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Maccora S, Sardo P, Giglia G, Torrente A, Di Stefano V, Brighina F. Transcranial alternating current stimulation can modulate the blink reflex excitability. Effects of a 10- and 20-Hz tACS session on the blink reflex recovery cycle in healthy subjects. Neurol Sci 2024:10.1007/s10072-024-07719-x. [PMID: 39096396 DOI: 10.1007/s10072-024-07719-x] [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: 03/18/2024] [Accepted: 07/26/2024] [Indexed: 08/05/2024]
Abstract
BACKGROUND The blink reflex excitability, assessed through paired electrical stimuli responses, has been modulated using traditional non-invasive neurostimulation techniques. Recently, transcranial Alternating Current Stimulation (tACS) emerged as a tool to modulate brain oscillations implicated in various motor, perceptual, and cognitive functions. This study aims to investigate the influence of 20-Hz and 10-Hz tACS sessions on the primary motor cortex and their impact on blink reflex excitability. MATERIALS AND METHODS Fifteen healthy volunteers underwent 10-min tACS sessions (intensity 1 mA) with active/reference electrodes placed over C4/Pz, delivering 20-Hz, 10-Hz, and sham stimulation. The blink reflex recovery cycle (BRrc) was assessed using the R2 amplitude ratio at various interstimulus intervals (ISIs) before (T0), immediately after (T1), and 30 min post-tACS (T2). RESULTS Both 10-Hz and 20-Hz tACS sessions significantly increased R2 ratio at T1 (10-Hz: p = 0.02; 20-Hz: p < 0.001) and T2 (10-Hz: p = 0.01; 20-Hz: p < 0.001) compared to baseline (T0). Notably, 20-Hz tACS induced a significantly greater increase in blink reflex excitability compared to sham at both T1 (p = 0.04) and T2 (p < 0.001). CONCLUSION This study demonstrates the modulatory effect of tACS on trigemino-facial reflex circuits, with a lasting impact on BRrc. Beta-band frequency tACS exhibited a more pronounced effect than alpha-band frequency, highlighting the influential role of beta-band oscillations in the motor cortex on blink reflex excitability modulation.
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Affiliation(s)
- Simona Maccora
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BIND), University of Palermo, Palermo, Sicily, Italy.
- ARNAS Civico, Di Cristina, Via del Vespro 143, 90129, Benfratelli, Palermo, Italy.
| | - Pierangelo Sardo
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BIND), University of Palermo, Palermo, Sicily, Italy
| | - Giuseppe Giglia
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BIND), University of Palermo, Palermo, Sicily, Italy
| | - Angelo Torrente
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BIND), University of Palermo, Palermo, Sicily, Italy
| | - Vincenzo Di Stefano
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BIND), University of Palermo, Palermo, Sicily, Italy
| | - Filippo Brighina
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BIND), University of Palermo, Palermo, Sicily, Italy
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Lian Y, Cheng X, Chen Q, Huang L, Xie L, Wang W, Ni J, Chen X. Case report: Beneficial effects of visual cortex tDCS stimulation combined with visual training in patients with visual field defects. Front Neurol 2024; 15:1344348. [PMID: 38327623 PMCID: PMC10847570 DOI: 10.3389/fneur.2024.1344348] [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: 11/25/2023] [Accepted: 01/10/2024] [Indexed: 02/09/2024] Open
Abstract
Background Visual field defect (VFD) refers to the phenomenon that the eye is unable to see a certain area within the normal range of vision, which may be caused by eye diseases, neurological diseases and other reasons. Transcranial direct current stimulation (tDCS) is expected to be an effective treatment for the recovery or partial recovery of VFD. This paper describes the potential for tDCS in combination with visual retraining strategies to have a positive impact on vision recovery, and the potential for neuroplasticity to play a key role in vision recovery. Methods This case report includes two patients. Patient 1 was diagnosed with a right occipital hemorrhage and homonymous hemianopia. Patient 2 had multiple facial fractures, a contusion of the right eye, and damage to the optic nerve of the right eye, which was diagnosed as a peripheral nerve injury (optic nerve injury). We administered a series of treatments to two patients, including transcranial direct current stimulation; visual field restoration rehabilitation: paracentric gaze training, upper and lower visual field training, VR rehabilitation, and perceptual training. One time per day, 5 days per week, total 6 weeks. Results After 6 weeks of visual rehabilitation and tDCS treatment, Patient 1 Humphrey visual field examination showed a significant improvement compared to the initial visit, with a reduction in the extent of visual field defects, increased visual acuity, and improvement in most visual functions. Patient 2 had an expanded visual field, improved visual sensitivity, and substantial improvement in visual function. Conclusion Our case reports support the feasibility and effectiveness of tDCS combined with visual rehabilitation training in the treatment of occipital stroke and optic nerve injury settings.
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Affiliation(s)
- Yanhua Lian
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Rehabilitation, Fuzhou Second Hospital, Fuzhou, China
| | - Xiaoping Cheng
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Qunlin Chen
- Department of Radiology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Libin Huang
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Lili Xie
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Wenzong Wang
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Jun Ni
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Xinyuan Chen
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Rehabilitation Medicine, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
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Guidetti M, Maria Bianchi A, Parazzini M, Maiorana N, Bonato M, Ferrara R, Libelli G, Montemagno K, Ferrucci R, Priori A, Bocci T. Monopolar tDCS might affect brainstem reflexes: A computational and neurophysiological study. Clin Neurophysiol 2023; 155:44-54. [PMID: 37690391 DOI: 10.1016/j.clinph.2023.08.011] [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: 06/06/2023] [Revised: 08/04/2023] [Accepted: 08/12/2023] [Indexed: 09/12/2023]
Abstract
OBJECTIVE To assess whether monopolar multi-electrode transcranial direct current stimulation (tDCS) montages might selectively affect deep brain structures through computational predictions and neurophysiological assessment. METHODS Electric field distribution in deep brain structures (i.e., thalamus and midbrain) were estimated through computational models simulating tDCS with two monopolar and two monopolar multi-electrode montages. Monopolar multi-electrode tDCS was then applied to healthy subject, and effects on pontine and medullary circuitries was evaluated studying changes in blink reflex (BR) and masseter inhibitory reflex (MIR). RESULTS Computational results suggest that tDCS with monopolar multi-electrode montages might induce electric field intensities in deep brain structure comparable to those in grey matter, while neurophysiological results disclosed that BR and MIR were selectively modulated by tDCS only when cathode was placed over the right deltoid. CONCLUSIONS Multi-electrode tDCS (anodes over motor cortices, cathode over right deltoid) could induce significant electric fields in the thalamus and midbrain, and selectively affect brainstem neural circuits. SIGNIFICANCE Multi-electrode tDCS (anodes over motor cortices, cathode over right deltoid) might be further explored to affect brainstem activity, also in the context of non-invasive deep brain stimulation.
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Affiliation(s)
- Matteo Guidetti
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy
| | - Anna Maria Bianchi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy
| | - Marta Parazzini
- Institute of Electronics, Computer and Telecommunication Engineering (IEIIT), CNR, 20133 Milan, Italy
| | - Natale Maiorana
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Marta Bonato
- Institute of Electronics, Computer and Telecommunication Engineering (IEIIT), CNR, 20133 Milan, Italy
| | - Rosanna Ferrara
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Giorgia Libelli
- Neurology Unit, Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43126 Parma, Italy
| | - Kora Montemagno
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Roberta Ferrucci
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Clinical Neurology Unit, "Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo", Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Alberto Priori
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Clinical Neurology Unit, "Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo", Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Tommaso Bocci
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Clinical Neurology Unit, "Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo", Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy.
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Wong R, Sesa-Ashton G, Datta S, McCarthy B, Henderson LA, Dawood T, Macefield VG. The role of the dorsolateral prefrontal cortex in control of skin sympathetic nerve activity in humans. Cereb Cortex 2023; 33:8265-8272. [PMID: 37143172 PMCID: PMC10558060 DOI: 10.1093/cercor/bhad112] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 05/06/2023] Open
Abstract
The dorsolateral prefrontal cortex (dlPFC) is primarily involved in higher order executive functions, with there being evidence of lateralization. Brain imaging studies have revealed its link to the generation of skin sympathetic nerve activity (SSNA), which is elevated in states of emotional arousal or anxiety. However, no studies have directly explored dlPFC influences on SSNA. Transcranial alternating current stimulation (-2 to 2 mA, 0.08 Hz, 100 cycles) was applied between the left or right dlPFC and nasion via surface electrodes. Spontaneous bursts of SSNA were recorded from the common peroneal nerve via a tungsten microelectrode in 21 healthy participants. The modulation index was calculated for each stimulation paradigm by constructing cross-correlation histograms between SSNA and the sinusoidal stimulus. Stimulation of the dlPFC caused significant modulation of SSNA, but there was no significant difference in the median modulation index across sides. Stimulation also caused cyclic modulation of skin blood flow and sweat release. We have shown for the first time that stimulation of the dlPFC causes modulation of SSNA, also reflected in the effector-organ responses. This supports a role for the dlPFC in the control of SSNA, which likely contributes to the ability of emotions to bring about cutaneous vasoconstriction and sweat release.
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Affiliation(s)
- Rebecca Wong
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Baker Department of Cardiometabolic Health, The University of Melbourne, VIC, Australia
| | | | - Sudipta Datta
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Baker Department of Cardiometabolic Health, The University of Melbourne, VIC, Australia
| | - Brendan McCarthy
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Baker Department of Cardiometabolic Health, The University of Melbourne, VIC, Australia
| | - Luke A Henderson
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, The University of Sydney, NSW, Australia
| | - Tye Dawood
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Baker Department of Cardiometabolic Health, The University of Melbourne, VIC, Australia
| | - Vaughan G Macefield
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Baker Department of Cardiometabolic Health, The University of Melbourne, VIC, Australia
- Department of Anatomy and Physiology, The University of Melbourne, VIC, Australia
- Department of Neuroscience, Central Clinical School, Monash University, VIC, Australia
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5
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Kumru H, Kofler M, Valls-Sole J. Modulation of brainstem reflexes induced by non-invasive brain stimulation: is there a future? Neural Regen Res 2021; 16:2004-2005. [PMID: 33642379 PMCID: PMC8343321 DOI: 10.4103/1673-5374.308083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Hatice Kumru
- Institut Guttmann, Institut Universitari de Neurorehabilitació adscrit a la UAB, 089M6 Badalona - Barcelona; Univ Autonoma de Barcelona, 08M93 Bellaterra (Cerdanyola del Vallès); Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain
| | - Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria
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Bikson M, Dmochowski J. What it means to go deep with non-invasive brain stimulation. Clin Neurophysiol 2019; 131:752-754. [PMID: 31917081 DOI: 10.1016/j.clinph.2019.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 12/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States.
| | - Jacek Dmochowski
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States
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7
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Imamura Y, Shinozaki T, Okada-Ogawa A, Noma N, Shinoda M, Iwata K, Wada A, Abe O, Wang K, Svensson P. An updated review on pathophysiology and management of burning mouth syndrome with endocrinological, psychological and neuropathic perspectives. J Oral Rehabil 2019; 46:574-587. [PMID: 30892737 DOI: 10.1111/joor.12795] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/19/2019] [Accepted: 03/12/2019] [Indexed: 12/17/2022]
Abstract
Burning mouth syndrome (BMS) is a chronic oro-facial pain disorder of unknown cause. It is more common in peri- and post-menopausal women, and sex hormone dysregulation is believed to be an important causative factor. Psychosocial events often trigger or exacerbate symptoms, and persons with BMS appear to be predisposed towards anxiety and depression. Atrophy of small nerve fibres in the tongue epithelium has been reported, and potential neuropathic mechanisms for BMS are now widely investigated. Historically, BMS was thought to comprise endocrinological, psychosocial and neuropathic components. Neuroprotective steroids and glial cell line-derived neurotrophic factor family ligands may have pivotal roles in the peripheral mechanisms associated with atrophy of small nerve fibres. Denervation of chorda tympani nerve fibres that innervate fungiform buds leads to alternative trigeminal innervation, which results in dysgeusia and burning pain when eating hot foods. With regard to the central mechanism of BMS, depletion of neuroprotective steroids alters the brain network-related mood and pain modulation. Peripheral mechanistic studies support the use of topical clonazepam and capsaicin for the management of BMS, and some evidence supports the use of cognitive behavioural therapy. Hormone replacement therapy may address the causes of BMS, although adverse effects prevent its use as a first-line treatment. Selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) may have important benefits, and well-designed controlled studies are expected. Other treatment options to be investigated include brain stimulation and TSPO (translocator protein 18 kDa) ligands.
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Affiliation(s)
- Yoshiki Imamura
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Takahiro Shinozaki
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Akiko Okada-Ogawa
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Noboru Noma
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Masahiro Shinoda
- Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan.,Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Koichi Iwata
- Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan.,Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Akihiko Wada
- Department of Radiology, Faculty of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Kelun Wang
- Department of Health Science and Technology, Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark
| | - Peter Svensson
- Department of Dentistry and Oral Health, Section for Orofacial Pain and Jaw Function, Aarhus University, Aarhus, Denmark
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Karabanov AN, Saturnino GB, Thielscher A, Siebner HR. Can Transcranial Electrical Stimulation Localize Brain Function? Front Psychol 2019; 10:213. [PMID: 30837911 PMCID: PMC6389710 DOI: 10.3389/fpsyg.2019.00213] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/22/2019] [Indexed: 11/13/2022] Open
Abstract
Transcranial electrical stimulation (TES) uses constant (TDCS) or alternating currents (TACS) to modulate brain activity. Most TES studies apply low-intensity currents through scalp electrodes (≤2 mA) using bipolar electrode arrangements, producing weak electrical fields in the brain (<1 V/m). Low-intensity TES has been employed in humans to induce changes in task performance during or after stimulation. In analogy to focal transcranial magnetic stimulation, TES-induced behavioral effects have often been taken as evidence for a causal involvement of the brain region underlying one of the two stimulation electrodes, often referred to as the active electrode. Here, we critically review the utility of bipolar low-intensity TES to localize human brain function. We summarize physiological substrates that constitute peripheral targets for TES and may mediate subliminal or overtly perceived peripheral stimulation during TES. We argue that peripheral co-stimulation may contribute to the behavioral effects of TES and should be controlled for by "sham" TES. We discuss biophysical properties of TES, which need to be considered, if one wishes to make realistic assumptions about which brain regions were preferentially targeted by TES. Using results from electric field calculations, we evaluate the validity of different strategies that have been used for selective spatial targeting. Finally, we comment on the challenge of adjusting the dose of TES considering dose-response relationships between the weak tissue currents and the physiological effects in targeted cortical areas. These considerations call for caution when attributing behavioral effects during or after low-intensity TES studies to a specific brain region and may facilitate the selection of best practices for future TES studies.
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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
| | - Guilherme Bicalho Saturnino
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Electrical Engineering, Technical University of Denmark, Copenhagen, Denmark
| | - Axel Thielscher
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Electrical Engineering, Technical University of Denmark, Copenhagen, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
- Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
- Institute for Clinical Medicine, Faculty of Health Sciences and Medicine, University of Copenhagen, Copenhagen, Denmark
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Kumru H, Kofler M, Valls-Sole J, Vidal J. Brainstem reflex excitability after high-frequency repetitive transcranial magnetic stimulation in healthy and spinal cord injury subjects. Brain Res Bull 2019; 147:86-91. [PMID: 30769128 DOI: 10.1016/j.brainresbull.2019.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/18/2019] [Accepted: 02/06/2019] [Indexed: 01/04/2023]
Abstract
BACKGROUND The excitability of brainstem interneuronal circuits is partly under control from descending inputs. Since high frequency repetitive transcranial magnetic stimulation (rTMS) modulates cortical output, we hypothesized that it will also modulate brainstem functions. Such modulation may be different in healthy subjects than in subjects with spinal cord injury (SCI), submitted to an altered integration of body afferent inputs. METHODS In this randomized, double-blind, sham-controlled trial, we recruited 22 subjects with SCI assigned to either real (n = 11) or sham (n = 11) rTMS and nine healthy subjects, who served as control group, receiving both real (at 20 Hz, with double cone coil over vertex) and sham rTMS separated by at least one week. We recorded the blink reflex (BR) to supraorbital nerve (SON) electrical stimulation and its modification by another conditioning SON, to study the BR excitability recovery (BRER), or a prepulse electrical stimulus to the right index finger, to study the BR inhibition by prepulse (BRIP). Subjects were examined immediately before and after either sham or real rTMS. RESULTS Real but not sham rTMS significantly reduced the area of the BR R2 response in both SCI and healthy subjects. There were no changes in BRER and BRIP. CONCLUSION rTMS over the vertex modulates brainstem reflexes with no significant differences between SCI and healthy subjects.
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Affiliation(s)
- Hatice Kumru
- Institut Guttmann, Institut Universitari de Neurorehabilitació adscrit a la UAB, 089M6, Badalona, Barcelona, Spain; Univ Autonoma de Barcelona, 08M93, Bellaterra, Cerdanyola del Vallès, Spain; Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain.
| | - Markus Kofler
- Institut Guttmann, Institut Universitari de Neurorehabilitació adscrit a la UAB, 089M6, Badalona, Barcelona, Spain
| | | | - Joan Vidal
- Institut Guttmann, Institut Universitari de Neurorehabilitació adscrit a la UAB, 089M6, Badalona, Barcelona, Spain; Univ Autonoma de Barcelona, 08M93, Bellaterra, Cerdanyola del Vallès, Spain; Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain
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Gebodh N, Esmaeilpour Z, Adair D, Chelette K, Dmochowski J, Woods AJ, Kappenman ES, Parra LC, Bikson M. Inherent physiological artifacts in EEG during tDCS. Neuroimage 2018; 185:408-424. [PMID: 30321643 DOI: 10.1016/j.neuroimage.2018.10.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/10/2018] [Accepted: 10/08/2018] [Indexed: 12/30/2022] Open
Abstract
Online imaging and neuromodulation is invalid if stimulation distorts measurements beyond the point of accurate measurement. In theory, combining transcranial Direct Current Stimulation (tDCS) with electroencephalography (EEG) is compelling, as both use non-invasive electrodes and image-guided dose can be informed by the reciprocity principle. To distinguish real changes in EEG from stimulation artifacts, prior studies applied conventional signal processing techniques (e.g. high-pass filtering, ICA). Here, we address the assumptions underlying the suitability of these approaches. We distinguish physiological artifacts - defined as artifacts resulting from interactions between the stimulation induced voltage and the body and so inherent regardless of tDCS or EEG hardware performance - from methodology-related artifacts - arising from non-ideal experimental conditions or non-ideal stimulation and recording equipment performance. Critically, we identify inherent physiological artifacts which are present in all online EEG-tDCS: 1) cardiac distortion and 2) ocular motor distortion. In conjunction, non-inherent physiological artifacts which can be minimized in most experimental conditions include: 1) motion and 2) myogenic distortion. Artifact dynamics were analyzed for varying stimulation parameters (montage, polarity, current) and stimulation hardware. Together with concurrent physiological monitoring (ECG, respiration, ocular, EMG, head motion), and current flow modeling, each physiological artifact was explained by biological source-specific body impedance changes, leading to incremental changes in scalp DC voltage that are significantly larger than real neural signals. Because these artifacts modulate the DC voltage and scale with applied current, they are dose specific such that their contamination cannot be accounted for by conventional experimental controls (e.g. differing stimulation montage or current as a control). Moreover, because the EEG artifacts introduced by physiologic processes during tDCS are high dimensional (as indicated by Generalized Singular Value Decomposition- GSVD), non-stationary, and overlap highly with neurogenic frequencies, these artifacts cannot be easily removed with conventional signal processing techniques. Spatial filtering techniques (GSVD) suggest that the removal of physiological artifacts would significantly degrade signal integrity. Physiological artifacts, as defined here, would emerge only during tDCS, thus processing techniques typically applied to EEG in the absence of tDCS would not be suitable for artifact removal during tDCS. All concurrent EEG-tDCS must account for physiological artifacts that are a) present regardless of equipment used, and b) broadband and confound a broad range of experiments (e.g. oscillatory activity and event related potentials). Removal of these artifacts requires the recognition of their non-stationary, physiology-specific dynamics, and individualized nature. We present a broad taxonomy of artifacts (non/stimulation related), and suggest possible approaches and challenges to denoising online EEG-tDCS stimulation artifacts.
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Affiliation(s)
- Nigel Gebodh
- Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, NY, USA.
| | - Zeinab Esmaeilpour
- Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, NY, USA.
| | - Devin Adair
- Department of Psychology, The Graduate Center at City University of New York, New York, NY, USA.
| | | | - Jacek Dmochowski
- Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, NY, USA.
| | - Adam J Woods
- Center for Cognitive Aging and Memory, McKnight Brain Institute, Department of Clinical and Health Psychology, Department of Neuroscience, University of Florida, Gainesville, FL, USA.
| | | | - Lucas C Parra
- Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, NY, USA.
| | - Marom Bikson
- Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, NY, USA; Department of Psychology, The Graduate Center at City University of New York, New York, NY, USA.
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Shiozawa P, Soares A, Taiar I, Dias ÁM, Cordeiro Q. Transcranial direct current stimulation (tDCS): Are we losing energy? Epilepsy Behav 2017; 66:138-139. [PMID: 27979410 DOI: 10.1016/j.yebeh.2016.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 10/13/2016] [Accepted: 10/13/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Pedro Shiozawa
- Evidence-based Psychiatry Unit, Santa Casa Medical School, São Paulo, Brazil; Center for neuromodulation studies of the Federal University of Sao Paulo Medical School, Brazil.
| | - Amanda Soares
- Evidence-based Psychiatry Unit, Santa Casa Medical School, São Paulo, Brazil; Center for neuromodulation studies of the Federal University of Sao Paulo Medical School, Brazil
| | - Ivan Taiar
- Evidence-based Psychiatry Unit, Santa Casa Medical School, São Paulo, Brazil; Center for neuromodulation studies of the Federal University of Sao Paulo Medical School, Brazil
| | - Álvaro Machado Dias
- Clinical Neuroscience Lab of the Dept. of Psychiatry, Federal University of São Paulo, Brazil; Center for neuromodulation studies of the Federal University of Sao Paulo Medical School, Brazil
| | - Quirino Cordeiro
- Evidence-based Psychiatry Unit, Santa Casa Medical School, São Paulo, Brazil; Center for neuromodulation studies of the Federal University of Sao Paulo Medical School, Brazil
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