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Callejón-Leblic MA, Lazo-Maestre M, Fratter A, Ropero-Romero F, Sánchez-Gómez S, Reina-Tosina J. A full-head model to investigate intra and extracochlear electric fields in cochlear implant stimulation. Phys Med Biol 2024; 69:155010. [PMID: 38925131 DOI: 10.1088/1361-6560/ad5c38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 06/26/2024] [Indexed: 06/28/2024]
Abstract
Objective.Despite the widespread use and technical improvement of cochlear implant (CI) devices over past decades, further research into the bioelectric bases of CI stimulation is still needed. Various stimulation modes implemented by different CI manufacturers coexist, but their true clinical benefit remains unclear, probably due to the high inter-subject variability reported, which makes the prediction of CI outcomes and the optimal fitting of stimulation parameters challenging. A highly detailed full-head model that includes a cochlea and an electrode array is developed in this study to emulate intracochlear voltages and extracochlear current pathways through the head in CI stimulation.Approach.Simulations based on the finite element method were conducted under monopolar, bipolar, tripolar (TP), and partial TP modes, as well as for apical, medial, and basal electrodes. Variables simulated included: intracochlear voltages, electric field (EF) decay, electric potentials at the scalp and extracochlear currents through the head. To better understand CI side effects such as facial nerve stimulation, caused by spurious current leakage out from the cochlea, special emphasis is given to the analysis of the EF over the facial nerve.Main results.The model reasonably predicts EF magnitudes and trends previously reported in CI users. New relevant extracochlear current pathways through the head and brain tissues have been identified. Simulated results also show differences in the magnitude and distribution of the EF through different segments of the facial nerve upon different stimulation modes and electrodes, dependent on nerve and bone tissue conductivities.Significance.Full-head models prove useful tools to model intra and extracochlear EFs in CI stimulation. Our findings could prove useful in the design of future experimental studies to contrast FNS mechanisms upon stimulation of different electrodes and CI modes. The full-head model developed is freely available for the CI community for further research and use.
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Affiliation(s)
- M A Callejón-Leblic
- Otorhinolaryngology Department, Virgen Macarena University Hospital, Seville 41009, Spain
- Oticon Medical, 28108 Madrid, Spain
- Dept. Signal Theory and Communications, Biomedical Engineering Group, University of Seville, Seville 41092, Spain
| | - M Lazo-Maestre
- Otorhinolaryngology Department, Virgen Macarena University Hospital, Seville 41009, Spain
| | - A Fratter
- Oticon Medical, 06220 Vallauris, France
| | - F Ropero-Romero
- Otorhinolaryngology Department, Virgen Macarena University Hospital, Seville 41009, Spain
| | - S Sánchez-Gómez
- Otorhinolaryngology Department, Virgen Macarena University Hospital, Seville 41009, Spain
| | - J Reina-Tosina
- Dept. Signal Theory and Communications, Biomedical Engineering Group, University of Seville, Seville 41092, Spain
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Legros A, Nissi J, Laakso I, Duprez J, Kavet R, Modolo J. Thresholds and mechanisms of human magnetophosphene perception induced by low frequency sinusoidal magnetic fields. Brain Stimul 2024; 17:668-675. [PMID: 38740182 DOI: 10.1016/j.brs.2024.05.004] [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: 12/22/2023] [Revised: 05/07/2024] [Accepted: 05/07/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND Virtually everyone is exposed to power-frequency MF (50/60 Hz), inducing in our body electric fields and currents, potentially modulating brain function. MF-induced electric fields within the central nervous system can generate flickering visual perceptions (magnetophosphenes), which form the basis of international MF exposure guidelines and recommendations protecting workers and the general public. However, magnetophosphene perception thresholds were estimated 40 years ago in a small, unreplicated study with significant uncertainties and leaving open the question of the involved interaction site. METHODS We used a stimulation modality termed transcranial alternating magnetic stimulation (tAMS), delivering in situ sinusoidal electric fields comparable to transcranial alternating current stimulation (tACS). Magnetophosphene perception was quantified in 81 volunteers exposed to MF (eye or occipital exposure) between 0 and 50 mT at frequencies of 20, 50, 60 and 100 Hz. RESULTS Reliable magnetophosphene perception was induced with tAMS without any scalp sensation, a major advantage as compared to tACS. Frequency-dependent thresholds were quantified using binary logistic regressions hence allowing to establish condition dependent probabilities of perception. Results support an interaction between induced current density and retinal rod cells. CONCLUSION Beyond fundamental and immediate implications for international safety guidelines, and for identifying the interaction site underlying phosphene perception (ubiquitous in tACS experiments), our results support exploring the potential of tAMS for the differential diagnosis of retinal disorders and neuromodulation therapy.
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Affiliation(s)
- Alexandre Legros
- Human Threshold Research Group, Lawson Health Research Institute, London, ON, Canada; Departments of Medical Biophysics and Medical Imaging Western University, London, ON, Canada; School of Kinesiology, Western University, London, ON, Canada; EuroMov Digital Health in Motion, University of Montpellier and IMT Mines Ales, Montpellier, France.
| | - Janita Nissi
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Ilkka Laakso
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Joan Duprez
- Univ Rennes, INSERM, LTSI - U1099, F-35000, France
| | | | - Julien Modolo
- Human Threshold Research Group, Lawson Health Research Institute, London, ON, Canada; Univ Rennes, INSERM, LTSI - U1099, F-35000, France
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Daoud M, Durelle C, Fierain A, N EY, Wendling F, Ruffini G, Benquet P, Bartolomei F. Long-term Effect of Multichannel tDCS Protocol in Patients with Central Cortex Epilepsies Associated with Epilepsia Partialis Continua. Brain Topogr 2024:10.1007/s10548-024-01045-3. [PMID: 38446345 DOI: 10.1007/s10548-024-01045-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 02/21/2024] [Indexed: 03/07/2024]
Abstract
Epilepsia partialis continua (EPC) is a rare type of focal motor status epilepticus that causes continuous muscle jerking in a specific part of the body. Experiencing this type of seizure, along with other seizure types, such as focal motor seizures and focal to bilateral tonic-clonic seizures, can result in a disabling situation. Non-invasive brain stimulation methods like transcranial direct current stimulation (tDCS) show promise in reducing seizure frequency (SF) when medications are ineffective. However, research on tDCS for EPC and related seizures is limited. We evaluated personalized multichannel tDCS in drug-resistant EPC of diverse etiologies for long-term clinical efficacy We report three EPC patients undergoing a long-term protocol of multichannel tDCS. The patients received several cycles (11, 9, and 3) of five consecutive days of stimulation at 2 mA for 2 × 20 min, targeting the epileptogenic zone (EZ), including the central motor cortex with cathodal electrodes. The primary measurement was SF changes. In three cases, EPC was due to Rasmussen's Encephalitis (case 1), focal cortical dysplasia (case 2), or remained unknown (case 3). tDCS cycles were administered over 6 to 22 months. The outcomes comprised a reduction of at least 75% in seizure frequency for two patients, and in one case, a complete cessation of severe motor seizures. However, tDCS had no substantial impact on the continuous myoclonus characterizing EPC. No serious side effects were reported. Long-term application of tDCS cycles is well tolerated and can lead to a considerable reduction in disabling seizures in patients with various forms of epilepsy with EPC.
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Affiliation(s)
- M Daoud
- Aix-Marseille Univ, INSERM U1106, Institut de Neurosciences des Systèmes, Marseille, France
| | - C Durelle
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France
| | - A Fierain
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France
| | - El Youssef N
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France
| | - F Wendling
- Univ Rennes, INSERM, LTSI-U1099, Rennes, F-35000, France
| | - G Ruffini
- Neuroelectrics Barcelona, Av. Tibidabo 47 bis, Barcelona, 08035, Spain
| | - P Benquet
- Univ Rennes, INSERM, LTSI-U1099, Rennes, F-35000, France
| | - F Bartolomei
- Aix-Marseille Univ, INSERM U1106, Institut de Neurosciences des Systèmes, Marseille, France.
- Service d'Epileptologie et de Rythmologie cérébrale, APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, 264 Rue Saint-Pierre, Marseille, 13005, France.
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Romo-Nava F, Awosika OO, Basu I, Blom TJ, Welge J, Datta A, Guillen A, Guerdjikova AI, Fleck DE, Georgiev G, Mori N, Patino LR, DelBello MP, McNamara RK, Buijs RM, Frye MA, McElroy SL. Effect of non-invasive spinal cord stimulation in unmedicated adults with major depressive disorder: a pilot randomized controlled trial and induced current flow pattern. Mol Psychiatry 2024; 29:580-589. [PMID: 38123726 PMCID: PMC11153138 DOI: 10.1038/s41380-023-02349-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023]
Abstract
Converging theoretical frameworks suggest a role and a therapeutic potential for spinal interoceptive pathways in major depressive disorder (MDD). Here, we aimed to evaluate the antidepressant effects and tolerability of transcutaneous spinal direct current stimulation (tsDCS) in MDD. This was a double-blind, randomized, sham-controlled, parallel group, pilot clinical trial in unmedicated adults with moderate MDD. Twenty participants were randomly allocated (1:1 ratio) to receive "active" 2.5 mA or "sham" anodal tsDCS sessions with a thoracic (anode; T10)/right shoulder (cathode) electrode montage 3 times/week for 8 weeks. Change in depression severity (MADRS) scores (prespecified primary outcome) and secondary clinical outcomes were analyzed with ANOVA models. An E-Field model was generated using the active tsDCS parameters. Compared to sham (n = 9), the active tsDCS group (n = 10) showed a greater baseline to endpoint decrease in MADRS score with a large effect size (-14.6 ± 2.5 vs. -21.7 ± 2.3, p = 0.040, d = 0.86). Additionally, compared to sham, active tsDCS induced a greater decrease in MADRS "reported sadness" item (-1.8 ± 0.4 vs. -3.2 ± 0.4, p = 0.012), and a greater cumulative decrease in pre/post tsDCS session diastolic blood pressure change from baseline to endpoint (group difference: 7.9 ± 3.7 mmHg, p = 0.039). Statistical trends in the same direction were observed for MADRS "pessimistic thoughts" item and week-8 CGI-I scores. No group differences were observed in adverse events (AEs) and no serious AEs occurred. The current flow simulation showed electric field at strength within the neuromodulation range (max. ~0.45 V/m) reaching the thoracic spinal gray matter. The results from this pilot study suggest that tsDCS is feasible, well-tolerated, and shows therapeutic potential in MDD. This work also provides the initial framework for the cautious exploration of non-invasive spinal cord neuromodulation in the context of mental health research and therapeutics. The underlying mechanisms warrant further investigation. Clinicaltrials.gov registration: NCT03433339 URL: https://clinicaltrials.gov/ct2/show/NCT03433339 .
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Affiliation(s)
- Francisco Romo-Nava
- Lindner Center of HOPE, Mason, OH, USA.
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
| | - Oluwole O Awosika
- Department of Neurology and Rehabilitation Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ishita Basu
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Thomas J Blom
- Lindner Center of HOPE, Mason, OH, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jeffrey Welge
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Abhishek Datta
- Research and Development, Soterix Medical, Inc, New York, NY, USA
| | | | - Anna I Guerdjikova
- Lindner Center of HOPE, Mason, OH, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - David E Fleck
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | - Nicole Mori
- Lindner Center of HOPE, Mason, OH, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Luis R Patino
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Melissa P DelBello
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Robert K McNamara
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ruud M Buijs
- Departamento de Fisiología Celular y Biología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, México
| | - Mark A Frye
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA
| | - Susan L McElroy
- Lindner Center of HOPE, Mason, OH, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Cabrera-Álvarez J, Sánchez-Claros J, Carrasco-Gómez M, del Cerro-León A, Gómez-Ariza CJ, Maestú F, Mirasso CR, Susi G. Understanding the effects of cortical gyrification in tACS: insights from experiments and computational models. Front Neurosci 2023; 17:1223950. [PMID: 37655010 PMCID: PMC10467425 DOI: 10.3389/fnins.2023.1223950] [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: 05/16/2023] [Accepted: 07/25/2023] [Indexed: 09/02/2023] Open
Abstract
The alpha rhythm is often associated with relaxed wakefulness or idling and is altered by various factors. Abnormalities in the alpha rhythm have been linked to several neurological and psychiatric disorders, including Alzheimer's disease. Transcranial alternating current stimulation (tACS) has been proposed as a potential tool to restore a disrupted alpha rhythm in the brain by stimulating at the individual alpha frequency (IAF), although some research has produced contradictory results. In this study, we applied an IAF-tACS protocol over parieto-occipital areas to a sample of healthy subjects and measured its effects over the power spectra. Additionally, we used computational models to get a deeper understanding of the results observed in the experiment. Both experimental and numerical results showed an increase in alpha power of 8.02% with respect to the sham condition in a widespread set of regions in the cortex, excluding some expected parietal regions. This result could be partially explained by taking into account the orientation of the electric field with respect to the columnar structures of the cortex, showing that the gyrification in parietal regions could generate effects in opposite directions (hyper-/depolarization) at the same time in specific brain regions. Additionally, we used a network model of spiking neuronal populations to explore the effects that these opposite polarities could have on neural activity, and we found that the best predictor of alpha power was the average of the normal components of the electric field. To sum up, our study sheds light on the mechanisms underlying tACS brain activity modulation, using both empirical and computational approaches. Non-invasive brain stimulation techniques hold promise for treating brain disorders, but further research is needed to fully understand and control their effects on brain dynamics and cognition. Our findings contribute to this growing body of research and provide a foundation for future studies aimed at optimizing the use of non-invasive brain stimulation in clinical settings.
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Affiliation(s)
- Jesús Cabrera-Álvarez
- Centre for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
- Department of Experimental Psychology, Complutense University of Madrid, Madrid, Spain
| | - Jaime Sánchez-Claros
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus UIB, Palma de Mallorca, Spain
| | - Martín Carrasco-Gómez
- Centre for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
- Biomedical Image Technologies, ETSI Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain
| | - Alberto del Cerro-León
- Centre for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
- Department of Experimental Psychology, Complutense University of Madrid, Madrid, Spain
| | | | - Fernando Maestú
- Centre for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
- Department of Experimental Psychology, Complutense University of Madrid, Madrid, Spain
| | - Claudio R. Mirasso
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus UIB, Palma de Mallorca, Spain
| | - Gianluca Susi
- Centre for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
- Department of Structure of Matter, Thermal Physics and Electronics, School of Physics, Complutense University of Madrid, Madrid, Spain
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Majdi A, Asamoah B, Mc Laughlin M. Reinterpreting published tDCS results in terms of a cranial and cervical nerve co-stimulation mechanism. Front Hum Neurosci 2023; 17:1101490. [PMID: 37415857 PMCID: PMC10320219 DOI: 10.3389/fnhum.2023.1101490] [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: 11/17/2022] [Accepted: 05/31/2023] [Indexed: 07/08/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation method that has been used to alter cognition in hundreds of experiments. During tDCS, a low-amplitude current is delivered via scalp electrodes to create a weak electric field in the brain. The weak electric field causes membrane polarization in cortical neurons directly under the scalp electrodes. It is generally assumed that this mechanism causes the observed effects of tDCS on cognition. However, it was recently shown that some tDCS effects are not caused by the electric field in the brain but rather via co-stimulation of cranial and cervical nerves in the scalp that also have neuromodulatory effects that can influence cognition. This peripheral nerve co-stimulation mechanism is not controlled for in tDCS experiments that use the standard sham condition. In light of this new evidence, results from previous tDCS experiments could be reinterpreted in terms of a peripheral nerve co-stimulation mechanism. Here, we selected six publications that reported tDCS effects on cognition and attributed the effects to the electric field in the brain directly under the electrode. We then posed the question: given the known neuromodulatory effects of cranial and cervical nerve stimulation, could the reported results also be understood in terms of tDCS peripheral nerve co-stimulation? We present our re-interpretation of these results as a way to stimulate debate within the neuromodulation field and as a food-for-thought for researchers designing new tDCS experiments.
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Affiliation(s)
- Alireza Majdi
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Boateng Asamoah
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Myles Mc Laughlin
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
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7
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Karatum O, Han M, Erdogan ET, Karamursel S, Nizamoglu S. Physical mechanisms of emerging neuromodulation modalities. J Neural Eng 2023; 20:031001. [PMID: 37224804 DOI: 10.1088/1741-2552/acd870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 05/24/2023] [Indexed: 05/26/2023]
Abstract
One of the ultimate goals of neurostimulation field is to design materials, devices and systems that can simultaneously achieve safe, effective and tether-free operation. For that, understanding the working mechanisms and potential applicability of neurostimulation techniques is important to develop noninvasive, enhanced, and multi-modal control of neural activity. Here, we review direct and transduction-based neurostimulation techniques by discussing their interaction mechanisms with neurons via electrical, mechanical, and thermal means. We show how each technique targets modulation of specific ion channels (e.g. voltage-gated, mechanosensitive, heat-sensitive) by exploiting fundamental wave properties (e.g. interference) or engineering nanomaterial-based systems for efficient energy transduction. Overall, our review provides a detailed mechanistic understanding of neurostimulation techniques together with their applications toin vitro, in vivo, and translational studies to guide the researchers toward developing more advanced systems in terms of noninvasiveness, spatiotemporal resolution, and clinical applicability.
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Affiliation(s)
- Onuralp Karatum
- Department of Electrical and Electronics Engineering, Koc University, Istanbul 34450, Turkey
| | - Mertcan Han
- Department of Electrical and Electronics Engineering, Koc University, Istanbul 34450, Turkey
| | - Ezgi Tuna Erdogan
- Department of Physiology, Koc University School of Medicine, Istanbul 34450, Turkey
| | - Sacit Karamursel
- Department of Physiology, Koc University School of Medicine, Istanbul 34450, Turkey
| | - Sedat Nizamoglu
- Department of Electrical and Electronics Engineering, Koc University, Istanbul 34450, Turkey
- Department of Biomedical Science and Engineering, Koc University, Istanbul 34450, Turkey
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Gaugain G, Quéguiner L, Bikson M, Sauleau R, Zhadobov M, Modolo J, Nikolayev D. Quasi-static approximation error of electric field analysis for transcranial current stimulation. J Neural Eng 2023; 20. [PMID: 36621858 DOI: 10.1088/1741-2552/acb14d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023]
Abstract
Objective.Numerical modeling of electric fields induced by transcranial alternating current stimulation (tACS) is currently a part of the standard procedure to predict and understand neural response. Quasi-static approximation (QSA) for electric field calculations is generally applied to reduce the computational cost. Here, we aimed to analyze and quantify the validity of the approximation over a broad frequency range.Approach.We performed electromagnetic modeling studies using an anatomical head model and considered approximations assuming either a purely ohmic medium (i.e. static formulation) or a lossy dielectric medium (QS formulation). The results were compared with the solution of Maxwell's equations in the cases of harmonic and pulsed signals. Finally, we analyzed the effect of electrode positioning on these errors.Main results.Our findings demonstrate that the QSA is valid and produces a relative error below 1% up to 1.43 MHz. The largest error is introduced in the static case, where the error is over 1% across the entire considered spectrum and as high as 20% in the brain at 10 Hz. We also highlight the special importance of considering the capacitive effect of tissues for pulsed waveforms, which prevents signal distortion induced by the purely ohmic approximation. At the neuron level, the results point a difference of sense electric field as high as 22% at focusing point, impacting pyramidal cells firing times.Significance.QSA remains valid in the frequency range currently used for tACS. However, neglecting permittivity (static formulation) introduces significant error for both harmonic and non-harmonic signals. It points out that reliable low frequency dielectric data are needed for accurate transcranial current stimulation numerical modeling.
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Affiliation(s)
- Gabriel Gaugain
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Lorette Quéguiner
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, United States of America
| | - Ronan Sauleau
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Maxim Zhadobov
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Julien Modolo
- Univ Rennes, INSERM, LTSI (Laboratoire traitement du signal et de l'image) - U1099, 35000 Rennes, France
| | - Denys Nikolayev
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
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Quantum control of optoelectronic and thermodynamic properties of dopamine molecule in external electric field : A DFT and TD-DFT study. COMPUT THEOR CHEM 2023. [DOI: 10.1016/j.comptc.2023.114051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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10
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Yuan K, Ti CHE, Wang X, Chen C, Lau CCY, Chu WCW, Tong RKY. Individual electric field predicts functional connectivity changes after anodal transcranial direct-current stimulation in chronic stroke. Neurosci Res 2023; 186:21-32. [PMID: 36220454 DOI: 10.1016/j.neures.2022.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 09/29/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022]
Abstract
The neuromodulation effect of anodal tDCS is not thoroughly studied, and the heterogeneous profile of stroke individuals with brain lesions would further complicate the stimulation outcomes. This study aimed to investigate the functional changes in sensorimotor areas induced by anodal tDCS and whether individual electric field could predict the functional outcomes. Twenty-five chronic stroke survivors were recruited and divided into tDCS group (n = 12) and sham group (n = 13). Increased functional connectivity (FC) within the surrounding areas of ipsilesional primary motor cortex (M1) was only observed after anodal tDCS. Averaged FC among the ipsilesional sensorimotor regions was observed to be increased after anodal tDCS (t(11) = 2.57, p = 0.026), but not after sham tDCS (t(12) = 0.69, p = 0.50). Partial least square analysis identified positive correlations between electric field (EF) strength normal to the ipsilesional M1 surface and individual FC changes in tDCS group (r = 0.84, p < 0.001) but not in sham group (r = 0.21, p = 0.5). Our results indicated anodal tDCS facilitates the FC within the ipsilesional sensorimotor network in chronic stroke subjects, and individual electric field predicts the functional outcomes.
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Affiliation(s)
- Kai Yuan
- Department of Biomedical Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Chun-Hang Eden Ti
- Department of Biomedical Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Xin Wang
- Department of Biomedical Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Cheng Chen
- Department of Biomedical Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Cathy Choi-Yin Lau
- Department of Biomedical Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Winnie Chiu-Wing Chu
- Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Raymond Kai-Yu Tong
- Department of Biomedical Engineering, Faculty of Engineering, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China.
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Shaw P, Vanraes P, Kumar N, Bogaerts A. Possible Synergies of Nanomaterial-Assisted Tissue Regeneration in Plasma Medicine: Mechanisms and Safety Concerns. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3397. [PMID: 36234523 PMCID: PMC9565759 DOI: 10.3390/nano12193397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
Cold atmospheric plasma and nanomedicine originally emerged as individual domains, but are increasingly applied in combination with each other. Most research is performed in the context of cancer treatment, with only little focus yet on the possible synergies. Many questions remain on the potential of this promising hybrid technology, particularly regarding regenerative medicine and tissue engineering. In this perspective article, we therefore start from the fundamental mechanisms in the individual technologies, in order to envision possible synergies for wound healing and tissue recovery, as well as research strategies to discover and optimize them. Among these strategies, we demonstrate how cold plasmas and nanomaterials can enhance each other's strengths and overcome each other's limitations. The parallels with cancer research, biotechnology and plasma surface modification further serve as inspiration for the envisioned synergies in tissue regeneration. The discovery and optimization of synergies may also be realized based on a profound understanding of the underlying redox- and field-related biological processes. Finally, we emphasize the toxicity concerns in plasma and nanomedicine, which may be partly remediated by their combination, but also partly amplified. A widespread use of standardized protocols and materials is therefore strongly recommended, to ensure both a fast and safe clinical implementation.
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Affiliation(s)
- Priyanka Shaw
- Research Group PLASMANT, Department of Chemistry, University of Antwerp, 2610 Antwerp, Belgium
| | - Patrick Vanraes
- Research Group PLASMANT, Department of Chemistry, University of Antwerp, 2610 Antwerp, Belgium
| | - Naresh Kumar
- Department of Medical Devices, National Institute of Pharmaceutical Education and Research, Guwahati 781125, Assam, India
| | - Annemie Bogaerts
- Research Group PLASMANT, Department of Chemistry, University of Antwerp, 2610 Antwerp, Belgium
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12
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Simula S, Daoud M, Ruffini G, Biagi MC, Bénar CG, Benquet P, Wendling F, Bartolomei F. Transcranial current stimulation in epilepsy: A systematic review of the fundamental and clinical aspects. Front Neurosci 2022; 16:909421. [PMID: 36090277 PMCID: PMC9453675 DOI: 10.3389/fnins.2022.909421] [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: 03/31/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose Transcranial electrical current stimulation (tES or tCS, as it is sometimes referred to) has been proposed as non-invasive therapy for pharmacoresistant epilepsy. This technique, which includes direct current (tDCS) and alternating current (tACS) stimulation involves the application of weak currents across the cortex to change cortical excitability. Although clinical trials have demonstrated the therapeutic efficacy of tES, its specific effects on epileptic brain activity are poorly understood. We sought to summarize the clinical and fundamental effects underlying the application of tES in epilepsy. Methods A systematic review was performed in accordance with the PRISMA guidelines. A database search was performed in PUBMED, MEDLINE, Web of Science and Cochrane CENTRAL for articles corresponding to the keywords “epilepsy AND (transcranial current stimulation OR transcranial electrical stimulation)”. Results A total of 56 studies were included in this review. Through these records, we show that tDCS and tACS epileptic patients are safe and clinically relevant techniques for epilepsy. Recent articles reported changes of functional connectivity in epileptic patients after tDCS. We argue that tDCS may act by affecting brain networks, rather than simply modifying local activity in the targeted area. To explain the mechanisms of tES, various cellular effects have been identified. Among them, reduced cell loss, mossy fiber sprouting, and hippocampal BDNF protein levels. Brain modeling and human studies highlight the influence of individual brain anatomy and physiology on the electric field distribution. Computational models may optimize the stimulation parameters and bring new therapeutic perspectives. Conclusion Both tDCS and tACS are promising techniques for epilepsy patients. Although the clinical effects of tDCS have been repeatedly assessed, only one clinical trial has involved a consistent number of epileptic patients and little knowledge is present about the clinical outcome of tACS. To fill this gap, multicenter studies on tES in epileptic patients are needed involving novel methods such as personalized stimulation protocols based on computational modeling. Furthermore, there is a need for more in vivo studies replicating the tES parameters applied in patients. Finally, there is a lack of clinical studies investigating changes in intracranial epileptiform discharges during tES application, which could clarify the nature of tES-related local and network dynamics in epilepsy.
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Affiliation(s)
- Sara Simula
- Aix Marseille Univ, INSERM, INS, Int Neurosci Syst, Marseille, France
| | - Maëva Daoud
- Aix Marseille Univ, INSERM, INS, Int Neurosci Syst, Marseille, France
| | | | | | | | | | | | - Fabrice Bartolomei
- Aix Marseille Univ, INSERM, INS, Int Neurosci Syst, Marseille, France
- APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, Marseille, France
- *Correspondence: Fabrice Bartolomei
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13
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Beumer S, Boon P, Klooster DCW, van Ee R, Carrette E, Paulides MM, Mestrom RMC. Personalized tDCS for Focal Epilepsy—A Narrative Review: A Data-Driven Workflow Based on Imaging and EEG Data. Brain Sci 2022; 12:brainsci12050610. [PMID: 35624997 PMCID: PMC9139054 DOI: 10.3390/brainsci12050610] [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: 04/08/2022] [Revised: 05/03/2022] [Accepted: 05/05/2022] [Indexed: 02/01/2023] Open
Abstract
Conventional transcranial electric stimulation(tES) using standard anatomical positions for the electrodes and standard stimulation currents is frequently not sufficiently selective in targeting and reaching specific brain locations, leading to suboptimal application of electric fields. Recent advancements in in vivo electric field characterization may enable clinical researchers to derive better relationships between the electric field strength and the clinical results. Subject-specific electric field simulations could lead to improved electrode placement and more efficient treatments. Through this narrative review, we present a processing workflow to personalize tES for focal epilepsy, for which there is a clear cortical target to stimulate. The workflow utilizes clinical imaging and electroencephalography data and enables us to relate the simulated fields to clinical outcomes. We review and analyze the relevant literature for the processing steps in the workflow, which are the following: tissue segmentation, source localization, and stimulation optimization. In addition, we identify shortcomings and ongoing trends with regard to, for example, segmentation quality and tissue conductivity measurements. The presented processing steps result in personalized tES based on metrics like focality and field strength, which allow for correlation with clinical outcomes.
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Affiliation(s)
- Steven Beumer
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Correspondence:
| | - Paul Boon
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Neurology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Debby C. W. Klooster
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Neurology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Raymond van Ee
- Philips Research Eindhoven, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands;
| | - Evelien Carrette
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Neurology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Maarten M. Paulides
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
- Department of Radiation Oncology, Erasmus Medical Center Cancer Institute, Burgemeester Oudlaan 50, 3062 PA Rotterdam, The Netherlands
| | - Rob M. C. Mestrom
- Department of Electrical Engineering, University of Technology Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; (P.B.); (D.C.W.K.); (E.C.); (M.M.P.); (R.M.C.M.)
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Transcranial direct current stimulation (tDCS) effects on attention enhancement: A preliminary event related potential (ERP) study. CURRENT PSYCHOLOGY 2021. [DOI: 10.1007/s12144-021-02190-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Bhalerao GV, Sreeraj VS, Bose A, Narayanaswamy JC, Venkatasubramanian G. Comparison of electric field modeling pipelines for transcranial direct current stimulation. Neurophysiol Clin 2021; 51:303-318. [PMID: 34023189 DOI: 10.1016/j.neucli.2021.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/03/2021] [Accepted: 05/03/2021] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES Electric field modeling utilizes structural brain magnetic resonance images (MRI) to model the electric field induced by non-invasive transcranial direct current stimulation (tDCS) in a given individual. Electric field modeling is being integrated with clinical outcomes to improve understanding of inter-individual variability in tDCS effects and to optimize tDCS parameters, thereby enhancing the predictability of clinical effects. The successful integration of modeling in clinical use will primarily be driven by choice of tools and procedures implemented in computational modeling. Thus, the electric field predictions from different modeling pipelines need to be investigated to ensure the validity and reproducibility of tDCS modeling results across clinical or translational studies. METHODS We used T1w structural MRI from 32 healthy volunteer subjects and modeled the electric field distribution for a fronto-temporal tDCS montage. For five different computational modeling pipelines, we quantitatively compared brain tissue segmentation and electric field predicted in whole-brain, brain tissues and target brain regions between the modeling pipelines. RESULTS Our comparisons at various levels did not reveal any systematic trend with regards to similarity or dissimilarity of electric field predicted in brain tissues and target brain regions. The inconsistent trends in the predicted electric field indicate variation in the procedures, routines and algorithms used within and across the modeling pipelines. CONCLUSION Our results suggest that studies integrating electric field modeling and clinical outcomes of tDCS will highly depend upon the choice of the modeling pipelines and procedures. We propose that using these pipelines for further research and clinical applications should be subject to careful consideration, and indicate general recommendations.
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Affiliation(s)
- Gaurav V Bhalerao
- Department of Psychiatry, National Institute of Mental Health and Neuroscience (NIMHANS), Bengaluru 560029, India.
| | - Vanteemar S Sreeraj
- Department of Psychiatry, National Institute of Mental Health and Neuroscience (NIMHANS), Bengaluru 560029, India
| | - Anushree Bose
- Department of Psychiatry, National Institute of Mental Health and Neuroscience (NIMHANS), Bengaluru 560029, India
| | - Janardhanan C Narayanaswamy
- Department of Psychiatry, National Institute of Mental Health and Neuroscience (NIMHANS), Bengaluru 560029, India
| | - Ganesan Venkatasubramanian
- Department of Psychiatry, National Institute of Mental Health and Neuroscience (NIMHANS), Bengaluru 560029, India
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16
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Beliaeva V, Savvateev I, Zerbi V, Polania R. Toward integrative approaches to study the causal role of neural oscillations via transcranial electrical stimulation. Nat Commun 2021; 12:2243. [PMID: 33854049 PMCID: PMC8047004 DOI: 10.1038/s41467-021-22468-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/15/2021] [Indexed: 11/12/2022] Open
Abstract
Diverse transcranial electrical stimulation (tES) techniques have recently been developed to elucidate the role of neural oscillations, but critically, it remains questionable whether neural entrainment genuinely occurs and is causally related to the resulting behavior. Here, we provide a perspective on an emerging integrative research program across systems, species, theoretical and experimental frameworks to elucidate the potential of tES to induce neural entrainment. We argue that such an integrative agenda is a requirement to establish tES as a tool to test the causal role of neural oscillations and highlight critical issues that should be considered when adopting a translational approach.
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Affiliation(s)
- Valeriia Beliaeva
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
- Neuroscience Center Zurich, Switzerland, Zurich, Switzerland.
| | - Iurii Savvateev
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, Switzerland, Zurich, Switzerland
| | - Valerio Zerbi
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, Switzerland, Zurich, Switzerland
| | - Rafael Polania
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
- Neuroscience Center Zurich, Switzerland, Zurich, Switzerland.
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17
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Non-invasive cortical stimulation: Transcranial direct current stimulation (tDCS). INTERNATIONAL REVIEW OF NEUROBIOLOGY 2021; 159:1-22. [PMID: 34446242 DOI: 10.1016/bs.irn.2021.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a re-emerging non-invasive brain stimulation technique that has been used in animal models and human trials aimed to elucidate neurophysiology and behavior interactions. It delivers subthreshold electrical currents to neuronal populations that shift resting membrane potential either toward depolarization or hyperpolarization, depending on stimulation parameters and neuronal orientation in relation to the induced electric field (EF). Although the resulting cerebral EFs are not strong enough to induce action potentials, spontaneous neuronal firing in response to inputs from other brain areas is influenced by tDCS. Additionally, tDCS induces plastic synaptic changes resembling long-term potentiation (LTP) or long-term depression (LTD) that outlast the period of stimulation. Such properties place tDCS as an appealing intervention for the treatment of diverse neuropsychiatric disorders. Although findings of clinical trials are preliminary for most studied conditions, there is already convincing evidence regarding its efficacy for unipolar depression. The main advantages of tDCS are the absence of serious or intolerable side effects and the portability of the devices, which might lead in the future to home-use applications and improved patient care. This chapter provides an up-to-date overview of a number tDCS relevant topics such as mechanisms of action, contemporary applications and safety. Furthermore, we propose ways to further develop tDCS research.
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18
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Ruffini G, Salvador R, Tadayon E, Sanchez-Todo R, Pascual-Leone A, Santarnecchi E. Realistic modeling of mesoscopic ephaptic coupling in the human brain. PLoS Comput Biol 2020; 16:e1007923. [PMID: 32479496 PMCID: PMC7289436 DOI: 10.1371/journal.pcbi.1007923] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 06/11/2020] [Accepted: 05/01/2020] [Indexed: 11/29/2022] Open
Abstract
Several decades of research suggest that weak electric fields may influence neural processing, including those induced by neuronal activity and proposed as a substrate for a potential new cellular communication system, i.e., ephaptic transmission. Here we aim to model mesoscopic ephaptic activity in the human brain and explore its trajectory during aging by characterizing the electric field generated by cortical dipoles using realistic finite element modeling. Extrapolating from electrophysiological measurements, we first observe that modeled endogenous field magnitudes are comparable to those in measurements of weak but functionally relevant self-generated fields and to those produced by noninvasive transcranial brain stimulation, and therefore possibly able to modulate neuronal activity. Then, to evaluate the role of these fields in the human cortex in large MRI databases, we adapt an interaction approximation that considers the relative orientation of neuron and field to estimate the membrane potential perturbation in pyramidal cells. We use this approximation to define a simplified metric (EMOD1) that weights dipole coupling as a function of distance and relative orientation between emitter and receiver and evaluate it in a sample of 401 realistic human brain models from healthy subjects aged 16-83. Results reveal that ephaptic coupling, in the simplified mesoscopic modeling approach used here, significantly decreases with age, with higher involvement of sensorimotor regions and medial brain structures. This study suggests that by providing the means for fast and direct interaction between neurons, ephaptic modulation may contribute to the complexity of human function for cognition and behavior, and its modification across the lifespan and in response to pathology.
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Affiliation(s)
- Giulio Ruffini
- Neuroelectrics Corporation, Cambridge, Massachusetts, United States of America
- Neuroelectrics Barcelona, Barcelona, Spain
- Starlab Barcelona, Barcelona, Spain
| | | | - Ehsan Tadayon
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | | | - Alvaro Pascual-Leone
- Hinda and Arthur Marcus Institute for Aging Research and Center for Memory Health, Hebrew SeniorLife, Boston, Massachusetts, United States of America
- Guttmann Brain Health Institut, Institut Guttmann, Universitat Autonoma Barcelona, Spain
- Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Emiliano Santarnecchi
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
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19
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Denoyer Y, Merlet I, Wendling F, Benquet P. Modelling acute and lasting effects of tDCS on epileptic activity. J Comput Neurosci 2020; 48:161-176. [DOI: 10.1007/s10827-020-00745-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 02/10/2020] [Accepted: 04/04/2020] [Indexed: 12/11/2022]
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20
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Modolo J, Hassan M, Wendling F, Benquet P. Decoding the circuitry of consciousness: From local microcircuits to brain-scale networks. Netw Neurosci 2020; 4:315-337. [PMID: 32537530 PMCID: PMC7286300 DOI: 10.1162/netn_a_00119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/09/2019] [Indexed: 01/25/2023] Open
Abstract
Identifying the physiological processes underlying the emergence and maintenance of consciousness is one of the most fundamental problems of neuroscience, with implications ranging from fundamental neuroscience to the treatment of patients with disorders of consciousness (DOCs). One major challenge is to understand how cortical circuits at drastically different spatial scales, from local networks to brain-scale networks, operate in concert to enable consciousness, and how those processes are impaired in DOC patients. In this review, we attempt to relate available neurophysiological and clinical data with existing theoretical models of consciousness, while linking the micro- and macrocircuit levels. First, we address the relationships between awareness and wakefulness on the one hand, and cortico-cortical and thalamo-cortical connectivity on the other hand. Second, we discuss the role of three main types of GABAergic interneurons in specific circuits responsible for the dynamical reorganization of functional networks. Third, we explore advances in the functional role of nested oscillations for neural synchronization and communication, emphasizing the importance of the balance between local (high-frequency) and distant (low-frequency) activity for efficient information processing. The clinical implications of these theoretical considerations are presented. We propose that such cellular-scale mechanisms could extend current theories of consciousness.
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Affiliation(s)
- Julien Modolo
- University of Rennes, INSERM, LTSI-U1099, Rennes, France
| | - Mahmoud Hassan
- University of Rennes, INSERM, LTSI-U1099, Rennes, France
| | | | - Pascal Benquet
- University of Rennes, INSERM, LTSI-U1099, Rennes, France
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21
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Frequency-dependent entrainment of spontaneous Ca transients in the dendritic tufts of CA1 pyramidal cells in rat hippocampal slice preparations by weak AC electric field. Brain Res Bull 2019; 153:202-213. [DOI: 10.1016/j.brainresbull.2019.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 07/12/2019] [Accepted: 08/12/2019] [Indexed: 11/20/2022]
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22
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Bland NS, Sale MV. Current challenges: the ups and downs of tACS. Exp Brain Res 2019; 237:3071-3088. [DOI: 10.1007/s00221-019-05666-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/09/2019] [Indexed: 02/08/2023]
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23
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Lefaucheur JP, Wendling F. Mechanisms of action of tDCS: A brief and practical overview. Neurophysiol Clin 2019; 49:269-275. [PMID: 31350060 DOI: 10.1016/j.neucli.2019.07.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 12/20/2022] Open
Affiliation(s)
- Jean-Pascal Lefaucheur
- Unité de neurophysiologie clinique, EA4391, Henri-Mondor Hospital, Paris-Est Créteil University,, 94000 Créteil, France.
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Editorial overview: Neuromodulation. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2018. [DOI: 10.1016/j.cobme.2018.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Ruffini G, Wendling F, Sanchez-Todo R, Santarnecchi E. Targeting brain networks with multichannel transcranial current stimulation (tCS). CURRENT OPINION IN BIOMEDICAL ENGINEERING 2018. [DOI: 10.1016/j.cobme.2018.11.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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