brain through intracranial electrodes is currently used to probe the epileptic brain as part of pre-surgical evaluation, and it is also being considered for therapeutic treatments through neuromodulation. In order to effectively modulate neural activity, a given neuromodulation design must elicit similar responses throughout the course of treatment. However, it is unknown whether intracranial electrical stimulation responses are consistent across sessions. The objective of this study was to investigate the within-subject, cross-session consistency of the electrophysiological effect of electrical stimulation delivered through intracranial electroencephalography (iEEG). APPROACH We analysed data from 79 epilepsy patients implanted with iEEG who underwent brain stimulation as part of a memory experiment. We quantified the effect of stimulation in terms of band power modulation and compared this effect from session to session. As a reference, we made the same measurements during baseline periods. MAIN RESULTS In most sessions, the effect of stimulation on band power could not be distinguished from baseline fluctuations of band power. Stimulation effect was consistent in a third of the session pairs, while the rest had a consistency measure not exceeding the baseline standards. Cross-session consistency was highly correlated with the degree of band power increase, and it also tended to be higher when the baseline conditions were more similar between sessions. SIGNIFICANCE These findings can inform our practices for designing neuromodulation with greater efficacy when using direct electrical brain stimulation as a therapeutic treatment.
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Affiliation(s)
- Christoforos A Papasavvas
- CNNP Lab (www.cnnp-lab.com), Interdisciplinary Computing and Complex BioSystems Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
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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: 5] [Impact Index Per Article: 1.3] [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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Pellegrini M, Zoghi M, Jaberzadeh S. A Checklist to Reduce Response Variability in Studies Using Transcranial Magnetic Stimulation for Assessment of Corticospinal Excitability: A Systematic Review of the Literature. Brain Connect 2020; 10:53-71. [PMID: 32093486 DOI: 10.1089/brain.2019.0715] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Response variability between individuals (interindividual variability) and within individuals (intraindividual variability) is an important issue in the transcranial magnetic stimulation (TMS) literature. This has raised questions of the validity of TMS to assess changes in corticospinal excitability (CSE) in a predictable and reliable manner. Several participant-specific factors contribute to this observed response variability with a current lack of consensus on the degree each factor contributes. This highlights a need for consistency and structure in reporting study designs and methodologies. Currently, there is no summarized review of the participant-specific factors that can be controlled and may contribute to response variability. This systematic review aimed to develop a checklist of methodological measures taken by previously published research to increase the homogeneity of participant selection criteria, preparation of participants before experimental testing, participant scheduling, and the instructions given to participants throughout experimental testing to minimize their effect on response variability. Seven databases were searched in full. Studies were included if CSE was measured via TMS and included methodological measures to increase the homogeneity of the participants. Eighty-four studies were included. Twenty-three included measures to increase participant selection homogeneity, 21 included measures to increase participant preparation homogeneity, while 61 included measures to increase participant scheduling and instructions during experimental testing homogeneity. These methodological measures were summarized into a user-friendly checklist with considerations, suggestions, and rationale/justification for their inclusion. This may provide the framework for further insights into ways to reduce response variability in TMS research.
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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, Victoria, Australia
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, Discipline of Physiotherapy, School of Allied Health, La Trobe University, Melbourne, Victoria, 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, Victoria, Australia
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Transcranial direct current stimulation for post-stroke dysphagia: a systematic review and meta-analysis of randomized controlled trials. J Neurol 2020; 268:293-304. [PMID: 32797300 DOI: 10.1007/s00415-020-10142-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 01/25/2023]
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) has been investigated as a tool for dysphagia recovery after stroke in several single-center randomized controlled trials (RCT). OBJECTIVE The aim of this investigation was to quantitatively evaluate the effect of tDCS on dysphagia recovery after a stroke utilizing a systematic review and meta-analysis. METHODS Major databases were searched through October 2019 using a pre-defined set of criteria. Any RCT investigating the efficacy of tDCS in post-stroke dysphagia using a standardized dysphagia scale as outcome measure was included. Studies were assessed for risk of bias and quality using the Physiotherapy Evidence Database (PEDro) scale. Effect sizes were calculated from extracted data and entered into a random effects analysis to obtain pooled estimates of the effect. RESULTS Seven RCTs with a total sample size of 217 patients fulfilled the criteria and were included in the analysis. The overall results revealed a small but statistically significant pooled effect size (0.31; CI 0.03, 0.59; p = 0.03). The subgroup which explored the stimulation intensity yielded a moderately significant effect size for the low-intensity stimulation group (g = 0.44; CI = 0.08, 0.81 vs. g = 0.15, CI - 0.30, 0.61). For the other subgroup analyses, neither comparisons of affected vs. unaffected hemisphere or acute vs. chronic stroke phase revealed a significant result. CONCLUSION This meta-analysis demonstrates a modest but significant beneficial effect of tDCS on improving post-stroke dysphagia. Whether benefits from this intervention are more pronounced in certain patient subgroups and with specific stimulation protocols requires further investigation.
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The Effects of 1 mA tACS and tRNS on Children/Adolescents and Adults: Investigating Age and Sensitivity to Sham Stimulation. Neural Plast 2020; 2020:8896423. [PMID: 32855633 PMCID: PMC7443018 DOI: 10.1155/2020/8896423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/24/2022] Open
Abstract
The aim of this study was to investigate the effect of transcranial random noise (tRNS) and transcranial alternating current (tACS) stimulation on motor cortex excitability in healthy children and adolescents. Additionally, based on our recent results on the individual response to sham in adults, we explored this effect in the pediatric population. We included 15 children and adolescents (10-16 years) and 28 adults (20-30 years). Participants were stimulated four times with 20 Hz and 140 Hz tACS, tRNS, and sham stimulation (1 mA) for 10 minutes over the left M1HAND. Single-pulse MEPs (motor evoked potential), short-interval intracortical inhibition, and facilitation were measured by TMS before and after stimulation (baseline, 0, 30, 60 minutes). We also investigated aspects of tolerability. According to the individual MEPs response immediately after sham stimulation compared to baseline (Wilcoxon signed-rank test), subjects were regarded as responders or nonresponders to sham. We did not find a significant age effect. Regardless of age, 140 Hz tACS led to increased excitability. Incidence and intensity of side effects did not differ between age groups or type of stimulation. Analyses on responders and nonresponders to sham stimulation showed effects of 140 Hz, 20 Hz tACS, and tRNS on single-pulse MEPs only for nonresponders. In this study, children and adolescents responded to 1 mA tRNS and tACS comparably to adults regarding the modulation of motor cortex excitability. This study contributes to the findings that noninvasive brain stimulation is well tolerated in children and adolescents including tACS, which has not been studied before. Finally, our study supports a modulating role of sensitivity to sham stimulation on responsiveness to a broader stimulation and age range.
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Machado L. Understanding cognition and how it changes with aging, brain disease, and lifestyle choices. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1796102] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Liana Machado
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand, Auckland, New Zealand
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Spampinato D, Celnik P. Multiple Motor Learning Processes in Humans: Defining Their Neurophysiological Bases. Neuroscientist 2020; 27:246-267. [PMID: 32713291 PMCID: PMC8151555 DOI: 10.1177/1073858420939552] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Learning new motor behaviors or adjusting previously learned actions to account for dynamic changes in our environment requires the operation of multiple distinct motor learning processes, which rely on different neuronal substrates. For instance, humans are capable of acquiring new motor patterns via the formation of internal model representations of the movement dynamics and through positive reinforcement. In this review, we will discuss how changes in human physiological markers, assessed with noninvasive brain stimulation techniques from distinct brain regions, can be utilized to provide insights toward the distinct learning processes underlying motor learning. We will summarize the findings from several behavioral and neurophysiological studies that have made efforts to understand how distinct processes contribute to and interact when learning new motor behaviors. In particular, we will extensively review two types of behavioral processes described in human sensorimotor learning: (1) a recalibration process of a previously learned movement and (2) acquiring an entirely new motor control policy, such as learning to play an instrument. The selected studies will demonstrate in-detail how distinct physiological mechanisms contributions change depending on the time course of learning and the type of behaviors being learned.
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Pellegrini M, Zoghi M, Jaberzadeh S. The effects of transcranial direct current stimulation on corticospinal and cortico-cortical excitability and response variability: Conventional versus high-definition montages. Neurosci Res 2020; 166:12-25. [PMID: 32610058 DOI: 10.1016/j.neures.2020.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 01/19/2023]
Abstract
Response variability following transcranial direct current stimulation (tDCS) highlights need for exploring different tDCS electrode montages. Corticospinal excitability (CSE), cortico-cortical excitability and intra-individual variability was compared following conventional and high-definition (HD) anodal (a-tDCS) and cathodal (c-tDCS) tDCS. Fifteen healthy males attended four sessions at-least one-week apart: conventional a-tDCS, conventional c-tDCS, HD-a-tDCS, HD-c-tDCS. TDCS was administered (1 mA, 10-minutes) over primary motor cortex (M1), via 6 × 4 cm active and 7 × 5 cm return electrodes (conventional tDCS) and 4 × 1 ring-electrodes 3.5 cm apart over M1 (HD-tDCS). For CSE, twenty-five single-pulse transcranial magnetic stimulation (TMS) peak-to-peak motor evoked potentials (MEP) were recorded at baseline, 0-minutes and 30-minutes post-tDCS. Twenty-five paired-pulse MEPs with 3-millisecond (ms) inter-pulse interval (IPI) and twenty-five at 10 ms assessed short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). MEP standardised z-values standard deviations represented intra-individual variability. No significant changes in CSE from baseline were reported for all four interventions. No significant differences were reported in CSE between conventional and HD a-tDCS, but significant differences between conventional and HD c-tDCS 0-minutes post-tDCS. Conventional tDCS significantly reduced intra-individual variability compared to HD-tDCS for a-tDCS (0-minutes) and c-tDCS (30-minutes). No changes were reported for SICI/ICF. These novel findings of increased intra-individual variability following HD-tDCS, at the current stimulus parameters, highlight need for further nuanced research and refinement to optimise the HD-tDCS dosage-response relationship.
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Affiliation(s)
- Michael Pellegrini
- Non-Invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia.
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, School of Allied Health, Discipline of Physiotherapy, La Trobe University, Melbourne, Australia
| | - Shapour Jaberzadeh
- Non-Invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
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Seidel-Marzi O, Ragert P. Anodal transcranial direct current stimulation reduces motor slowing in athletes and non-athletes. BMC Neurosci 2020; 21:26. [PMID: 32487077 PMCID: PMC7268396 DOI: 10.1186/s12868-020-00573-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 05/20/2020] [Indexed: 01/07/2023] Open
Abstract
Background Motor fatigability describes a phenomenon that occurs when exhaustive exercise or physically demanding tasks are executed over an extended period of time. Concerning fast repetitive movements, it is noticeable by a reduction in movement speed (motor slowing, MoSlo) and occurs due to both central and peripheral factors. The aim of the present study was to examine the presence of MoSlo during hand- (HTT) and foot-tapping tasks (FTT) comparing trained football (FB) and handball players (HB) and non-athletes (NA). Furthermore, we were interested in how far anodal transcranial direct current stimulation (tDCS) might be capable of modulating MoSlo as compared to sham. Methods A total number of 46 participants were enrolled in a sham-controlled, double-blinded, cross-over study. HTT and FTT were performed before, during, after as well as 30 min after 20 min of tDCS over the leg area of the primary motor cortex (M1). Results We could demonstrate that MoSlo during HTT and FTT is a general phenomenon that is observed independent of the type of sports and/or training status. Furthermore, we were able to show a tDCS-induced reduction in MoSlo specifically during FTT in both trained athletes and NA. No such effects could be observed for HTT, indicating local specificity of tDCS-induced effects on a behavioral level. Conclusion We could demonstrate that tDCS is capable of reducing motor fatigability during fast repetitive movements. These findings are of pivotal interest for many sports where fatigability resistance is a limiting factor in maintaining repetitive movement patterns.
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Affiliation(s)
- Oliver Seidel-Marzi
- Institute for General Kinesiology and Exercise Science, Faculty of Sport Science, University of Leipzig, Jahnallee 59, 04109, Leipzig, Germany. .,Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany.
| | - Patrick Ragert
- Institute for General Kinesiology and Exercise Science, Faculty of Sport Science, University of Leipzig, Jahnallee 59, 04109, Leipzig, Germany.,Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany
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Transcranial Direct Current Stimulation for Motor Recovery Following Brain Injury. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2020. [DOI: 10.1007/s40141-020-00262-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Esmaeilpour Z, Shereen AD, Ghobadi‐Azbari P, Datta A, Woods AJ, Ironside M, O'Shea J, Kirk U, Bikson M, Ekhtiari H. Methodology for tDCS integration with fMRI. Hum Brain Mapp 2020; 41:1950-1967. [PMID: 31872943 PMCID: PMC7267907 DOI: 10.1002/hbm.24908] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 11/09/2019] [Accepted: 12/10/2019] [Indexed: 12/28/2022] Open
Abstract
Understanding and reducing variability of response to transcranial direct current stimulation (tDCS) requires measuring what factors predetermine sensitivity to tDCS and tracking individual response to tDCS. Human trials, animal models, and computational models suggest structural traits and functional states of neural systems are the major sources of this variance. There are 118 published tDCS studies (up to October 1, 2018) that used fMRI as a proxy measure of neural activation to answer mechanistic, predictive, and localization questions about how brain activity is modulated by tDCS. FMRI can potentially contribute as: a measure of cognitive state-level variance in baseline brain activation before tDCS; inform the design of stimulation montages that aim to target functional networks during specific tasks; and act as an outcome measure of functional response to tDCS. In this systematic review, we explore methodological parameter space of tDCS integration with fMRI spanning: (a) fMRI timing relative to tDCS (pre, post, concurrent); (b) study design (parallel, crossover); (c) control condition (sham, active control); (d) number of tDCS sessions; (e) number of follow up scans; (f) stimulation dose and combination with task; (g) functional imaging sequence (BOLD, ASL, resting); and (h) additional behavioral (cognitive, clinical) or quantitative (neurophysiological, biomarker) measurements. Existing tDCS-fMRI literature shows little replication across these permutations; few studies used comparable study designs. Here, we use a representative sample study with both task and resting state fMRI before and after tDCS in a crossover design to discuss methodological confounds. We further outline how computational models of current flow should be combined with imaging data to understand sources of variability. Through the representative sample study, we demonstrate how modeling and imaging methodology can be integrated for individualized analysis. Finally, we discuss the importance of conducting tDCS-fMRI with stimulation equipment certified as safe to use inside the MR scanner, and of correcting for image artifacts caused by tDCS. tDCS-fMRI can address important questions on the functional mechanisms of tDCS action (e.g., target engagement) and has the potential to support enhancement of behavioral interventions, provided studies are designed rationally.
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Affiliation(s)
- Zeinab Esmaeilpour
- Neural Engineering Laboratory, Department of Biomedical EngineeringThe City College of the City University of New York, City College Center for Discovery and InnovationNew YorkNew York
| | - A. Duke Shereen
- Advanced Science Research Center, The Graduate CenterCity University of New YorkNew YorkNew York
| | | | | | - Adam J. Woods
- Center for Cognitive Aging and Memory, McKnight Brain Institute, Department of Clinical and Health PsychologyUniversity of FloridaGainesvilleFlorida
| | - Maria Ironside
- Center for Depression, Anxiety and Stress Research, McLean HospitalBelmontMassachusetts
- Department of PsychiatryHarvard Medical SchoolBostonMassachusetts
| | - Jacinta O'Shea
- Nuffield Department of Clinical Neuroscience, Medical Science DivisionUniversity of OxfordOxfordEnglandUK
| | - Ulrich Kirk
- Department of PsychologyUniversity of Southern DenmarkOdenseDenmark
| | - Marom Bikson
- Neural Engineering Laboratory, Department of Biomedical EngineeringThe City College of the City University of New York, City College Center for Discovery and InnovationNew YorkNew York
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45
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Klink K, Peter J, Wyss P, Klöppel S. Transcranial Electric Current Stimulation During Associative Memory Encoding: Comparing tACS and tDCS Effects in Healthy Aging. Front Aging Neurosci 2020; 12:66. [PMID: 32256337 PMCID: PMC7090128 DOI: 10.3389/fnagi.2020.00066] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 02/25/2020] [Indexed: 12/02/2022] Open
Abstract
Associative memory is one of the first cognitive functions negatively affected by healthy and pathological aging processes. Non-invasive brain stimulation (NIBS) techniques are easily administrable tools to support memory. However, the optimal stimulation parameters inducing a reliable positive effect on older adult’s memory performance remain mostly unclear. In our randomized, double-blind, cross-over study, 28 healthy older adults (16 females; 71.18 + 6.42 years of age) received anodal transcranial direct (tDCS), alternating current in the theta range (tACS), and sham stimulation over the left ventrolateral prefrontal cortex (VLPFC) each once during encoding. We tested associative memory performance with cued recall and recognition tasks after a retention period and again on the following day. Overall, neither tDCS nor tACS showed effects on associative memory performance. Further analysis revealed a significant difference for performance on the cued recall task under tACS compared to sham when accounting for age. Our results suggest that tACS might be more effective to improve associative memory performance than tDCS in higher aged samples.
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Affiliation(s)
- Katharina Klink
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Jessica Peter
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Patric Wyss
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Stefan Klöppel
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
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46
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Neri F, Mencarelli L, Menardi A, Giovannelli F, Rossi S, Sprugnoli G, Rossi A, Pascual-Leone A, Salvador R, Ruffini G, Santarnecchi E. A novel tDCS sham approach based on model-driven controlled shunting. Brain Stimul 2020; 13:507-516. [PMID: 31926812 DOI: 10.1016/j.brs.2019.11.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/13/2019] [Accepted: 11/02/2019] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique able to transiently modulate brain activity, is surging as one of the most promising therapeutic solutions in many neurological and psychiatric disorders. However, profound limitations exist in current placebo (sham) protocols that limit single- and double-blinding, especially in non-naïve subjects. OBJECTIVE To ensure better blinding and strengthen reliability of tDCS studies and trials, we tested a new optimization algorithm aimed at creating an "active" sham tDCS condition (ActiSham hereafter) capable of inducing the same scalp sensations perceived during real stimulation while preventing currents from reaching the cortex and cause changes in brain excitability. METHODS A novel model-based multielectrode technique - optimizing the location and currents of a set of small electrodes placed on the scalp - was used to control the relative amount of current delivered transcranially in real and placebo multichannel tDCS conditions. The presence, intensity and localization of scalp sensations during tDCS was evaluated by means of a specifically designed questionnaire administered to the participants. We compared blinding ratings by directly addressing subjects' ability to discriminate across conditions for both traditional (Bifocal-tDCS and Sham, using sponge electrodes) and our novel multifocal approach (both real Multifocal-tDCS and ActiSham). Changes in corticospinal excitability were monitored based on Motor Evoked Potentials (MEPs) recorded via concurrent Transcranial Magnetic Stimulation (TMS) and electromyography (EMG). RESULTS Participants perceived Multifocal-tDCS and ActiSham similarly in terms of both localization and intensity of scalp sensations, whereas traditional Bifocal stimulation was rated as more painful and annoying compared to its Sham counterpart. Additionally, differences in scalp localization were reported for active/sham Bifocal-tDCS, with Sham tDCS inducing more widespread itching and burning sensations. As for MEPs amplitude, a main effect of stimulation was found when comparing Bifocal-Sham and ActiSham (F(1,13) = 6.67, p = .023), with higher MEPs amplitudes after the application of Bifocal-Sham. CONCLUSIONS Compared to traditional Bifocal-tDCS, ActiSham offers better participants' blinding by inducing very similar scalp sensations to those of real Multifocal tDCS both in terms of intensity and localization, while not affecting corticospinal excitability.
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Affiliation(s)
- Francesco Neri
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - Lucia Mencarelli
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - Arianna Menardi
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - Fabio Giovannelli
- Section of Psychology, Department of Neuroscience, Psychology, Drug Research, Child Health, University of Florence, Florence, Italy
| | - Simone Rossi
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Department of Medicine, Surgery and Neuroscience, University of Siena School of Medicine, Siena, Italy
| | - Giulia Sprugnoli
- Radiology Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Alessandro Rossi
- Department of Medicine, Surgery and Neuroscience, University of Siena School of Medicine, Siena, Italy
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | | | - Emiliano Santarnecchi
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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47
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Gibson BC, Mullins TS, Heinrich MD, Witkiewitz K, Yu AB, Hansberger JT, Clark VP. Transcranial direct current stimulation facilitates category learning. Brain Stimul 2020; 13:393-400. [DOI: 10.1016/j.brs.2019.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 11/06/2019] [Accepted: 11/20/2019] [Indexed: 10/25/2022] Open
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Guerra A, López-Alonso V, Cheeran B, Suppa A. Variability in non-invasive brain stimulation studies: Reasons and results. Neurosci Lett 2020; 719:133330. [DOI: 10.1016/j.neulet.2017.12.058] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/18/2017] [Accepted: 12/27/2017] [Indexed: 01/22/2023]
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49
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Workman CD, Kamholz J, Rudroff T. Increased leg muscle fatigability during 2 mA and 4 mA transcranial direct current stimulation over the left motor cortex. Exp Brain Res 2020; 238:333-343. [PMID: 31919540 DOI: 10.1007/s00221-019-05721-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022]
Abstract
Transcranial direct current stimulation (tDCS) using intensities ≤ 2 mA on physical and cognitive outcomes has been extensively investigated. Studies comparing the effects of different intensities of tDCS have yielded mixed results and little is known about how higher intensities (> 2 mA) affect outcomes. This study examined the effects of tDCS at 2 mA and 4 mA on leg muscle fatigability. This was a double-blind, randomized, sham-controlled study. Sixteen healthy young adults underwent tDCS at three randomly ordered intensities (sham, 2 mA, 4 mA). Leg muscle fatigability of both legs was assessed via isokinetic fatigue testing (40 maximal reps, 120°/s). Torque- and work-derived fatigue indices (FI-T and FI-W, respectively), as well as total work performed (TW), were calculated. FI-T of the right knee extensors indicated increased fatigability in 2 mA and 4 mA compared with sham (p = 0.01, d = 0.73 and p < 0.001, d = 1.61, respectively). FI-W of the right knee extensors also indicated increased fatigability in 2 mA and 4 mA compared to sham (p = 0.01, d = 0.57 and p < 0.001, d = 1.12, respectively) and 4 mA compared with 2 mA (p = 0.034, d = 0.37). tDCS intensity did not affect TW performed. The 2 mA and 4 mA tDCS intensities increased the fatigability of the right knee extensors in young, healthy participants, potentially from altered motor unit recruitment/discharge rate or cortical hyperexcitability. Despite this increase in fatigability, the TW performed in both these conditions was not different from sham.
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Affiliation(s)
- Craig D Workman
- Department of Health and Human Physiology, University of Iowa, E432 Field House, Iowa City, IA, 52242, USA
| | - John Kamholz
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Thorsten Rudroff
- Department of Health and Human Physiology, University of Iowa, E432 Field House, Iowa City, IA, 52242, USA.
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.
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50
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Expanding the parameter space of anodal transcranial direct current stimulation of the primary motor cortex. Sci Rep 2019; 9:18185. [PMID: 31796827 PMCID: PMC6890804 DOI: 10.1038/s41598-019-54621-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 11/18/2019] [Indexed: 12/20/2022] Open
Abstract
Size and duration of the neuroplastic effects of tDCS depend on stimulation parameters, including stimulation duration and intensity of current. The impact of stimulation parameters on physiological effects is partially non-linear. To improve the utility of this intervention, it is critical to gather information about the impact of stimulation duration and intensity on neuroplasticity, while expanding the parameter space to improve efficacy. Anodal tDCS of 1–3 mA current intensity was applied for 15–30 minutes to study motor cortex plasticity. Sixteen healthy right-handed non-smoking volunteers participated in 10 sessions (intensity-duration pairs) of stimulation in a randomized cross-over design. Transcranial magnetic stimulation (TMS)-induced motor-evoked potentials (MEP) were recorded as outcome measures of tDCS effects until next evening after tDCS. All active stimulation conditions enhanced motor cortex excitability within the first 2 hours after stimulation. We observed no significant differences between the three stimulation intensities and durations on cortical excitability. A trend for larger cortical excitability enhancements was however observed for higher current intensities (1 vs 3 mA). These results add information about intensified tDCS protocols and suggest that the impact of anodal tDCS on neuroplasticity is relatively robust with respect to gradual alterations of stimulation intensity, and duration.
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