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Hsieh TH, Chu PC, Nguyen TXD, Kuo CW, Chang PK, Chen KHS, Liu HL. Neuromodulatory Responses Elicited by Intermittent versus Continuous Transcranial Focused Ultrasound Stimulation of the Motor Cortex in Rats. Int J Mol Sci 2024; 25:5687. [PMID: 38891875 PMCID: PMC11171676 DOI: 10.3390/ijms25115687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/09/2024] [Accepted: 05/17/2024] [Indexed: 06/21/2024] Open
Abstract
Transcranial focused ultrasound stimulation (tFUS) has emerged as a promising neuromodulation technique that delivers acoustic energy with high spatial resolution for inducing long-term potentiation (LTP)- or depression (LTD)-like plasticity. The variability in the primary effects of tFUS-induced plasticity could be due to different stimulation patterns, such as intermittent versus continuous, and is an aspect that requires further detailed exploration. In this study, we developed a platform to evaluate the neuromodulatory effects of intermittent and continuous tFUS on motor cortical plasticity before and after tFUS application. Three groups of rats were exposed to either intermittent, continuous, or sham tFUS. We analyzed the neuromodulatory effects on motor cortical excitability by examining changes in motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS). We also investigated the effects of different stimulation patterns on excitatory and inhibitory neural biomarkers, examining c-Fos and glutamic acid decarboxylase (GAD-65) expression using immunohistochemistry staining. Additionally, we evaluated the safety of tFUS by analyzing glial fibrillary acidic protein (GFAP) expression. The current results indicated that intermittent tFUS produced a facilitation effect on motor excitability, while continuous tFUS significantly inhibited motor excitability. Furthermore, neither tFUS approach caused injury to the stimulation sites in rats. Immunohistochemistry staining revealed increased c-Fos and decreased GAD-65 expression following intermittent tFUS. Conversely, continuous tFUS downregulated c-Fos and upregulated GAD-65 expression. In conclusion, our findings demonstrate that both intermittent and continuous tFUS effectively modulate cortical excitability. The neuromodulatory effects may result from the activation or deactivation of cortical neurons following tFUS intervention. These effects are considered safe and well-tolerated, highlighting the potential for using different patterns of tFUS in future clinical neuromodulatory applications.
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Affiliation(s)
- Tsung-Hsun Hsieh
- School of Physical Therapy, Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan 33302, Taiwan; (T.X.D.N.); (C.-W.K.); (P.-K.C.)
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan 33305, Taiwan
- Healthy Aging Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Po-Chun Chu
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan;
| | - Thi Xuan Dieu Nguyen
- School of Physical Therapy, Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan 33302, Taiwan; (T.X.D.N.); (C.-W.K.); (P.-K.C.)
| | - Chi-Wei Kuo
- School of Physical Therapy, Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan 33302, Taiwan; (T.X.D.N.); (C.-W.K.); (P.-K.C.)
| | - Pi-Kai Chang
- School of Physical Therapy, Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan 33302, Taiwan; (T.X.D.N.); (C.-W.K.); (P.-K.C.)
| | - Kai-Hsiang Stanley Chen
- Department of Neurology, National Taiwan University Hospital Hsinchu Branch, Hsinchu 300195, Taiwan
| | - Hao-Li Liu
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan;
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Izbicki P, Mendoza T, Zaman A, Stegemöller EL. Differences in motor inhibition in young and older musicians and non-musicians at rest. Front Aging Neurosci 2023; 15:1230865. [PMID: 37744390 PMCID: PMC10514489 DOI: 10.3389/fnagi.2023.1230865] [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: 05/29/2023] [Accepted: 08/04/2023] [Indexed: 09/26/2023] Open
Abstract
Introduction Older adults experience a decline in motor inhibition. These declines have been implicated in instrumental activities of daily living. However, studies have revealed that older musicians have behavioral and neurophysiological enhancements in various motor domains compared to non-musicians. This suggests that music training may delay the decline in motor inhibition with aging. Nevertheless, motor inhibition has not been studied in young or older musicians and non-musicians. Thus, the present study aimed to investigate the neurophysiological differences in motor inhibition in aging musicians and non-musicians. Methods A total of 19 healthy young adult musicians, 16 healthy young non-musicians, 13 healthy older adult musicians, and 16 healthy older adult non-musicians were recruited for the study. Transcranial magnetic stimulation single-pulse (SP) and short interval cortical inhibition (SICI) were performed at rest and then converted into inhibition percentage. Results We did not observe significant differences between young and older musicians and non-musicians in resting SP MEP. Older adults had lower resting SICI MEP than young adults. Older adults (36%) had a greater percentage of inhibition than young adults (16%). However, when controlling for background EMG activity, musicians had a lower inhibition percentage than non-musicians. Discussion The results revealed that, despite the greater use of spinal mechanisms, decreased SICI, and increased inhibition percentage in older adults, motor inhibitory circuitry remains intact and functional in both young and older musicians and non-musicians. Future studies will reveal whether there are differences in motor inhibition during movement in musicians across a person's lifespan.
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Affiliation(s)
- Patricia Izbicki
- Department of Kinesiology, Iowa State University, Ames, IA, United States
| | - Tessa Mendoza
- Department of Kinesiology, Iowa State University, Ames, IA, United States
| | - Andrew Zaman
- Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, United States
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Lee CW, Chu MC, Wu HF, Chung YJ, Hsieh TH, Chang CY, Lin YC, Lu TY, Chang CH, Chi H, Chang HS, Chen YF, Li CT, Lin HC. Different synaptic mechanisms of intermittent and continuous theta-burst stimulations in a severe foot-shock induced and treatment-resistant depression in a rat model. Exp Neurol 2023; 362:114338. [PMID: 36717014 DOI: 10.1016/j.expneurol.2023.114338] [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: 08/28/2022] [Revised: 01/04/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023]
Abstract
Treatment-resistant depression (TRD) is a condition wherein patients with depression fail to respond to antidepressant trials. A new form of repetitive transcranial magnetic stimulation (rTMS), called theta-burst stimulation (TBS), which includes intermittent theta-burst stimulation (iTBS) and continuous theta-burst stimulation (cTBS), is non-inferior to rTMS in TRD treatment. However, the mechanism of iTBS and cTBS underlying the treatment of TRD in the prefrontal cortex (PFC) remains unclear. Hence, we applied foot-shock stress as a traumatic event to develop a TRD rat model and investigated the different mechanisms of iTBS and cTBS. The iTBS and cTBS treatment were effective in depressive-like behavior and active coping behavior. The iTBS treatments improved impaired long-term potentiation and long-term depression (LTD), whereas the cTBS treatment only improved aberrant LTD. Moreover, the decrease in mature brain-derived neurotrophic factor (BDNF)-related protein levels were reversed by iTBS treatment. The decrease in proBDNF-related protein expression was improved by iTBS and cTBS treatment. Both iTBS and cTBS improved the decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and downregulation of mammalian target of the rapamycin (mTOR) signaling pathway. The iTBS produces both excitatory and inhibitory synaptic effects, and the cTBS only produces inhibitory synaptic effects in the PFC.
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Affiliation(s)
- Chi-Wei Lee
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ming-Chia Chu
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Han-Fang Wu
- Department of Optometry, Hsin-Sheng College of Medical Care and Management, Taoyuan, Taiwan
| | - Yueh-Jung Chung
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Tsung-Han Hsieh
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chieh-Yu Chang
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yen-Cheng Lin
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ting-Yi Lu
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ching-Hsiang Chang
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Hsiang Chi
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Hsun-Shuo Chang
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung
| | - Yih-Fung Chen
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung
| | - Cheng-Ta Li
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Division of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.
| | - Hui-Ching Lin
- Department and Institute of Physiology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institute, Taipei, Taiwan.
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Kuga K, Ozaki H, Fujiki M. Motor-evoked potentials after focal electrical stimulation predict drug-induced convulsion potentials in rats. Toxicol Mech Methods 2023; 33:123-130. [PMID: 35822219 DOI: 10.1080/15376516.2022.2101038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Drug-induced convulsions-often caused by the inhibition of GABA receptors and stimulation of glutamate receptors-are difficult to predict in animals. In this study, we attempted to detect the proconvulsant potential using motor-evoked potentials (MEPs) after focal electrical stimulation or upon using a functional observational battery (FOB). Pentylenetetrazole, kainic acid, and pilocarpine were used as convulsion-inducing drugs, and baclofen was used as a negative control. First, each compound was administered to male rats, and the FOB tests were performed. All drugs induced behavioral changes, but no commonality was found. Single electrical stimulation train MEPs were recorded under anesthesia for 60 min (at 5 min intervals) after administration of each drug. A dose-dependent increase in MEPs was observed for each convulsion-inducing drug. Moreover, paired electrical stimulation (conditioned and test) of the cerebral motor cortex was conducted with a 1-15 ms interstimulus interval (ISI), 10 min after administration of the drug. All convulsion-inducing drugs inhibited the short-interval intracortical inhibition (ISI: 3 ms), which may be associated with GABA. Intracortical facilitation (ISI: 11 ms), related to glutamate, was not enhanced by any drug but was inhibited by pilocarpine. Dose correlation was not found in short-interval intracortical inhibition or intracortical facilitation in any drugs. No changes in MEPs were observed after baclofen administration. These results suggest that it is possible to evaluate the convulsion potential and associated mechanisms using MEP, independent of the behavioral changes. The early identification of convulsion potential using this model will lead to more efficient drug development.
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Affiliation(s)
- Kazuhiro Kuga
- Drug Safety Research and Evaluation, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Harushige Ozaki
- Drug Safety Research and Evaluation, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Minoru Fujiki
- Department of Neurosurgery, School of Medicine, Oita University, Yufu City, Oita, Japan
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Weak Ultrasound Contributes to Neuromodulatory Effects in the Rat Motor Cortex. Int J Mol Sci 2023; 24:ijms24032578. [PMID: 36768901 PMCID: PMC9917173 DOI: 10.3390/ijms24032578] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Transcranial focused ultrasound (tFUS) is a novel neuromodulating technique. It has been demonstrated that the neuromodulatory effects can be induced by weak ultrasound exposure levels (spatial-peak temporal average intensity, ISPTA < 10 mW/cm2) in vitro. However, fewer studies have examined the use of weak tFUS to potentially induce long-lasting neuromodulatory responses in vivo. The purpose of this study was to determine the lower-bound threshold of tFUS stimulation for inducing neuromodulation in the motor cortex of rats. A total of 94 Sprague-Dawley rats were used. The sonication region aimed at the motor cortex under weak tFUS exposure (ISPTA of 0.338-12.15 mW/cm2). The neuromodulatory effects of tFUS on the motor cortex were evaluated by the changes in motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS). In addition to histology analysis, the in vitro cell culture was used to confirm the neuromodulatory mechanisms following tFUS stimulation. In the results, the dose-dependent inhibitory effects of tFUS were found, showing increased intensities of tFUS suppressed MEPs and lasted for 30 min. Weak tFUS significantly decreased the expression of excitatory neurons and increased the expression of inhibitory GABAergic neurons. The PIEZO-1 proteins of GABAergic neurons were found to involve in the inhibitory neuromodulation. In conclusion, we show the use of weak ultrasound to induce long-lasting neuromodulatory effects and explore the potential use of weak ultrasound for future clinical neuromodulatory applications.
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Jannati A, Oberman LM, Rotenberg A, Pascual-Leone A. Assessing the mechanisms of brain plasticity by transcranial magnetic stimulation. Neuropsychopharmacology 2023; 48:191-208. [PMID: 36198876 PMCID: PMC9700722 DOI: 10.1038/s41386-022-01453-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/10/2022]
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive technique for focal brain stimulation based on electromagnetic induction where a fluctuating magnetic field induces a small intracranial electric current in the brain. For more than 35 years, TMS has shown promise in the diagnosis and treatment of neurological and psychiatric disorders in adults. In this review, we provide a brief introduction to the TMS technique with a focus on repetitive TMS (rTMS) protocols, particularly theta-burst stimulation (TBS), and relevant rTMS-derived metrics of brain plasticity. We then discuss the TMS-EEG technique, the use of neuronavigation in TMS, the neural substrate of TBS measures of plasticity, the inter- and intraindividual variability of those measures, effects of age and genetic factors on TBS aftereffects, and then summarize alterations of TMS-TBS measures of plasticity in major neurological and psychiatric disorders including autism spectrum disorder, schizophrenia, depression, traumatic brain injury, Alzheimer's disease, and diabetes. Finally, we discuss the translational studies of TMS-TBS measures of plasticity and their therapeutic implications.
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Affiliation(s)
- Ali Jannati
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Lindsay M Oberman
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Alexander Rotenberg
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Alvaro Pascual-Leone
- Department of Neurology, Harvard Medical School, Boston, MA, USA.
- Hinda and Arthur Marcus Institute for Aging Research and Deanna and Sidney Wolk Center for Memory Health, Hebrew SeniorLife, Boston, MA, USA.
- Guttmann Brain Health Institute, Institut Guttmann, Barcelona, Spain.
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Michel-Flutot P, Jesus I, Mansart A, Bonay M, Lee KZ, Auré K, Vinit S. Evaluation of Gastrocnemius Motor Evoked Potentials Induced by Trans-Spinal Magnetic Stimulation Following Tibial Nerve Crush in Rats. BIOLOGY 2022; 11:biology11121834. [PMID: 36552344 PMCID: PMC9776027 DOI: 10.3390/biology11121834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/08/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Peripheral nerve injuries induce long-lasting physiological and severe functional impairment due to motor, sensory, and autonomic denervation. Preclinical models allow us to study the process of nerve damage, evaluate the capacity of the peripheral nervous system for spontaneous recovery, and test diagnostic tools to assess the damage and subsequent recovery. Methods: In this study on Sprague-Dawley rats, we: (1) compared the use of two different anesthetics (isoflurane and urethane) for the evaluation of motor evoked potentials (MEPs) induced by trans-spinal magnetic stimulation (TSMS) in gastrocnemius and brachioradialis muscles; (2) monitored the evolution of gastrocnemius MEPs by applying paired-pulse stimulation to evaluate the neuromuscular junction activity; and (3) evaluated the MEP amplitude before and after left tibialis nerve crush (up to 7 days post-injury under isoflurane anesthesia). The results showed that muscle MEPs had higher amplitudes under isoflurane anesthesia, as compared with urethane anesthesia in the rats, demonstrating higher motoneuronal excitability under isoflurane anesthesia evaluated by TSMS. Following tibial nerve crush, a significant reduction in gastrocnemius MEP amplitude was observed on the injured side, mainly due to axonal damage from the initial crush. No spontaneous recovery of MEP amplitude in gastrocnemius muscles was observed up to 7 days post-crush; even a nerve section did not induce any variation in residual MEP amplitude, suggesting that the initial crush effectively severed the axonal fibers. These observations were confirmed histologically by a drastic reduction in the remaining myelinated fibers in the crushed tibial nerve. These data demonstrate that TSMS can be reliably used to noninvasively evaluate peripheral nerve function in rats. This method could therefore readily be applied to evaluate nerve conductance in the clinical environment.
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Affiliation(s)
| | - Isley Jesus
- END-ICAP, UVSQ, Inserm, Université Paris-Saclay, 78000 Versailles, France
| | - Arnaud Mansart
- Infection et Inflammation (2I), UVSQ, Inserm, Université Paris-Saclay, 78000 Versailles, France
| | - Marcel Bonay
- END-ICAP, UVSQ, Inserm, Université Paris-Saclay, 78000 Versailles, France
| | - Kun-Ze Lee
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80424, Taiwan
| | - Karine Auré
- Department of Neurophysiology, Foch Hospital, 75073 Suresnes, France
| | - Stéphane Vinit
- END-ICAP, UVSQ, Inserm, Université Paris-Saclay, 78000 Versailles, France
- Correspondence: ; Tel.: +33-170-429-427
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Wang X, Wang T, Jin J, Wang H, Li Y, Liu Z, Yin T. Anesthesia inhibited corticospinal excitability and attenuated the modulation of repetitive transcranial magnetic stimulation. BMC Anesthesiol 2022; 22:111. [PMID: 35439927 PMCID: PMC9016971 DOI: 10.1186/s12871-022-01655-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 04/11/2022] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Lots of studies have measured motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) in anesthetized animals. However, in awake animals, the measurement of TMS-induced MEP is scarce as lack of sufficient restraint. So far, the explicit study of anesthesia effects on corticospinal excitability and repetitive TMS (rTMS) induced modulation is still lacking. This study aimed to: (1) measure TMS-induced MEP in both awake restrained and anesthetized rats, (2) investigate the effect of anesthesia on corticospinal excitability, and (3) on rTMS-induced modulation. METHODS MEP of eighteen rats were measured under both wakefulness and anesthesia using flexible binding and surface electrodes. Peak-to-peak MEP amplitudes, resting motor threshold (RMT) and the slope of stimulus response (SR) were extracted to investigate anesthesia effects on corticospinal excitability. Thereafter, 5 or 10 Hz rTMS was applied with 600 pulses, and the increase in MEP amplitude and the decrease in RMT were used to quantify rTMS-induced modulation. RESULTS The RMT in the awake condition was 44.6 ± 1.2% maximum output (MO), the peak-to-peak MEP amplitude was 404.6 ± 48.8 μV at 60% MO. Under anesthesia, higher RMT (55.6 ± 2.9% MO), lower peak-to-peak MEP amplitudes (258.6 ± 32.7 μV) and lower slope of SR indicated that the corticospinal excitability was suppressed. Moreover, under anesthesia, high-frequency rTMS still showed significant modulation of corticospinal excitability, but the modulation of MEP peak-to-peak amplitudes was weaker than that under wakefulness. CONCLUSIONS This study measured TMS-induced MEP in both awake and anesthetized rats, and provided explicit evidence for the inhibitory effects of anesthesia on corticospinal excitability and on high-frequency rTMS-induced modulation of MEP.
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Affiliation(s)
- Xin Wang
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Tengfei Wang
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Jingna Jin
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - He Wang
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Ying Li
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Zhipeng Liu
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.
| | - Tao Yin
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China. .,Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China.
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Fujiki M, Kuga K, Ozaki H, Kawasaki Y, Fudaba H. Blockade of Motor Cortical Long-Term Potentiation Induction by Glutamatergic Dysfunction Causes Abnormal Neurobehavior in an Experimental Subarachnoid Hemorrhage Model. Front Neural Circuits 2021; 15:670189. [PMID: 33897380 PMCID: PMC8063030 DOI: 10.3389/fncir.2021.670189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 03/17/2021] [Indexed: 01/11/2023] Open
Abstract
Subarachnoid hemorrhage (SAH) is a life-threatening condition that can also lead to permanent paralysis. However, the mechanisms that underlying neurobehavioral deficits after SAH have not been fully elucidated. As theta burst stimulation (TBS) can induce long-term potentiation (LTP) in the motor cortex, we tested its potential as a functional evaluation tool after experimentally induced SAH. Motor cortical inter-neuronal excitability was evaluated in anesthetized rats after 200 Hz-quadripulse TBS (QTS5), 200 Hz-quadripulse stimulation (QPS5), and 400 Hz-octapulse stimulation (OPS2.5). Furthermore, correlation between motor cortical LTP and N-methyl-D-aspartate-receptor activation was evaluated using MK-801, a NMDA-receptor antagonist. We evaluated inhibition-facilitation configurations [interstimulus interval: 3 ms; short-latency intracortical inhibition (SICI) and 11 ms; intracortical facilitation (ICF)] with paired electrical stimulation protocols and the effect of TBS paradigm on continuous recording of motor-evoked potentials (MEPs) for quantitative parameters. SAH and MK-801 completely blocked ICF, while SICI was preserved. QTS5, QPS5, and OPS2.5 facilitated continuous MEPs, persisting for 180 min. Both SAH and MK-801 completely blocked MEP facilitations after QPS5 and OPS2.5, while MEP facilitations after QTS5 were preserved. Significant correlations were found among neurological scores and 3 ms-SICI rates, 11 ms-ICF rates, and MEP facilitation rates after 200 Hz-QTS5, 7 days after SAH (R2 = 0.6236; r = −0.79, R2 = 0.6053; r = −0.77 and R2 = 0.9071; r = 0.95, p < 0.05, respectively). Although these findings need to be verified in humans, our study demonstrates that the neurophysiological parameters 3 ms-SICI, 11 ms-ICF, and 200 Hz-QTS5-MEPs may be useful surrogate quantitative biomarkers for assessing inter-neuronal function after SAH.
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Affiliation(s)
- Minoru Fujiki
- Department of Neurosurgery, School of Medicine, Oita University, Oita, Japan
| | - Kazuhiro Kuga
- Drug Safety Research and Evaluation, Takeda Pharmaceutical Company Limited, Fujisawa, Japan
| | - Harushige Ozaki
- Drug Safety Research and Evaluation, Takeda Pharmaceutical Company Limited, Fujisawa, Japan
| | - Yukari Kawasaki
- Department of Neurosurgery, School of Medicine, Oita University, Oita, Japan
| | - Hirotaka Fudaba
- Department of Neurosurgery, School of Medicine, Oita University, Oita, Japan
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Fujiki M, Kawasaki Y, Fudaba H. Continuous Theta-Burst Stimulation Intensity Dependently Facilitates Motor-Evoked Potentials Following Focal Electrical Stimulation of the Rat Motor Cortex. Front Neural Circuits 2020; 14:585624. [PMID: 33117132 PMCID: PMC7553073 DOI: 10.3389/fncir.2020.585624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/31/2020] [Indexed: 01/28/2023] Open
Abstract
Although theta-burst stimulation (TBS) is known to differentially modify motor cortical excitability according to stimulus conditions in humans, whether similar effects can be seen in animals, in particular rats, remains to be defined. Given the importance of experimental rat models for humans, this study explored this stimulation paradigm in rats. Specifically, this study aimed to explore corticospinal excitability after TBS in anesthetized animals to confirm its comparability with human results. Both inhibition-facilitation configurations using paired electrical stimulation protocols and the effects of the TBS paradigm on motor-evoked potentials (MEPs) in rat descending motor pathways were assessed. Paired-stimulation MEPs showed inhibition [interstimulus interval (ISI): 3 ms] and facilitation (11 ms) patterns under medetomidine/midazolam/butorphanol (MMB) anesthesia. Furthermore, while ketamine and xylazine (K/X) anesthesia completely blocked facilitation at 11-ms ISI, inhibition at a 3-ms ISI was preserved. Continuous and intermittent TBS strongly facilitated MEPs depending on stimulus intensity, persisting for up to 25 min under both MMB and K/X anesthesia. These findings are similar to the intracortical inhibition and facilitation observed in the human motor cortex using paired-pulse magnetic stimulation, particularly the glutamate-mediated facilitation phase. However, different TBS facilitatory mechanisms occur in the rat motor cortex. These different TBS facilitatory mechanisms affect the comparability and interpretations of TBS between rat and human models.
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Affiliation(s)
- Minoru Fujiki
- Department of Neurosurgery, School of Medicine, Oita University, Oita, Japan
| | - Yukari Kawasaki
- Department of Neurosurgery, School of Medicine, Oita University, Oita, Japan
| | - Hirotaka Fudaba
- Department of Neurosurgery, School of Medicine, Oita University, Oita, Japan
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Tsuboyama M, Kaye HL, Rotenberg A. Review of Transcranial Magnetic Stimulation in Epilepsy. Clin Ther 2020; 42:1155-1168. [PMID: 32624320 DOI: 10.1016/j.clinthera.2020.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 05/18/2020] [Accepted: 05/27/2020] [Indexed: 12/25/2022]
Abstract
PURPOSE Despite the availability of numerous pharmacologic and nonpharmacologic antiseizure therapies, a fraction of patients with epilepsy remain refractory to current treatment options, underscoring the need for novel drugs and neuromodulatory therapies. Transcranial magnetic stimulation (TMS), coupled with either electromyography or electroencephalography, enables rapid measurement of the cortical excitation/inhibition ratio, which is pathologically shifted toward excess excitability in patients with epilepsy. In this review, we summarize: (1) TMS protocols that have been deployed to identify promising compounds in the antiepilepsy drug (AED)-development pipeline, and (2) the therapeutic potential of TMS in the treatment of drug-resistant seizures. METHODS A focused literature review of the use of TMS in epilepsy, using a PubMed search, was performed. Over 70 articles were included that pertained to: (1) the use of TMS-EMG and TMS-EEG in elucidating the mechanisms of action of AEDs and in discovering potential new AEDs; and (2) the use of repetitive TMS in the treatment of seizures. FINDINGS Studies from the literature have reported that AEDs alter TMS-derived metrics, typically by leading to a net increase in cortical inhibition with successful therapy. Preclinical TMS work in rodent models of epilepsy has led to the development of novel antiseizure drug compounds. Clinical translational studies of TMS have been used to determine guidelines on the dosages of other agents in the AED pipeline in preparation for clinical trials. Several studies have described the use of therapeutic repetitive TMS in both the ictal and interictal states of epilepsy, with inconsistent results. IMPLICATIONS TMS has diagnostic and therapeutic potential in epilepsy. TMS-derived markers can enable early-stage measures of AED target engagement, and can facilitate studies of the pharmacokinetic and pharmacodynamic properties of AEDs. TMS may also be used in the early prediction of the efficacy of different AEDs in treating patients, and in direct neuromodulation of epileptic networks. From the therapeutics perspective, despite favorable results in some trials, the optimization of treatment paradigms and the determination of ideal candidates for TMS are still needed. Finally, preclinical experiments of TMS have provided mechanistic insight into its effects on the excitation/inhibition ratio, and may facilitate rational drug-device coupling paradigms. Overall, the capacity of TMS in both the modulation and measurement of changes in cortical excitability highlights its unique role in advancing antiepilepsy therapeutics.
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Affiliation(s)
- Melissa Tsuboyama
- Neuromodulation Program, Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Harper L Kaye
- Behavioral Neuroscience Program, Boston University School of Medicine, Boston, MA, USA
| | - Alexander Rotenberg
- Neuromodulation Program, Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Boston, MA, USA.
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12
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Gersner R, Paredes C, Hameed MQ, Dhamne SC, Pascual‐Leone A, Rotenberg A. Transcranial magnetic stimulation tracks subminute changes in cortical excitability during propofol anesthesia. Ann Clin Transl Neurol 2020; 7:384-389. [PMID: 32061019 PMCID: PMC7085996 DOI: 10.1002/acn3.50981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/16/2019] [Accepted: 12/28/2019] [Indexed: 11/25/2022] Open
Abstract
Automated anesthesia systems that continuously monitor cortical excitability (CE) changes to govern drug infusion rates, are desirable. Paired‐pulse transcranial magnetic stimulation (ppTMS), with electromyography (EMG), provides noninvasive CE measures. We tested whether, and with what temporal resolution, ppTMS‐EMG detects dose‐dependent CE in rats anesthetized with continuous intravenous propofol. Motor‐evoked potentials (MEPs) were recorded every 20 seconds as either propofol bolus or change in infusion rate was applied. ppTMS‐derived measures varied in direct proportion to propofol dose with subminute temporal resolution. We conclude that ppTMS‐EMG enables real‐time markers of target engagement by anesthetics that may be incorporated into an automated device.
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Affiliation(s)
- Roman Gersner
- The Neuromodulation ProgramDepartment of NeurologyBoston Children’s HospitalHarvard Medical SchoolBostonMassachusetts
| | - Carmen Paredes
- The Neuromodulation ProgramDepartment of NeurologyBoston Children’s HospitalHarvard Medical SchoolBostonMassachusetts
| | - Mustafa Q. Hameed
- The Neuromodulation ProgramDepartment of NeurologyBoston Children’s HospitalHarvard Medical SchoolBostonMassachusetts
- Department of NeurosurgeryBoston Children’s HospitalHarvard Medical SchoolBostonMassachusetts
| | - Sameer C. Dhamne
- The Neuromodulation ProgramDepartment of NeurologyBoston Children’s HospitalHarvard Medical SchoolBostonMassachusetts
| | - Alvaro Pascual‐Leone
- Department of NeurologyHebrew SeniorLifeHarvard Medical SchoolBostonMassachusetts
- Institut GuttmannUniversitat AutonomaBarcelonaSpain
| | - Alexander Rotenberg
- The Neuromodulation ProgramDepartment of NeurologyBoston Children’s HospitalHarvard Medical SchoolBostonMassachusetts
- Berenson‐Allen Center for Noninvasive Brain StimulationDepartment of NeurologyBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMassachusetts
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13
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Liu HH, He XK, Chen HY, Peng CW, Rotenberg A, Juan CH, Pei YC, Liu HL, Chiang YH, Wang JY, Feng XJ, Huang YZ, Hsieh TH. Neuromodulatory Effects of Transcranial Direct Current Stimulation on Motor Excitability in Rats. Neural Plast 2019; 2019:4252943. [PMID: 31949429 PMCID: PMC6942908 DOI: 10.1155/2019/4252943] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/14/2019] [Indexed: 11/17/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) is a noninvasive technique for modulating neural plasticity and is considered to have therapeutic potential in neurological disorders. For the purpose of translational neuroscience research, a suitable animal model can be ideal for providing a stable condition for identifying mechanisms that can help to explore therapeutic strategies. Here, we developed a tDCS protocol for modulating motor excitability in anesthetized rats. To examine the responses of tDCS-elicited plasticity, the motor evoked potential (MEP) and MEP input-output (IO) curve elicited by epidural motor cortical electrical stimulus were evaluated at baseline and after 30 min of anodal tDCS or cathodal tDCS. Furthermore, a paired-pulse cortical electrical stimulus was applied to assess changes in the inhibitory network by measuring long-interval intracortical inhibition (LICI) before and after tDCS. In the results, analogous to those observed in humans, the present study demonstrates long-term potentiation- (LTP-) and long-term depression- (LTD-) like plasticity can be induced by tDCS protocol in anesthetized rats. We found that the MEPs were significantly enhanced immediately after anodal tDCS at 0.1 mA and 0.8 mA and remained enhanced for 30 min. Similarly, MEPs were suppressed immediately after cathodal tDCS at 0.8 mA and lasted for 30 min. No effect was noted on the MEP magnitude under sham tDCS stimulation. Furthermore, the IO curve slope was elevated following anodal tDCS and presented a trend toward diminished slope after cathodal tDCS. No significant differences in the LICI ratio of pre- to post-tDCS were observed. These results indicated that developed tDCS schemes can produce consistent, rapid, and controllable electrophysiological changes in corticomotor excitability in rats. This newly developed tDCS animal model could be useful to further explore mechanical insights and may serve as a translational platform bridging human and animal studies, establishing new therapeutic strategies for neurological disorders.
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Affiliation(s)
- Hui-Hua Liu
- Department of Rehabilitation Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan, Taiwan
| | - Xiao-Kuo He
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan, Taiwan
- Department of Rehabilitation, The Fifth Hospital of Xiamen, Xiamen, Fujian, China
| | - Hsin-Yung Chen
- Department of Occupational Therapy and Institute of Behavioral Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Neurology and Dementia Center, Taoyuan Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
| | - Chih-Wei Peng
- School of Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, Taiwan
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Brain Research Center, National Central University, Taoyuan, Taiwan
| | - Yu-Cheng Pei
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Hao-Li Liu
- Department of Electrical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Yung-Hsiao Chiang
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan
- Graduate Program on Neuroregeneration, Taipei Medical University, Taipei, Taiwan
| | - Jia-Yi Wang
- Graduate Institute of Medical Sciences, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Xiao-Jun Feng
- Department of Rehabilitation Medicine, The Second Hospital of Anhui Medical University and Anhui Medical University, Hefei, China
| | - Ying-Zu Huang
- Department of Neurology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taipei, Taiwan
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
- Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Tsung-Hsun Hsieh
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan, Taiwan
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
- Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
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14
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Boonzaier J, Petrov PI, Otte WM, Smirnov N, Neggers SFW, Dijkhuizen RM. Design and Evaluation of a Rodent-Specific Transcranial Magnetic Stimulation Coil: An In Silico and In Vivo Validation Study. Neuromodulation 2019; 23:324-334. [PMID: 31353780 PMCID: PMC7216963 DOI: 10.1111/ner.13025] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/21/2019] [Accepted: 06/26/2019] [Indexed: 12/18/2022]
Abstract
Background Rodent models are fundamental in unraveling cellular and molecular mechanisms of transcranial magnetic stimulation (TMS)‐induced effects on the brain. However, proper translation of human TMS protocols to animal models have been restricted by the lack of rodent‐specific focal TMS coils. Objective We aimed to improve TMS focalization in rodent brain with a novel small, cooled, and rodent‐specific TMS coil. Methods A rodent‐specific 25‐mm figure‐of‐eight TMS coil was developed. Stimulation focalization was simulated in silico for the rodent coil and a commercial human 50‐mm figure‐of‐eight TMS coil. Both coils were also compared in vivo by electromyography measurements of brachialis motor evoked potential (MEP) responses to TMS at different brain sites in anesthetized rats (n = 6). Focalization was determined from the coils' level of stimulation laterality. Differences in MEPs were statistically analyzed with repeated‐measures, within‐subjects, ANOVA. Results In silico simulation results deemed the human coil insufficient for unilateral stimulation of the rat motor cortex, whereas lateralized electrical field induction was projected attainable with the rodent coil. Cortical, in vivo MEP amplitude measurements from multiple points in each hemisphere, revealed unilateral activation of the contralateral brachialis muscle, in absence of ipsilateral brachialis activation, with both coils. Conclusion Computer simulations motivated the design of a smaller rodent‐specific TMS coil, but came short in explaining the capability of a larger commercial human coil to induce unilateral MEPs in vivo. Lateralized TMS, as demonstrated for both TMS coils, corroborates their use in translational rodent studies, to elucidate mechanisms of action of therapeutic TMS protocols.
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Affiliation(s)
- Julia Boonzaier
- Biomedical Magnetic Resonance Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Petar I Petrov
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Willem M Otte
- Biomedical Magnetic Resonance Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands.,Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | | | - Sebastiaan F W Neggers
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Rick M Dijkhuizen
- Biomedical Magnetic Resonance Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
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15
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Effects of Athermal Shortwave Diathermy Treatment on Somatosensory Evoked Potentials and Motor Evoked Potentials in Rats With Spinal Cord Injury. Spine (Phila Pa 1976) 2019; 44:E749-E758. [PMID: 31205164 DOI: 10.1097/brs.0000000000002980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A study on shortwave diathermy (SWD) versus no treatment following induced spinal cord injury (SCI) in rats. OBJECTIVE To investigate the effects of athermal SWD treatment on somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) and hindlimb movements in rats with SCI. SUMMARY OF BACKGROUND DATA SWD has been proven to improve vascular circulation and reduce inflammation. However, there have been few studies on neuroprotective effect of SWD on SCI. METHODS Twenty-four female Sprague-Dawley (SD) rats were randomly divided into four groups: sham, SCI, SWD, and intact groups. The SCI model was established using the modified Allen weight-drop method. The SWD group received 15 sessions of athermal SWD treatment over a 3-week period of time at 24 hours after SCI. While the sham group and SCI group received no treatment after surgery. Hindlimb movements were evaluated by the Basso, Beattie, and Bresnahan (BBB) scale before surgery, and on days 1, 7, 14, and 21 after the surgery, respectively. The SEP and MEP measurements were simultaneously performed to detect the responses of neural conduction. RESULTS The week-by-week BBB scores showed a gradual improvement in the rats of both SCI and SWD groups from the first week to the end of the study; however, the BBB scores of the SWD group were higher than those of the SCI group over the course of 3 weeks. Data from the SEP and MEP measurements showed a significant improvement in the SWD group compared with the SCI group at each time point of observation, with a more prominent increase of amplitude and a more evident reduction of latency. There was a linear correlation between the BBB scores and the latency and amplitude of SEPs or MEPs. CONCLUSION Athermal SWD treatment might facilitate the recovery of locomotor function and exert neuroprotective effect on the SCI. LEVEL OF EVIDENCE N/A.
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16
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Li YT, Chen SC, Yang LY, Hsieh TH, Peng CW. Designing and Implementing a Novel Transcranial Electrostimulation System for Neuroplastic Applications: A Preliminary Study. IEEE Trans Neural Syst Rehabil Eng 2019; 27:805-813. [PMID: 30951469 DOI: 10.1109/tnsre.2019.2908674] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Recently, a specific repetitive transcranial magnetic stimulation (rTMS) waveform, namely, the theta burst stimulation (TBS) protocol, has been proposed for more efficiently inducing neuroplasticity for various clinic rehabilitation purposes. However, few studies have explored the feasibility of using the TBS combined with direct current (dc) waveform for brain neuromodulation; this waveform is transcranially delivered using electrical current power rather than magnetic power. This study implemented a prototype of a novel transcranial electrostimulation device that can flexibly output a waveform that combined dc and the TBS-like protocol and assessed the effects of the novel combinational waveform on neuroplasticity. An in vivo experiment was conducted first to validate the accuracy of the stimulator's current output at various impedance loads. Using this transcranial stimulator, a series of transcranial stimulation experiments was conducted on the brain cortex of rats, in which electrode-tissue impedance and motor evoked potentials (MEPs) were measured. These experiments were designed to assess the feasibility and efficacy of the new combinational waveforms for brain neuroplasticity. Our results indicated that the transcranial electrostimulation system exhibited satisfactory performance, as evidenced by the error percentage of less than 5% for current output. In the animal experiment, the dc combined with intermittent TBS-like protocol exerted a stronger neuroplastic effect than the conventional dc protocol. These results demonstrated that the combination of electrical dc and TBS-like protocols in our system can produce a new feasible therapeutic waveform for transcranially inducing a promising neuromodulatory effect on various diseases of the central nervous system.
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17
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Hsieh TH, Lee HHC, Hameed MQ, Pascual-Leone A, Hensch TK, Rotenberg A. Trajectory of Parvalbumin Cell Impairment and Loss of Cortical Inhibition in Traumatic Brain Injury. Cereb Cortex 2018; 27:5509-5524. [PMID: 27909008 DOI: 10.1093/cercor/bhw318] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 09/21/2016] [Indexed: 11/13/2022] Open
Abstract
Many neuropsychiatric symptoms that follow traumatic brain injury (TBI), including mood disorders, sleep disturbance, chronic pain, and posttraumatic epilepsy (PTE) are attributable to compromised cortical inhibition. However, the temporal trajectory of cortical inhibition loss and its underlying mechanisms are not known. Using paired-pulse transcranial magnetic stimulation (ppTMS) and immunohistochemistry, we tracked functional and cellular changes of cortical inhibitory network elements after fluid-percussion injury (FPI) in rats. ppTMS revealed a progressive loss of cortical inhibition as early as 2 weeks after FPI. This profile paralleled the increasing levels of cortical oxidative stress, which was accompanied by a gradual loss of parvalbumin (PV) immunoreactivity in perilesional cortex. Preceding the PV loss, we identified a degradation of the perineuronal net (PNN)-a specialized extracellular structure enwrapping cortical PV-positive (PV+) inhibitory interneurons which binds the PV+ cell maintenance factor, Otx2. The trajectory of these impairments underlies the reduced inhibitory tone, which can contribute to posttraumatic neurological conditions, such as PTE. Taken together, our results highlight the use of ppTMS as a biomarker to track the course of cortical inhibitory dysfunction post-TBI. Moreover, the neuroprotective role of PNNs on PV+ cell function suggests antioxidant treatment or Otx2 enhancement as a promising prophylaxis for post-TBI symptoms.
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Affiliation(s)
- Tsung-Hsun Hsieh
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.,Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 33305, Taiwan
| | - Henry Hing Cheong Lee
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mustafa Qadir Hameed
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Takao K Hensch
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, MA 02138, USA
| | - Alexander Rotenberg
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
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18
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Damar U, Gersner R, Johnstone JT, Kapur K, Collins S, Schachter S, Rotenberg A. Alterations in the Timing of Huperzine A Cerebral Pharmacodynamics in the Acute Traumatic Brain Injury Setting. J Neurotrauma 2017; 35:393-397. [PMID: 29054135 DOI: 10.1089/neu.2017.5258] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traumatic brain injury (TBI) may affect the pharmacodynamics of centrally acting drugs. Paired-pulse transcranial magnetic stimulation (ppTMS) is a safe and noninvasive measure of cortical gamma-aminobutyric acid (GABA)-mediated cortical inhibition. Huperzine A (HupA) is a naturally occurring acetylcholinesterase inhibitor with newly discovered potent GABA-mediated antiepileptic capacity, which is reliably detected by ppTMS. To test whether TBI alters cerebral HupA pharmacodynamics, we exposed rats to fluid percussion injury (FPI) and tested whether ppTMS metrics of cortical inhibition differ in magnitude and temporal pattern in injured rats. Anesthetized adult rats were exposed to FPI or sham injury. Ninety minutes post-TBI, rats were injected with HupA or saline (0.6 mg/kg, intraperitoneally). TBI resulted in reduced cortical inhibition 90 min after the injury (N = 18) compared to sham (N = 13) controls (p = 0.03). HupA enhanced cortical inhibition after both sham injury (N = 6; p = 0.002) and TBI (N = 6; p = 0.02). The median time to maximum HupA inhibition in sham and TBI groups were 46.4 and 76.5 min, respectively (p = 0.03). This was consistent with a quadratic trend comparison that projects HupA-mediated cortical inhibition to last longer in injured rats (p = 0.007). We show that 1) cortical GABA-mediated inhibition, as measured by ppTMS, decreases acutely post-TBI, 2) HupA restores lost post-TBI GABA-mediated inhibition, and 3) HupA-mediated enhancement of cortical inhibition is delayed post-TBI. The plausible reasons of the latter include 1) low HupA volume of distribution rendering HupA confined in the intravascular compartment, therefore vulnerable to reduced post-TBI cerebral perfusion, and 2) GABAR dysfunction and increased AChE activity post-TBI.
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Affiliation(s)
- Ugur Damar
- 1 F.M. Kirby Neurobiology Center , Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Roman Gersner
- 1 F.M. Kirby Neurobiology Center , Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Kush Kapur
- 1 F.M. Kirby Neurobiology Center , Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Steven Schachter
- 3 Department of Neurology, Beth Israel Deaconess Medical Center , and Massachusetts General Hospital,Harvard Medical School, Boston, Massachusetts
| | - Alexander Rotenberg
- 1 F.M. Kirby Neurobiology Center , Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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Sykes M, Matheson NA, Brownjohn PW, Tang AD, Rodger J, Shemmell JBH, Reynolds JNJ. Differences in Motor Evoked Potentials Induced in Rats by Transcranial Magnetic Stimulation under Two Separate Anesthetics: Implications for Plasticity Studies. Front Neural Circuits 2016; 10:80. [PMID: 27766073 PMCID: PMC5052269 DOI: 10.3389/fncir.2016.00080] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/26/2016] [Indexed: 11/25/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is primarily used in humans to change the state of corticospinal excitability. To assess the efficacy of different rTMS stimulation protocols, motor evoked potentials (MEPs) are used as a readout due to their non-invasive nature. Stimulation of the motor cortex produces a response in a targeted muscle, and the amplitude of this twitch provides an indirect measure of the current state of the cortex. When applied to the motor cortex, rTMS can alter MEP amplitude, however, results are variable between participants and across studies. In addition, the mechanisms underlying any change and its locus are poorly understood. In order to better understand these effects, MEPs have been investigated in vivo in animal models, primarily in rats. One major difference in protocols between rats and humans is the use of general anesthesia in animal experiments. Anesthetics are known to affect plasticity-like mechanisms and so may contaminate the effects of an rTMS protocol. In the present study, we explored the effect of anesthetic on MEP amplitude, recorded before and after intermittent theta burst stimulation (iTBS), a patterned rTMS protocol with reported facilitatory effects. MEPs were assessed in the brachioradialis muscle of the upper forelimb under two anesthetics: a xylazine/zoletil combination and urethane. We found MEPs could be induced under both anesthetics, with no differences in the resting motor threshold or the average baseline amplitudes. However, MEPs were highly variable between animals under both anesthetics, with the xylazine/zoletil combination showing higher variability and most prominently a rise in amplitude across the baseline recording period. Interestingly, application of iTBS did not facilitate MEP amplitude under either anesthetic condition. Although it is important to underpin human application of TMS with mechanistic examination of effects in animals, caution must be taken when selecting an anesthetic and in interpreting results during prolonged TMS recording.
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Affiliation(s)
- Matthew Sykes
- Brain Health Research Centre and Brain Research New Zealand Centre of Research ExcellenceDunedin, New Zealand; Department of Anatomy, University of OtagoDunedin, New Zealand; Experimental and Regenerative Neuroscience, School of Animal Biology, University of Western AustraliaPerth, WA, Australia
| | - Natalie A Matheson
- Brain Health Research Centre and Brain Research New Zealand Centre of Research ExcellenceDunedin, New Zealand; Department of Anatomy, University of OtagoDunedin, New Zealand
| | - Philip W Brownjohn
- Brain Health Research Centre and Brain Research New Zealand Centre of Research ExcellenceDunedin, New Zealand; School of Physical Education, Sport and Exercise Sciences, University of OtagoDunedin, New Zealand
| | - Alexander D Tang
- Experimental and Regenerative Neuroscience, School of Animal Biology, University of Western Australia Perth, WA, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neuroscience, School of Animal Biology, University of Western Australia Perth, WA, Australia
| | - Jonathan B H Shemmell
- Brain Health Research Centre and Brain Research New Zealand Centre of Research ExcellenceDunedin, New Zealand; School of Physical Education, Sport and Exercise Sciences, University of OtagoDunedin, New Zealand
| | - John N J Reynolds
- Brain Health Research Centre and Brain Research New Zealand Centre of Research ExcellenceDunedin, New Zealand; Department of Anatomy, University of OtagoDunedin, New Zealand
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20
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Farzan F, Vernet M, Shafi MMD, Rotenberg A, Daskalakis ZJ, Pascual-Leone A. Characterizing and Modulating Brain Circuitry through Transcranial Magnetic Stimulation Combined with Electroencephalography. Front Neural Circuits 2016; 10:73. [PMID: 27713691 PMCID: PMC5031704 DOI: 10.3389/fncir.2016.00073] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/07/2016] [Indexed: 12/18/2022] Open
Abstract
The concurrent combination of transcranial magnetic stimulation (TMS) with electroencephalography (TMS-EEG) is a powerful technology for characterizing and modulating brain networks across developmental, behavioral, and disease states. Given the global initiatives in mapping the human brain, recognition of the utility of this technique is growing across neuroscience disciplines. Importantly, TMS-EEG offers translational biomarkers that can be applied in health and disease, across the lifespan, and in humans and animals, bridging the gap between animal models and human studies. However, to utilize the full potential of TMS-EEG methodology, standardization of TMS-EEG study protocols is needed. In this article, we review the principles of TMS-EEG methodology, factors impacting TMS-EEG outcome measures, and the techniques for preventing and correcting artifacts in TMS-EEG data. To promote the standardization of this technique, we provide comprehensive guides for designing TMS-EEG studies and conducting TMS-EEG experiments. We conclude by reviewing the application of TMS-EEG in basic, cognitive and clinical neurosciences, and evaluate the potential of this emerging technology in brain research.
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Affiliation(s)
- Faranak Farzan
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, University of Toronto Toronto, ON, Canada
| | - Marine Vernet
- Berenson-Allen Center for Non-invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Mouhsin M D Shafi
- Berenson-Allen Center for Non-invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
| | - Alexander Rotenberg
- Berenson-Allen Center for Non-invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBoston, MA, USA; Neuromodulation Program, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBoston, MA, USA
| | - Zafiris J Daskalakis
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, University of Toronto Toronto, ON, Canada
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Non-invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA
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Tang A, Thickbroom G, Rodger J. Repetitive Transcranial Magnetic Stimulation of the Brain: Mechanisms from Animal and Experimental Models. Neuroscientist 2016; 23:82-94. [PMID: 26643579 DOI: 10.1177/1073858415618897] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Since the development of transcranial magnetic stimulation (TMS) in the early 1980s, a range of repetitive TMS (rTMS) protocols are now available to modulate neuronal plasticity in clinical and non-clinical populations. However, despite the wide application of rTMS in humans, the mechanisms underlying rTMS-induced plasticity remain uncertain. Animal and in vitro models provide an adjunct method of investigating potential synaptic and non-synaptic mechanisms of rTMS-induced plasticity. This review summarizes in vitro experimental studies, in vivo studies with intact rodents, and preclinical models of selected neurological disorders-Parkinson's disease, depression, and stroke. We suggest that these basic research findings can contribute to the understanding of how rTMS-induced plasticity can be modulated, including novel mechanisms such as neuroprotection and neurogenesis that have significant therapeutic potential.
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Affiliation(s)
- Alexander Tang
- 1 Experimental and Regenerative Neurosciences, School of Animal Biology, University of Western Australia, Perth, Australia
| | | | - Jennifer Rodger
- 1 Experimental and Regenerative Neurosciences, School of Animal Biology, University of Western Australia, Perth, Australia
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Tang AD, Lowe AS, Garrett AR, Woodward R, Bennett W, Canty AJ, Garry MI, Hinder MR, Summers JJ, Gersner R, Rotenberg A, Thickbroom G, Walton J, Rodger J. Construction and Evaluation of Rodent-Specific rTMS Coils. Front Neural Circuits 2016; 10:47. [PMID: 27445702 PMCID: PMC4928644 DOI: 10.3389/fncir.2016.00047] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/17/2016] [Indexed: 01/13/2023] Open
Abstract
Rodent models of transcranial magnetic stimulation (TMS) play a crucial role in aiding the understanding of the cellular and molecular mechanisms underlying TMS induced plasticity. Rodent-specific TMS have previously been used to deliver focal stimulation at the cost of stimulus intensity (12 mT). Here we describe two novel TMS coils designed to deliver repetitive TMS (rTMS) at greater stimulation intensities whilst maintaining spatial resolution. Two circular coils (8 mm outer diameter) were constructed with either an air or pure iron-core. Peak magnetic field strength for the air and iron-cores were 90 and 120 mT, respectively, with the iron-core coil exhibiting less focality. Coil temperature and magnetic field stability for the two coils undergoing rTMS, were similar at 1 Hz but varied at 10 Hz. Finite element modeling of 10 Hz rTMS with the iron-core in a simplified rat brain model suggests a peak electric field of 85 and 12.7 V/m, within the skull and the brain, respectively. Delivering 10 Hz rTMS to the motor cortex of anaesthetized rats with the iron-core coil significantly increased motor evoked potential amplitudes immediately after stimulation (n = 4). Our results suggest these novel coils generate modest magnetic and electric fields, capable of altering cortical excitability and provide an alternative method to investigate the mechanisms underlying rTMS-induced plasticity in an experimental setting.
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Affiliation(s)
- Alexander D Tang
- Experimental and Regenerative Neurosciences, School of Animal Biology, University of Western Australia Perth, WA, Australia
| | - Andrea S Lowe
- Departments of Communication Sciences & Disorders and Chemical & Biomedical Engineering, University of South FloridaTampa, FL, USA; Global Center for Hearing and Speech Research, University of South FloridaTampa, FL, USA
| | - Andrew R Garrett
- Experimental and Regenerative Neurosciences, School of Animal Biology, University of Western Australia Perth, WA, Australia
| | - Robert Woodward
- School of Physics, University of Western Australia Perth, WA, Australia
| | - William Bennett
- Wicking Dementia Research and Education Centre, University of Tasmania Hobart, TAS, Australia
| | - Alison J Canty
- Wicking Dementia Research and Education Centre, University of Tasmania Hobart, TAS, Australia
| | - Michael I Garry
- Human Motor Control Lab, School of Medicine, University of Tasmania Hobart, TAS, Australia
| | - Mark R Hinder
- Human Motor Control Lab, School of Medicine, University of Tasmania Hobart, TAS, Australia
| | - Jeffery J Summers
- Human Motor Control Lab, School of Medicine, University of TasmaniaHobart, TAS, Australia.; Research Institute for Sport and Exercise SciencesLiverpool John Moores University, UK
| | - Roman Gersner
- Department of Neurology, Boston Children's Hospital, Harvard Medical School Boston, MA, USA
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School Boston, MA, USA
| | - Gary Thickbroom
- Burke-Cornell Medical Research Institute White Plains, NY, USA
| | - Joseph Walton
- Departments of Communication Sciences & Disorders and Chemical & Biomedical Engineering, University of South FloridaTampa, FL, USA; Global Center for Hearing and Speech Research, University of South FloridaTampa, FL, USA
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Animal Biology, University of Western Australia Perth, WA, Australia
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Kimiskidis V. Transcranial magnetic stimulation (TMS) coupled with electroencephalography (EEG): Biomarker of the future. Rev Neurol (Paris) 2016; 172:123-6. [PMID: 26857413 DOI: 10.1016/j.neurol.2015.11.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 11/10/2015] [Indexed: 10/22/2022]
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Gersner R, Ekstein D, Dhamne S, Schachter S, Rotenberg A. Huperzine A prophylaxis against pentylenetetrazole-induced seizures in rats is associated with increased cortical inhibition. Epilepsy Res 2015; 117:97-103. [DOI: 10.1016/j.eplepsyres.2015.08.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/12/2015] [Accepted: 08/25/2015] [Indexed: 10/23/2022]
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Dhamne SC, Ekstein D, Zhuo Z, Gersner R, Zurakowski D, Loddenkemper T, Pascual-Leone A, Jensen FE, Rotenberg A. Acute seizure suppression by transcranial direct current stimulation in rats. Ann Clin Transl Neurol 2015; 2:843-56. [PMID: 26339678 PMCID: PMC4554445 DOI: 10.1002/acn3.226] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/03/2015] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE Cathodal transcranial direct current stimulation (tDCS) is a focal neuromodulation technique that suppresses cortical excitability by low-amplitude constant electrical current, and may have an antiepileptic effect. Yet, tDCS has not been tested in status epilepticus (SE). Furthermore, a combined tDCS and pharmacotherapy antiseizure approach is unexplored. We therefore examined in the rat pentylenetetrazol (PTZ) SE model whether cathodal tDCS (1) suppresses seizures, (2) augments lorazepam (LZP) efficacy, and (3) enhances GABAergic cortical inhibition. METHODS Experiment 1 aimed to identify an effective cathodal tDCS intensity. Rats received intraperitoneal PTZ followed by tDCS (sham, cathodal 1 mA, or cathodal 0.1 mA; for 20 min), and then a second PTZ challenge. In Experiment 2, two additional animal groups received a subtherapeutic LZP dose after PTZ, and then verum or sham tDCS. Clinical and electroencephalography (EEG) epileptic activity were compared between all groups. In Experiment 3, we measured GABA-mediated paired-pulse inhibition of the motor evoked potential by paired-pulse transcranial magnetic stimulation (ppTMS) in rats that received PTZ or saline, and either verum or sham tDCS. RESULTS Cathodal 1 mA tDCS (1) reduced EEG spike bursts, and suppressed clinical seizures after the second PTZ challenge, (2) in combination with LZP was more effective in seizure suppression and improved the clinical seizure outcomes compared to either tDCS or LZP alone, and (3) prevented the loss of ppTMS motor cortex inhibition that accompanied PTZ injection. INTERPRETATION These results suggest that cathodal 1 mA tDCS alone and in combination with LZP can suppress seizures by augmenting GABAergic cortical inhibition.
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Affiliation(s)
- Sameer C Dhamne
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, and the F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School Boston, Massachusetts, USA
| | - Dana Ekstein
- Department of Neurology, The Agnes Ginges Center of Human Neurogenetics, Hadassah-Hebrew University Medical Center Jerusalem, Israel
| | - Zhihong Zhuo
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, and the F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School Boston, Massachusetts, USA ; Department of Pediatric Neurology, The First Affiliated Hospital of Zhengzhou University Zhengzhou, China
| | - Roman Gersner
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, and the F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School Boston, Massachusetts, USA
| | - David Zurakowski
- Department of Anesthesia, Boston Children's Hospital, Harvard Medical School Boston, Massachusetts, USA
| | - Tobias Loddenkemper
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, and the F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School Boston, Massachusetts, USA
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, Massachusetts, USA
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania Health System Philadelphia, Pennsylvania, USA
| | - Alexander Rotenberg
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, and the F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School Boston, Massachusetts, USA ; Department of Pediatric Neurology, The First Affiliated Hospital of Zhengzhou University Zhengzhou, China ; Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, Massachusetts, USA
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French JA, Schachter SC, Sirven J, Porter R. The Epilepsy Foundation's 4th Biennial Epilepsy Pipeline Update Conference. Epilepsy Behav 2015; 46:34-50. [PMID: 25922152 DOI: 10.1016/j.yebeh.2015.02.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/09/2015] [Indexed: 10/23/2022]
Abstract
On June 5 and 6, 2014, the Epilepsy Foundation held its 4th Biennial Epilepsy Pipeline Update Conference, an initiative of the Epilepsy Therapy Project, which showcased the most promising epilepsy innovations from health-care companies and academic laboratories dedicated to pioneering and advancing drugs, biologics, technologies, devices, and diagnostics for epilepsy. Speakers and attendees included emerging biotech and medical technology companies, major pharmaceutical and device companies, as well as investigators and innovators at the cutting-edge of epilepsy. The program included panel discussions on collaboration between small and large companies, how to get products in need of funding to the marketplace, who is currently funding epilepsy and CNS innovation, and how the NIH facilitates early-stage drug development. Finally, the conference featured the third annual "Shark Tank" competition. The presentations are summarized in this paper, which is followed by a compilation of the meeting poster abstracts.
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Affiliation(s)
- Jacqueline A French
- Department of Neurology, New York University Langone Medical Center, New York, NY, USA
| | - Steven C Schachter
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA; Consortia for Improving Medicine Through Innovation and Technology, Boston, MA, USA.
| | - Joseph Sirven
- Department of Neurology, Mayo Clinic Scottsdale, Scottsdale, AZ, USA
| | - Roger Porter
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA; Department of Pharmacology, USUHS, Bethesda, MD, USA
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Charalambous CC, Bowden MG, Adkins DL. Motor Cortex and Motor Cortical Interhemispheric Communication in Walking After Stroke: The Roles of Transcranial Magnetic Stimulation and Animal Models in Our Current and Future Understanding. Neurorehabil Neural Repair 2015; 30:94-102. [PMID: 25878201 DOI: 10.1177/1545968315581418] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Despite the plethora of human neurophysiological research, the bilateral involvement of the leg motor cortical areas and their interhemispheric interaction during both normal and impaired human walking is poorly understood. Using transcranial magnetic stimulation (TMS), we have expanded our understanding of the role upper-extremity motor cortical areas play in normal movements and how stroke alters this role, and probed the efficacy of interventions to improve post-stroke arm function. However, similar investigations of the legs have lagged behind, in part, due to the anatomical difficulty in using TMS to stimulate the leg motor cortical areas. Additionally, leg movements are predominately bilaterally controlled and require interlimb coordination that may involve both hemispheres. The sensitive, but invasive, tools used in animal models of locomotion hold great potential for increasing our understanding of the bihemispheric motor cortical control of walking. In this review, we discuss 3 themes associated with the bihemispheric motor cortical control of walking after stroke: (a) what is known about the role of the bihemispheric motor cortical control in healthy and poststroke leg movements, (b) how the neural remodeling of the contralesional hemisphere can affect walking recovery after a stroke, and (c) what is the effect of behavioral rehabilitation training of walking on the neural remodeling of the motor cortical areas bilaterally. For each theme, we discuss how rodent models can enhance the present knowledge on human walking by testing hypotheses that cannot be investigated in humans, and how these findings can then be back-translated into the neurorehabilitation of poststroke walking.
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Affiliation(s)
- Charalambos C Charalambous
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA
| | - Mark G Bowden
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - DeAnna L Adkins
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, USA Department of Neurosciences, Medical University of South Carolina, Charleston, SC
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Novel Use of Theta Burst Cortical Electrical Stimulation for Modulating Motor Plasticity in Rats. J Med Biol Eng 2015. [DOI: 10.1007/s40846-015-0006-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Muller PA, Dhamne SC, Vahabzadeh-Hagh AM, Pascual-Leone A, Jensen FE, Rotenberg A. Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation. PLoS One 2014; 9:e91065. [PMID: 24646791 PMCID: PMC3960125 DOI: 10.1371/journal.pone.0091065] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 02/07/2014] [Indexed: 12/24/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS) is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP), presumably reflecting long-term depression (LTD) -like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1) reproduce cortico-spinal depression by LF rTMS in rats, (2) establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3) test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR), by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered.
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Affiliation(s)
- Paul A. Muller
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sameer C. Dhamne
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Andrew M. Vahabzadeh-Hagh
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
- Institut Universitari de Neurorehabilitació Guttmann, Universidad Autónoma de Barcelona, Badalona, Spain
| | - Frances E. Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania Health System, Philadelphia, Pennsylvania, United States of America
| | - Alexander Rotenberg
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Hsieh TH, Huang YZ, Rotenberg A, Pascual-Leone A, Chiang YH, Wang JY, Chen JJJ. Functional Dopaminergic Neurons in Substantia Nigra are Required for Transcranial Magnetic Stimulation-Induced Motor Plasticity. Cereb Cortex 2014; 25:1806-14. [DOI: 10.1093/cercor/bht421] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Paired-Pulse Transcranial Magnetic Stimulation (TMS) Protocols. TRANSCRANIAL MAGNETIC STIMULATION 2014. [DOI: 10.1007/978-1-4939-0879-0_6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Iglesias-Bregna D, Hanak S, Ji Z, Petty M, Liu L, Zhang D, McMonagle-Strucko K. Effects of prophylactic and therapeutic teriflunomide in transcranial magnetic stimulation-induced motor-evoked potentials in the dark agouti rat model of experimental autoimmune encephalomyelitis. J Pharmacol Exp Ther 2013; 347:203-11. [PMID: 23892570 DOI: 10.1124/jpet.113.205146] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Teriflunomide is a once-daily oral immunomodulatory agent recently approved in the United States for the treatment of relapsing multiple sclerosis (RMS). This study investigated neurophysiological deficits in descending spinal cord motor tracts during experimental autoimmune encephalomyelitis (EAE; a model of multiple sclerosis) and the functional effectiveness of prophylactic or therapeutic teriflunomide treatment in preventing the debilitating paralysis observed in this model. Relapsing-remitting EAE was induced in Dark Agouti rats using rat spinal cord homogenate. Animals were treated with oral teriflunomide (10 mg/kg daily) prophylactically, therapeutically, or with vehicle (control). Transcranial magnetic motor-evoked potentials were measured throughout the disease to provide quantitative assessment of the neurophysiological status of descending motor tracts. Axonal damage was quantified histologically by silver staining. Both prophylactic and therapeutic teriflunomide treatment significantly reduced maximum EAE disease scores (P < 0.0001 and P = 0.0001, respectively) compared with vehicle-treated rats. Electrophysiological recordings demonstrated that both teriflunomide treatment regimens prevented a delay in wave-form latency and a decrease in wave-form amplitude compared with that observed in vehicle-treated animals. A significant reduction in axonal loss was observed with both teriflunomide treatment regimens compared with vehicle (P < 0.0001 and P = 0.0014, respectively). The results of this study suggest that therapeutic teriflunomide can prevent the deficits observed in this animal model in descending spinal cord motor tracts. The mechanism behind reduced axonal loss and improved motor function may be primarily the reduced inflammation and consequent demyelination observed in these animals through the known effects of teriflunomide on impairing proliferation of stimulated T cells. These findings may have significant implications for patients with RMS.
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Vahabzadeh-Hagh AM, Muller PA, Gersner R, Zangen A, Rotenberg A. Translational neuromodulation: approximating human transcranial magnetic stimulation protocols in rats. Neuromodulation 2012; 15:296-305. [PMID: 22780329 PMCID: PMC5764706 DOI: 10.1111/j.1525-1403.2012.00482.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Transcranial magnetic stimulation (TMS) is a well-established clinical protocol with numerous potential therapeutic and diagnostic applications. Yet, much work remains in the elucidation of TMS mechanisms, optimization of protocols, and in development of novel therapeutic applications. As with many technologies, the key to these issues lies in the proper experimentation and translation of TMS methods to animal models, among which rat models have proven popular. A significant increase in the number of rat TMS publications has necessitated analysis of their relevance to human work. We therefore review the essential principles for the approximation of human TMS protocols in rats as well as specific methods that addressed these issues in published studies. MATERIALS AND METHODS We performed an English language literature search combined with our own experience and data. We address issues that we see as important in the translation of human TMS methods to rat models and provide a summary of key accomplishments in these areas. RESULTS An extensive literature review illustrated the growth of rodent TMS studies in recent years. Current advances in the translation of single, paired-pulse, and repetitive stimulation paradigms to rodent models are presented. The importance of TMS in the generation of data for preclinical trials is also highlighted. CONCLUSIONS Rat TMS has several limitations when considering parallels between animal and human stimulation. However, it has proven to be a useful tool in the field of translational brain stimulation and will likely continue to aid in the design and implementation of stimulation protocols for therapeutic and diagnostic applications.
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Affiliation(s)
- Andrew M. Vahabzadeh-Hagh
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Paul A. Muller
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Roman Gersner
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Abraham Zangen
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Rotenberg
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Abstract
Studies in rodents show that transient receptor potential vanilloid 1 (TRPV1) channels regulate glutamate release at central and peripheral synapses. In humans, a number of nonsynonymous single-nucleotide polymorphisms (SNPs) have been described in the TRPV1 gene, and some of them significantly alter the functionality of the channel. To address the possible role of TRPV1 channels in the regulation of synaptic transmission in humans, we studied how TRPV1 genetic polymorphisms affect cortical excitability measured with transcranial magnetic stimulation (TMS). Two SNPs of the TRPV1 gene were selected and genotyped (rs222747 and rs222749) in a sample of 77 healthy subjects. In previous cell expression studies, the "G" allele of rs222747 was found to enhance the activity of the channel, whereas rs222749 had no functional effect. Allelic variants in the rs222749 region were not associated with altered cortical response to single, paired, and repetitive TMS. In contrast, subjects homozygous for the G allele in rs222747 exhibited larger short-interval intracortical facilitation (a measure of glutamate transmission) explored through paired-pulse TMS of the primary motor cortex. Recruitment curves, short-interval intracortical inhibition, intracortical facilitation, and long-interval intracortical inhibition were unchanged. LTP- and LTD-like plasticity explored through intermittent or continuous theta-burst stimulation was also similar in the "G" and "non-G" subjects. To our knowledge, our results provide the first evidence that TRPV1 channels regulate cortical excitability to paired-pulse stimulation in humans.
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Hsieh TH, Dhamne SC, Chen JJJ, Pascual-Leone A, Jensen FE, Rotenberg A. A new measure of cortical inhibition by mechanomyography and paired-pulse transcranial magnetic stimulation in unanesthetized rats. J Neurophysiol 2011; 107:966-72. [PMID: 22013238 DOI: 10.1152/jn.00690.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Paired-pulse transcranial magnetic stimulation (ppTMS) is a safe and noninvasive tool for measuring cortical inhibition in humans, particularly in patients with disorders of cortical inhibition such as epilepsy. However, ppTMS protocols in rodent disease models, where mechanistic insight into the ppTMS physiology and into disease processes may be obtained, have been limited due to the requirement for anesthesia and needle electromyography. To eliminate the confounding factor of anesthesia and to approximate human ppTMS protocols in awake rats, we adapted the mechanomyogram (MMG) method to investigate the ppTMS inhibitory phenomenon in awake rats and then applied differential pharmacology to test the hypothesis that long-interval cortical inhibition is mediated by the GABA(A) receptor. Bilateral hindlimb-evoked MMGs were elicited in awake rats by long-interval ppTMS protocols with 50-, 100-, and 200-ms interstimulus intervals. Acute changes in ppTMS-MMG were measured before and after intraperitoneal injections of saline, the GABA(A) agonist pentobarbital (PB), and GABA(A) antagonist pentylenetetrazole (PTZ). An evoked MMG was obtained in 100% of animals by single-pulse stimulation, and ppTMS resulted in predictable inhibition of the test-evoked MMG. With increasing TMS intensity, MMG amplitudes increased in proportion to machine output to produce reliable input-output curves. Simultaneous recordings of electromyography and MMG showed a predictable latency discrepancy between the motor-evoked potential and the evoked MMG (7.55 ± 0.08 and 9.16 ± 0.14 ms, respectively). With pharmacological testing, time course observations showed that ppTMS-MMG inhibition was acutely reduced following PTZ (P < 0.05), acutely enhanced after PB (P < 0.01) injection, and then recovered to pretreatment baseline after 1 h. Our data support the application of the ppTMS-MMG technique for measuring the cortical excitability in awake rats and provide the evidence that GABA(A) receptor contributes to long-interval paired-pulse cortical inhibition. Thus ppTMS-MMG appears a well-tolerated biomarker for measuring GABA(A)-mediated cortical inhibition in rats.
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Affiliation(s)
- Tsung-Hsun Hsieh
- Department of Neurology, Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Pascual-Leone A, Freitas C, Oberman L, Horvath JC, Halko M, Eldaief M, Bashir S, Vernet M, Shafi M, Westover B, Vahabzadeh-Hagh AM, Rotenberg A. Characterizing brain cortical plasticity and network dynamics across the age-span in health and disease with TMS-EEG and TMS-fMRI. Brain Topogr 2011; 24:302-15. [PMID: 21842407 PMCID: PMC3374641 DOI: 10.1007/s10548-011-0196-8] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 01/21/2023]
Abstract
Brain plasticity can be conceptualized as nature's invention to overcome limitations of the genome and adapt to a rapidly changing environment. As such, plasticity is an intrinsic property of the brain across the lifespan. However, mechanisms of plasticity may vary with age. The combination of transcranial magnetic stimulation (TMS) with electroencephalography (EEG) or functional magnetic resonance imaging (fMRI) enables clinicians and researchers to directly study local and network cortical plasticity, in humans in vivo, and characterize their changes across the age-span. Parallel, translational studies in animals can provide mechanistic insights. Here, we argue that, for each individual, the efficiency of neuronal plasticity declines throughout the age-span and may do so more or less prominently depending on variable 'starting-points' and different 'slopes of change' defined by genetic, biological, and environmental factors. Furthermore, aberrant, excessive, insufficient, or mistimed plasticity may represent the proximal pathogenic cause of neurodevelopmental and neurodegenerative disorders such as autism spectrum disorders or Alzheimer's disease.
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Affiliation(s)
- Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
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Funke K, Benali A. Modulation of cortical inhibition by rTMS - findings obtained from animal models. J Physiol 2011; 589:4423-35. [PMID: 21768267 DOI: 10.1113/jphysiol.2011.206573] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) has become a popular method to non-invasively stimulate the human brain. The opportunity to modify cortical excitability with repetitive stimulation (rTMS) has especially gained interest for its therapeutic potential. However, details of the cellular mechanisms of the effects of rTMS are scarce. Currently favoured are long-term changes in the efficiency of excitatory synaptic transmission, with low-frequency rTMS depressing it, but high-frequency rTMS augmenting. Only recently has modulation of cortical inhibition been considered as an alternative way to explain lasting changes in cortical excitability induced by rTMS. Adequate animal models help to highlight stimulation-induced changes in cellular processes which are not assessable in human rTMS studies. In this review article, we summarize findings obtained with our rat models which indicate that distinct inhibitory cell classes, like the fast-spiking cells characterized by parvalbumin expression, are most sensitive to certain stimulation protocols, e.g. intermittent theta burst stimulation. We discuss how our findings can support the recently suggested models of gating and homeostatic plasticity as possible mechanisms of rTMS-induced changes in cortical excitability.
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Affiliation(s)
- Klaus Funke
- Institute of Physiology, Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum, 44780 Bochum, Germany.
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