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Nair PS, Zadeh-Haghighi H, Simon C. Radical pair model for magnetic field effects on NMDA receptor activity. Sci Rep 2024; 14:3628. [PMID: 38351304 PMCID: PMC10864372 DOI: 10.1038/s41598-024-54343-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/12/2024] [Indexed: 02/16/2024] Open
Abstract
The N-methyl-D-aspartate receptor is a prominent player in brain development and functioning. Perturbations to its functioning through external stimuli like magnetic fields can potentially affect the brain in numerous ways. Various studies have shown that magnetic fields of varying strengths affect these receptors. We propose that the radical pair mechanism, a quantum mechanical process, could explain some of these field effects. Radicals of the form [Formula: see text], where R is a protein residue that can be Serine or Tyrosine, are considered for this study. The variation in the singlet fractional yield of the radical pairs, as a function of magnetic field strength, is calculated to understand how the magnetic field affects the products of the radical pair reactions. Based on the results, the radical pair mechanism is a likely candidate for explaining the magnetic field effects observed on the receptor activity. The model predicts changes in the behaviour of the system as magnetic field strength is varied and also predicts certain isotope effects. The results further suggest that similar effects on radical pairs could be a plausible explanation for various magnetic field effects within the brain.
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Affiliation(s)
- Parvathy S Nair
- Department of Physics, Indian Institute of Science Education and Research (IISER), Tirupati, Tirupati, Andhra Pradesh, 517507, India.
| | - Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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2
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Beros JL, King ES, Clarke D, Jaeschke-Angi L, Rodger J, Tang AD. Static magnetic stimulation induces structural plasticity at the axon initial segment of inhibitory cortical neurons. Sci Rep 2024; 14:1479. [PMID: 38233493 PMCID: PMC10794225 DOI: 10.1038/s41598-024-51845-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 01/10/2024] [Indexed: 01/19/2024] Open
Abstract
Static magnetic stimulation (SMS) is a form of non-invasive brain stimulation that alters neural activity and induces neural plasticity that outlasts the period of stimulation. This can modify corticospinal excitability or motor behaviours, suggesting that SMS may alter the intrinsic excitability of neurons. In mammalian neurons, the axon initial segment (AIS) is the site of action potential initiation and undergoes structural plasticity (changes in length and position from the soma) as a homeostatic mechanism to counteract chronic changes in neuronal activity. We investigated whether the chronic application of SMS (6 and 48 h, 0.5 T) induces structural AIS plasticity in postnatally derived primary cortical neurons. Following 6 h of SMS, we observed a shortening in mean AIS length compared to control, that persisted 24 h post stimulation. In contrast, 48 h of SMS induced an immediate distal shift that persisted 24 h post-stimulation. Pharmacological blockade of voltage gated L/T-type calcium channels during stimulation did not prevent SMS-induced AIS structural plasticity. Our findings provide the foundation to expand the use of chronic SMS as a non-invasive method to promote AIS plasticity.
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Affiliation(s)
- J L Beros
- School of Biological Sciences, The University of Western Australia, Crawley, 6009, Australia.
- The Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia.
| | - E S King
- The Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia
- School of Biomedical Sciences, The University of Western Australia, Crawley, 6009, Australia
| | - D Clarke
- Département de Neurosciences, Université de Montréal, Quebec, H3C 3J7, Canada
| | - L Jaeschke-Angi
- School of Biological Sciences, The University of Western Australia, Crawley, 6009, Australia
- The Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia
| | - J Rodger
- School of Biological Sciences, The University of Western Australia, Crawley, 6009, Australia
- The Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia
| | - A D Tang
- The Perron Institute for Neurological and Translational Science, Nedlands, 6009, Australia.
- School of Biomedical Sciences, The University of Western Australia, Crawley, 6009, Australia.
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3
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Watanabe T, Chen X, Yunoki K, Matsumoto T, Horinouchi T, Ito K, Ishida H, Sunagawa T, Mima T, Kirimoto H. Differential Effects of Transcranial Static Magnetic Stimulation Over Left and Right Dorsolateral Prefrontal Cortex on Brain Oscillatory Responses During a Working Memory Task. Neuroscience 2023; 517:50-60. [PMID: 36907432 DOI: 10.1016/j.neuroscience.2023.03.006] [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: 10/03/2022] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/13/2023]
Abstract
Transcranial static magnetic stimulation (tSMS) is known to influence behavioral and neural activities. However, although the left and right dorsolateral prefrontal cortex (DLPFC) are associated with different cognitive functions, there remains a lack of knowledge on a difference in the effects of tSMS on cognitive performance and related brain activity between left and right DLPFC stimulations. To address this knowledge gap, we examined how differently tSMS over the left and right DLPFC altered working memory performance and electroencephalographic oscillatory responses using a 2-back task, in which subjects monitor a sequence of stimuli and decide whether a presented stimulus matches the stimulus presented two trials previously. Fourteen healthy adults (five females) performed the 2-back task before, during (20 min after the start of stimulation), immediately after, and 15 min after three different stimulation conditions: tSMS over the left DLPFC, tSMS over the right DLPFC, and sham stimulation. Our preliminary results revealed that while tSMS over the left and right DLPFC impaired working memory performance to a similar extent, the impacts of tSMS on brain oscillatory responses were different between the left and right DLPFC stimulations. Specifically, tSMS over the left DLPFC increased the event-related synchronization in beta band whereas tSMS over the right DLPFC did not show such an effect. These findings support evidence that the left and right DLPFC play different roles in working memory and suggest that the neural mechanism underlying the impairment of working memory by tSMS can be different between left and right DLPFC stimulations.
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Affiliation(s)
- Tatsunori Watanabe
- Faculty of Health Sciences, Aomori University of Health and Welfare, Aomori, Japan; Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
| | - Xiaoxiao Chen
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; College of Physical Education and Sports Rehabilitation, Jinzhou Medical University, Jinzhou, China
| | - Keisuke Yunoki
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takuya Matsumoto
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Faculty of Health Sciences, Tokyo Kasei University, Saitama, Japan
| | - Takayuki Horinouchi
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kanami Ito
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Haruki Ishida
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Toru Sunagawa
- Department of Analysis and Control of Upper Extremity Function, Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Tatsuya Mima
- Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto, Japan
| | - Hikari Kirimoto
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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4
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de Labra C, Cudeiro J, Rivadulla C. Synergistic effects of applying static magnetic fields and diazepam to improve EEG abnormalities in the pilocarpine epilepsy rat model. Sci Rep 2023; 13:214. [PMID: 36604478 PMCID: PMC9816095 DOI: 10.1038/s41598-022-26870-z] [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: 11/16/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
The lithium-pilocarpine rat model is a well-known model of temporal epilepsy. Recently we found that transcranial static magnetic stimulation (tSMS) delay and reduce the signs of EEG in this model. We aim to test the effect of combining the therapeutic action of tSMS and diazepam, a drug used to treat status epilepticus. We induce epilepsy in 12 Sprague-Dawley rats. Animals were classified as "magnet" when a magnetic neodymium cylinder was placed over the skull or "control" when a stainless-steel replica was used. Diazepam was injected 60-min after the second doses of pilocarpine injection. We found a reduction in the number of spikes/minute for magnet condition compared with sham condition, reaching significance at 60 min after diazepam injection. The Root-Mean-Square shown a significant reduction in magnet animals compared with those receiving diazepam (Tukey's-test 30 and 60 min after diazepam injection, p < 0.01; 40 and 50 min after diazepam injection, p < 0.05). Furthermore, the power spectrum analysis shown a reduction in delta, theta, alpha and beta bands, on the diazepam + magnet animals compared to the diazepam + sham group. Analysis of high-frequency oscillations revealed an increased in the ripples due to pilocarpine being reduced by diazepam. Our results demonstrate that application of tSMS previously to diazepam potentiates the effect of the drug by reducing the electroencephalographic pattern associated with epileptiform discharges. We suggest a new synergistic cooperation between pharmacology and neuromodulation as a future treatment for epilepsy.
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Affiliation(s)
- Carmen de Labra
- NEUROcom, Centro Interdisciplinar de Química e Bioloxía (CICA), Universidade da Coruña, Rúa as Carballeiras, 15071, A Coruña, Spain. .,NEUROcom, Facultade de Enfermería e Podoloxía, Universidade da Coruña, Campus de Esteiro, Ferrol, Spain. .,Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, As Xubias, 15006, A Coruña, Spain.
| | - Javier Cudeiro
- grid.8073.c0000 0001 2176 8535NEUROcom, Centro Interdisciplinar de Química e Bioloxía (CICA), Universidade da Coruña, Rúa as Carballeiras, 15071 A Coruña, Spain ,grid.420359.90000 0000 9403 4738Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, As Xubias, 15006 A Coruña, Spain ,grid.8073.c0000 0001 2176 8535NEUROcom, Facultade de Ciencias da Saúde, Universidade da Coruña, Campus de Oza, A Coruña, Spain ,Centro de Estimulación Cerebral de Galicia, A Coruña, Spain
| | - Casto Rivadulla
- grid.8073.c0000 0001 2176 8535NEUROcom, Centro Interdisciplinar de Química e Bioloxía (CICA), Universidade da Coruña, Rúa as Carballeiras, 15071 A Coruña, Spain ,grid.420359.90000 0000 9403 4738Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, As Xubias, 15006 A Coruña, Spain ,grid.8073.c0000 0001 2176 8535NEUROcom, Facultade de Ciencias da Saúde, Universidade da Coruña, Campus de Oza, A Coruña, Spain
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Shibata S, Watanabe T, Matsumoto T, Yunoki K, Horinouchi T, Kirimoto H, Zhang J, Wang H, Wu J, Onishi H, Mima T. Triple tSMS system (“SHIN jiba”) for non-invasive deep brain stimulation: a validation study in healthy subjects. J Neuroeng Rehabil 2022; 19:129. [DOI: 10.1186/s12984-022-01110-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022] Open
Abstract
Abstract
Background
Transcranial static magnetic field stimulation (tSMS) using a small and strong neodymium (NdFeB) magnet can temporarily suppress brain functions below the magnet. It is a promising non-invasive brain stimulation modality because of its competitive advantages such as safety, simplicity, and low-cost. However, current tSMS is insufficient to effectively stimulate deep brain areas due to attenuation of the magnetic field with the distance from the magnet. The aim of this study was to develop a brand-new tSMS system for non-invasive deep brain stimulation.
Methods
We designed and fabricated a triple tSMS system with three cylindrical NdFeB magnets placed close to each other. We compared the strength of magnetic field produced by the triple tSMS system with that by the current tSMS. Furthermore, to confirm its function, we stimulated the primary motor area in 17 healthy subjects with the triple tSMS for 20 min and assessed the cortical excitability using the motor evoked potential (MEP) obtained by transcranial magnetic stimulation.
Results
Our triple tSMS system produced the magnetic field sufficient for neuromodulation up to 80 mm depth from the magnet surface, which was 30 mm deeper than the current tSMS system. In the stimulation experiment, the triple tSMS significantly reduced the MEP amplitude, demonstrating a successful inhibition of the M1 excitability in healthy subjects.
Conclusion
Our triple tSMS system has an ability to produce an effective magnetic field in deep areas and to modulate the brain functions. It can be used for non-invasive deep brain stimulation.
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Chen X, Watanabe T, Kubo N, Yunoki K, Matsumoto T, Kuwabara T, Sunagawa T, Date S, Mima T, Kirimoto H. Transient Modulation of Working Memory Performance and Event-Related Potentials by Transcranial Static Magnetic Field Stimulation over the Dorsolateral Prefrontal Cortex. Brain Sci 2021; 11:brainsci11060739. [PMID: 34199505 PMCID: PMC8228367 DOI: 10.3390/brainsci11060739] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/23/2021] [Accepted: 05/31/2021] [Indexed: 11/23/2022] Open
Abstract
Transcranial static magnetic field stimulation (tSMS) can modulate human cortical excitability and behavior. To better understand the neuromodulatory effect of tSMS, this study investigates whether tSMS applied over the left dorsolateral prefrontal cortex (DLPFC) modulates working memory (WM) performance and its associated event-related potentials (ERPs). Thirteen healthy participants received tSMS or sham stimulation over the left DLPFC for 26 min on different days. The participants performed a 2-back version of the n-back task before, during (20 min after the start of stimulation), immediately after, and 15 min after the stimulation. We examine reaction time for correct responses, d-prime reflecting WM performance, and the N2 and P3 components of ERPs. Our results show that there was no effect of tSMS on reaction time. The d-prime was reduced, and the N2 latency was prolonged immediately after tSMS. These findings indicate that tSMS over the left DLPFC affects WM performance and its associated electrophysiological signals, which can be considered an important step toward a greater understanding of tSMS and its use in studies of higher-order cognitive processes.
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Affiliation(s)
- Xiaoxiao Chen
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (X.C.); (N.K.); (K.Y.); (T.M.); (T.K.); (H.K.)
| | - Tatsunori Watanabe
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (X.C.); (N.K.); (K.Y.); (T.M.); (T.K.); (H.K.)
- Correspondence:
| | - Nami Kubo
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (X.C.); (N.K.); (K.Y.); (T.M.); (T.K.); (H.K.)
| | - Keisuke Yunoki
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (X.C.); (N.K.); (K.Y.); (T.M.); (T.K.); (H.K.)
| | - Takuya Matsumoto
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (X.C.); (N.K.); (K.Y.); (T.M.); (T.K.); (H.K.)
- Japan Society for the Promotion of Science, Tokyo 102-0083, Japan
| | - Takayuki Kuwabara
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (X.C.); (N.K.); (K.Y.); (T.M.); (T.K.); (H.K.)
| | - Toru Sunagawa
- Department of Analysis and Control of Upper Extremity Function, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (T.S.); (S.D.)
| | - Shota Date
- Department of Analysis and Control of Upper Extremity Function, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (T.S.); (S.D.)
| | - Tatsuya Mima
- Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto 603-8577, Japan;
| | - Hikari Kirimoto
- Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan; (X.C.); (N.K.); (K.Y.); (T.M.); (T.K.); (H.K.)
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7
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Takamatsu Y, Inoue T, Okamura M, Ikegami R, Maejima H. In vivo local transcranial static magnetic field stimulation alters motor behavior in normal rats. Neurosci Lett 2021; 753:135864. [PMID: 33812926 DOI: 10.1016/j.neulet.2021.135864] [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: 11/02/2020] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 11/18/2022]
Abstract
Transcranial static magnetic field stimulation (tSMS) has inhibitory neuromodulatory effects on the human brain. Most of the studies on static magnetic fields have been performed in vitro. To further understand the biological mechanisms of tSMS, we investigated the effects of in vivo tSMS on motor behavior in normal awake rats. The skull of a male Wistar rat was exposed and a polyethylene tube was attached to the skull using dental cement at the center of the motor cortex (n = 7) or the other cortex (n = 6). By attaching a cylindrical NdFeB neodymium magnet into the tube, in vivo tSMS (REAL) was performed. For SHAM, we applied a similar size non-magnetic stainless-steel cylinder. All rats received twice each SHAM and REAL stimulation every two days using a crossover design, and motor function was measured during the stimulation. Activity level and asymmetry of forelimb use were not affected, but less accurate movements in the horizontal ladder test were found in REAL stimulation of the motor cortex. This study shows that in vivo tSMS has inhibitory neuromodulatory effects on motor behavior depending on the stimulated region on the rat cortex.
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Affiliation(s)
- Yasuyuki Takamatsu
- Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Kita 12 Nishi 5, Kita-ku, Sapporo 060-0812, Japan.
| | - Takahiro Inoue
- Research Fellow of Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan; Graduate School of Health Sciences, Hokkaido University, Kita 12 Nishi 5, Kita-ku, Sapporo 060-0812, Japan
| | - Misato Okamura
- Graduate School of Health Sciences, Hokkaido University, Kita 12 Nishi 5, Kita-ku, Sapporo 060-0812, Japan
| | - Ryo Ikegami
- Graduate School of Health Sciences, Hokkaido University, Kita 12 Nishi 5, Kita-ku, Sapporo 060-0812, Japan
| | - Hiroshi Maejima
- Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Kita 12 Nishi 5, Kita-ku, Sapporo 060-0812, Japan
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Transcranial static magnetic stimulation over the motor cortex can facilitate the contralateral cortical excitability in human. Sci Rep 2021; 11:5370. [PMID: 33686102 PMCID: PMC7940605 DOI: 10.1038/s41598-021-84823-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 02/19/2021] [Indexed: 01/27/2023] Open
Abstract
Transcranial static magnetic stimulation (tSMS) has been focused as a new non-invasive brain stimulation, which can suppress the human cortical excitability just below the magnet. However, the non-regional effects of tSMS via brain network have been rarely studied so far. We investigated whether tSMS over the left primary motor cortex (M1) can facilitate the right M1 in healthy subjects, based on the hypothesis that the functional suppression of M1 can cause the paradoxical functional facilitation of the contralateral M1 via the reduction of interhemispheric inhibition (IHI) between the bilateral M1. This study was double-blind crossover trial. We measured the corticospinal excitability in both M1 and IHI from the left to right M1 by recording motor evoked potentials from first dorsal interosseous muscles using single-pulse and paired-pulse transcranial magnetic stimulation before and after the tSMS intervention for 30 min. We found that the corticospinal excitability of the left M1 decreased, while that of the right M1 increased after tSMS. Moreover, the evaluation of IHI revealed the reduced inhibition from the left to the right M1. Our findings provide new insights on the mechanistic understanding of neuromodulatory effects of tSMS in human.
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Low-Field Magnetic Stimulation Accelerates the Differentiation of Oligodendrocyte Precursor Cells via Non-canonical TGF-β Signaling Pathways. Mol Neurobiol 2020; 58:855-866. [PMID: 33037982 DOI: 10.1007/s12035-020-02157-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/30/2020] [Indexed: 01/17/2023]
Abstract
Demyelination and oligodendrocyte loss are characteristic changes in demyelinating disorders. Low-field magnetic stimulation (LFMS) is a novel transcranial neuromodulation technology that has shown promising therapeutic potential for a variety of neuropsychiatric conditions. The cellular and molecular mechanisms of magnetic stimulation remain unclear. Previous studies mainly focused on the effects of magnetic stimulation on neuronal cells. Here we aimed to examine the effects of a gamma frequency LFMS on the glial progenitor cells. We used rat central glia-4 (CG4) cell line as an in vitro model. CG4 is a bipotential glial progenitor cell line that can differentiate into either oligodendrocyte or type 2-astrocyte. The cells cultured in a defined differentiation media were exposed to a 40-Hz LFMS 20 min daily for five consecutive days. We found that LFMS transiently elevated the level of TGF-β1 in the culture media in the first 24 h after the treatment. In correlation with the TGF-β1 levels, the percentage of cells possessing complex branches and expressing the late oligodendrocyte progenitor marker O4 was increased, indicating the accelerated differentiation of CG4 cells towards oligodendrocyte in LFMS-treated cultures. LFMS increased phosphorylation of Akt and Erk1/2 proteins, but not SMAD2/3. TGF-β1 receptor I specific inhibitor LY 364947 partially suppressed the effects of LFMS on differentiation and on levels of pAkt and pErk1/2, indicating that LFMS enhances the differentiation of oligodendrocyte progenitor cells via activation of non-canonical TGF-β-Akt and TGF-β-Erk1/2 pathways but not the canonical SMAD pathway. The data from this study reveal a novel mechanism of magnetic stimulation as a potential therapy for demyelination disorders.
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Affiliation(s)
- Atsushi Nambu
- Division of System Neurophysiology, National Institute for Physiological Sciences, Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan.
| | - Ichiro Tsuda
- Chubu University Academy of Emerging Sciences, Kasugai, Aichi 487-8501, Japan
| | - Tatsuya Mima
- The Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto, 603-8577, Japan
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