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Farzan F. Transcranial Magnetic Stimulation-Electroencephalography for Biomarker Discovery in Psychiatry. Biol Psychiatry 2024; 95:564-580. [PMID: 38142721 DOI: 10.1016/j.biopsych.2023.12.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 12/08/2023] [Accepted: 12/15/2023] [Indexed: 12/26/2023]
Abstract
Current diagnosis and treatment of psychiatric illnesses are still based on behavioral observations and self-reports, commonly leading to prolonged untreated illness. Biological markers (biomarkers) may offer an opportunity to revolutionize clinical psychiatry practice by helping provide faster and potentially more effective therapies. Transcranial magnetic stimulation concurrent with electroencephalography (TMS-EEG) is a noninvasive brain mapping methodology that can assess the functions and dynamics of specific brain circuitries in awake humans and aid in biomarker discovery. This article provides an overview of TMS-EEG-based biomarkers that may hold potential in psychiatry. The methodological readiness of the TMS-EEG approach and steps in the validation of TMS-EEG biomarkers for clinical utility are discussed. Biomarker discovery with TMS-EEG is in the early stages, and several validation steps are still required before clinical implementations are realized. Thus far, TMS-EEG predictors of response to magnetic brain stimulation treatments in particular have shown promise for translation to clinical practice. Larger-scale studies can confirm validation followed by biomarker-informed trials to assess added value compared to existing practice.
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Affiliation(s)
- Faranak Farzan
- eBrain Lab, School of Mechatronic Systems Engineering, Simon Fraser University, Surrey, British Columbia, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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2
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Chen L, Klooster DCW, Tik M, Thomas EHX, Downar J, Fitzgerald PB, Williams NR, Baeken C. Accelerated Repetitive Transcranial Magnetic Stimulation to Treat Major Depression: The Past, Present, and Future. Harv Rev Psychiatry 2023; 31:142-161. [PMID: 37171474 PMCID: PMC10188211 DOI: 10.1097/hrp.0000000000000364] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is an effective and evidence-based therapy for treatment-resistant major depressive disorder. A conventional course of rTMS applies 20-30 daily sessions over 4-6 weeks. The schedule of rTMS delivery can be accelerated by applying multiple stimulation sessions per day, which reduces the duration of a treatment course with a predefined number of sessions. Accelerated rTMS reduces time demands, improves clinical efficiency, and potentially induces faster onset of antidepressant effects. However, considerable heterogeneity exists across study designs. Stimulation protocols vary in parameters such as the stimulation target, frequency, intensity, number of pulses applied per session or over a course of treatment, and duration of intersession intervals. In this article, clinician-researchers and neuroscientists who have extensive research experience in accelerated rTMS synthesize a consensus based on two decades of investigation and development, from early studies ("Past") to contemporaneous theta burst stimulation, a time-efficient form of rTMS gaining acceptance in clinical settings ("Present"). We propose descriptive nomenclature for accelerated rTMS, recommend avenues to optimize therapeutic and efficiency potential, and suggest using neuroimaging and electrophysiological biomarkers to individualize treatment protocols ("Future"). Overall, empirical studies show that accelerated rTMS protocols are well tolerated and not associated with serious adverse effects. Importantly, the antidepressant efficacy of accelerated rTMS appears comparable to conventional, once daily rTMS protocols. Whether accelerated rTMS induces antidepressant effects more quickly remains uncertain. On present evidence, treatment protocols incorporating high pulse dose and multiple treatments per day show promise and improved efficacy.
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Affiliation(s)
- Leo Chen
- From the Monash Alfred Psychiatry Research Centre, Department of Psychiatry, Central Clinical School, Monash University, Melbourne, Australia (Drs. Chen, Thomas); Ghent Experimental Psychiatry (GHEP) Lab, Department of Head and Skin (UZGent), Ghent University, Ghent, Belgium (Drs. Klooster, Baeken); Department of Psychiatry and Behavioral Sciences, Stanford University Medical Center, Stanford University, Stanford, CA (Drs. Tik, Williams); Institute of Medical Science and Department of Psychiatry, University of Toronto, Canada (Dr. Downar); School of Medicine and Psychology, he Australian National University, Canberra, Australia (Dr. Fitzgerald)
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3
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Cao N, Pi Y, Qiu F, Wang Y, Xia X, Liu Y, Zhang J. Plasticity changes in dorsolateral prefrontal cortex associated with procedural sequence learning are hemisphere-specific. Neuroimage 2022; 259:119406. [PMID: 35752417 DOI: 10.1016/j.neuroimage.2022.119406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 05/31/2022] [Accepted: 06/21/2022] [Indexed: 11/19/2022] Open
Abstract
Corticocortical neuroplastic changes from higher-order cortices to primary motor cortex (M1) have been described for procedural sequence learning. The dorsolateral prefrontal cortex (DLPFC) plays critical roles in cognition, including in motor learning and memory. However, neuroplastic changes in the DLPFC and their influence on M1 and on motor learning are not well understood. The present study examined bilateral DLPFC-M1 changes in plasticity induced by procedural motor sequence learning in a serial reaction time task. DLPFC plasticity induced by procedural sequence learning was examined by comparing before vs. after training assessments of ipsilateral/contralateral DLPFC-M1 interactions between sequence order and random order trials performed using either the left or right hand. Intra-hemispheric (inter-stimulus interval [ISI] = 10 ms) and inter-hemispheric (ISI = 10 or 50 ms) DLPFC-M1 interactions and single-pulse motor-evoked potentials (MEPs) were measured with transcranial magnetic stimulation (TMS). The reaction times of participants measured during motor training were faster for sequence learning than for random learning with either hand. Paired-pulse TMS induced DLPFC-M1 interactions that were disinhibited after motor sequence learning, especially for left DLPFC-left M1 interactions with right hand task performance and for left DLPFC-right M1 interactions with left hand task performance. These findings indicate that motor sequence learning induces neuroplastic changes to enhance DLPFC-M1 interactions. This manifestation of plasticity showed hemispheric specificity, favoring the left DLPFC. DLPFC plasticity may be a useful index of DLPFC function and may be a treatment target for enhancing DLPFC function and motor learning.
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Affiliation(s)
- Na Cao
- School of Psychology, Shanghai University of Sport, Shanghai, China; Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan; Japan Society for the Promotion of Science, Tokyo, Japan
| | - Yanling Pi
- Shanghai Punan Hospital of Pudong New District, Shanghai, China
| | - Fanghui Qiu
- School of Physical Education, Qingdao University, Qingdao, China
| | - Yanqiu Wang
- School of Psychology, Shanghai University of Sport, Shanghai, China
| | - Xue Xia
- School of Psychology, Shanghai University of Sport, Shanghai, China
| | - Yu Liu
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Jian Zhang
- School of Psychology, Shanghai University of Sport, Shanghai, China.
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Farzan F, Bortoletto M. Identification and verification of a 'true' TMS evoked potential in TMS-EEG. J Neurosci Methods 2022; 378:109651. [PMID: 35714721 DOI: 10.1016/j.jneumeth.2022.109651] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 04/05/2022] [Accepted: 06/09/2022] [Indexed: 11/19/2022]
Abstract
The concurrent combination of transcranial magnetic stimulation and electroencephalography (TMS-EEG) can unveil functional neural mechanisms with applications in basic and clinical research. In particular, TMS-evoked potentials (TEPs) potentially allow studying excitability and connectivity of the cortex in a causal manner that is not easily or non-invasively attainable with other neuroimaging techniques. The TEP waveform is obtained by isolating the EEG responses phase-locked to the time of TMS application. The intended component in a TEP waveform is the cortical activation by the TMS-induced electric current, free of instrumental and physiological artifact sources. This artifact-free cortical activation can be referred to as 'true' TEP. However, due to many unwanted auxiliary effects of TMS, the interpretation of 'true' TEPs has not been free of controversy. This paper reviews the most recent understandings of 'true' TEPs and their application. In the first part of the paper, TEP components are defined according to recommended methodologies. In the second part, the verification of 'true' TEP is discussed along with its sensitivity to brain-state, age, and disease. The various proposed origins of TEP components are then presented in the context of existing literature. Throughout the paper, lessons learned from the past TMS-EEG studies are highlighted to guide the identification and interpretation of 'true' TEPs in future studies.
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Affiliation(s)
- Faranak Farzan
- eBrain Lab, School of Mechatronic Systems Engineering, Simon Fraser University, Surrey, British Columbia, Canada; University of Toronto, Department of Psychiatry, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
| | - Marta Bortoletto
- Neurophysiology lab, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
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Hui J, Zomorrodi R, Lioumis P, Salavati B, Rajji TK, Chen R, Blumberger DM, Daskalakis ZJ. Pharmacological mechanisms of interhemispheric signal propagation: a TMS-EEG study. Neuropsychopharmacology 2020; 45:932-939. [PMID: 31357206 PMCID: PMC7162860 DOI: 10.1038/s41386-019-0468-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 02/03/2023]
Abstract
Interhemispheric connections across the corpus callosum have a predominantly inhibitory effect. Previous electrophysiology studies imply that local inhibitory circuits are responsible for inducing transcallosal inhibition, likely through inhibitory GABAB-mediated neurotransmission. We investigated the neurochemical mechanisms involved in interhemispheric connectivity by measuring transcranial magnetic stimulation (TMS)-induced interhemispheric signal propagation (ISP) in the motor cortex and dorsolateral prefrontal cortex (DLPFC) with electroencephalography (EEG) recordings under the pharmacological effects of baclofen, L-DOPA, dextromethorphan, and rivastigmine. We hypothesized that for both stimulated regions, GABAB receptor agonist baclofen would decrease ISP when compared against baseline while drugs that target other neurotransmitter systems (dopaminergic, acetylcholinergic, and glutamatergic systems) would have no effect on ISP. Twelve right-handed healthy volunteers completed this study and underwent TMS across five sessions in a randomized order. In the motor cortex, participants showed a significant decrease in ISP under baclofen, but not in the other drug conditions. There were no drug-induced changes in ISP in the DLPFC and baseline ISP did not differ across experimental sessions for both brain regions. Together, our results suggest that the inhibitory effects observed with interhemispheric signal transmission are mediated by a population of interneurons involving GABAB receptor neurotransmission. Inhibitory mechanisms of ISP may be more salient for motor-related functions in the motor cortex than for cognitive control in the DLPFC. These findings are a fundamental step in advancing our understanding of interhemispheric connectivity and may be used to identify treatments for disorders in which transcallosal transmission is dysfunctional.
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Affiliation(s)
- Jeanette Hui
- 0000 0000 8793 5925grid.155956.bTemerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON Canada ,0000 0001 2157 2938grid.17063.33Institute of Medical Science, University of Toronto, Toronto, ON Canada
| | - Reza Zomorrodi
- 0000 0000 8793 5925grid.155956.bTemerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON Canada
| | - Pantelis Lioumis
- 0000 0000 8793 5925grid.155956.bTemerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON Canada ,0000000108389418grid.5373.2Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Bahar Salavati
- 0000 0001 2157 2938grid.17063.33Institute of Medical Science, University of Toronto, Toronto, ON Canada
| | - Tarek K. Rajji
- 0000 0000 8793 5925grid.155956.bTemerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON Canada ,0000 0001 2157 2938grid.17063.33Institute of Medical Science, University of Toronto, Toronto, ON Canada ,0000 0001 2157 2938grid.17063.33Department of Psychiatry, University of Toronto, Toronto, ON Canada
| | - Robert Chen
- 0000 0001 2157 2938grid.17063.33Institute of Medical Science, University of Toronto, Toronto, ON Canada ,0000 0004 0474 0428grid.231844.8Krembil Brain Institute, University Health Network and Division of Neurology, Toronto, ON Canada
| | - Daniel M. Blumberger
- 0000 0000 8793 5925grid.155956.bTemerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON Canada ,0000 0001 2157 2938grid.17063.33Institute of Medical Science, University of Toronto, Toronto, ON Canada ,0000 0001 2157 2938grid.17063.33Department of Psychiatry, University of Toronto, Toronto, ON Canada
| | - Zafiris J. Daskalakis
- 0000 0000 8793 5925grid.155956.bTemerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON Canada ,0000 0001 2157 2938grid.17063.33Institute of Medical Science, University of Toronto, Toronto, ON Canada ,0000 0001 2157 2938grid.17063.33Department of Psychiatry, University of Toronto, Toronto, ON Canada
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6
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Noda Y. Toward the establishment of neurophysiological indicators for neuropsychiatric disorders using transcranial magnetic stimulation-evoked potentials: A systematic review. Psychiatry Clin Neurosci 2020; 74:12-34. [PMID: 31587446 DOI: 10.1111/pcn.12936] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 08/14/2019] [Accepted: 09/23/2019] [Indexed: 12/24/2022]
Abstract
Transcranial magnetic stimulation (TMS) can depolarize the neurons directly under the coil when applied to the cerebral cortex, and modulate the neural circuit associated with the stimulation site, which makes it possible to measure the neurophysiological index to evaluate excitability and inhibitory functions. Concurrent TMS and electroencephalography (TMS-EEG) has been developed to assess the neurophysiological characteristics of cortical regions other than the motor cortical region noninvasively. The aim of this review is to comprehensively discuss TMS-EEG research in the healthy brain focused on excitability, inhibition, and plasticity following neuromodulatory TMS paradigms from a neurophysiological perspective. A search was conducted in PubMed to identify articles that examined humans and that were written in English and published by September 2018. The search terms were as follows: (TMS OR 'transcranial magnetic stimulation') AND (EEG OR electroencephalog*) NOT (rTMS OR 'repetitive transcranial magnetic stimulation' OR TBS OR 'theta burst stimulation') AND (healthy). The study presents an overview of TMS-EEG methodology and neurophysiological indices and reviews previous findings from TMS-EEG in healthy individuals. Furthermore, this review discusses the potential application of TMS-EEG neurophysiology in the clinical setting to study healthy and diseased brain conditions in the future. Combined TMS-EEG is a powerful tool to probe and map neural circuits in the human brain noninvasively and represents a promising approach for determining the underlying pathophysiology of neuropsychiatric disorders.
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Affiliation(s)
- Yoshihiro Noda
- Multidisciplinary Translational Research Lab, Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
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7
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Hui J, Lioumis P, Blumberger DM, Daskalakis ZJ. Non-invasive Central Neuromodulation with Transcranial Magnetic Stimulation. Stereotact Funct Neurosurg 2020. [DOI: 10.1007/978-3-030-34906-6_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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8
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Määttä S, Säisänen L, Kallioniemi E, Lakka TA, Lintu N, Haapala EA, Koskenkorva P, Niskanen E, Ferreri F, Könönen M. Maturation changes the excitability and effective connectivity of the frontal lobe: A developmental TMS-EEG study. Hum Brain Mapp 2019; 40:2320-2335. [PMID: 30648321 DOI: 10.1002/hbm.24525] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 12/07/2018] [Accepted: 01/07/2019] [Indexed: 12/22/2022] Open
Abstract
The combination of transcranial magnetic stimulation with simultaneous electroencephalography (TMS-EEG) offers direct neurophysiological insight into excitability and connectivity within neural circuits. However, there have been few developmental TMS-EEG studies to date, and they all have focused on primary motor cortex stimulation. In the present study, we used navigated high-density TMS-EEG to investigate the maturation of the superior frontal cortex (dorsal premotor cortex [PMd]), which is involved in a broad range of motor and cognitive functions known to develop with age. We demonstrated that reactivity to frontal cortex TMS decreases with development. We also showed that although frontal cortex TMS elicits an equally complex TEP waveform in all age groups, the statistically significant between-group differences in the topography of the TMS-evoked peaks and differences in current density maps suggest changes in effective connectivity of the right PMd with maturation. More generally, our results indicate that direct study of the brain's excitability and effective connectivity via TMS-EEG co-registration can also be applied to pediatric populations outside the primary motor cortex, and may provide useful information for developmental studies and studies on developmental neuropsychiatric disorders.
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Affiliation(s)
- Sara Määttä
- Faculty of Health Sciences, Department of Clinical Neurophysiology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio Campus, Finland.,Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
| | - Laura Säisänen
- Faculty of Health Sciences, Department of Clinical Neurophysiology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio Campus, Finland.,Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
| | - Elisa Kallioniemi
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas
| | - Timo A Lakka
- Faculty of Health Sciences, Institute of Biomedicine, University of Eastern Finland, Kuopio Campus, Finland.,Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Kuopio, Finland.,Foundation for Research in Health Exercise and Nutrition, Kuopio Research Institute of Exercise Medicine, Kuopio, Finland
| | - Niina Lintu
- Faculty of Health Sciences, Institute of Biomedicine, University of Eastern Finland, Kuopio Campus, Finland
| | - Eero A Haapala
- Faculty of Health Sciences, Institute of Biomedicine, University of Eastern Finland, Kuopio Campus, Finland.,Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Päivi Koskenkorva
- Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland
| | - Eini Niskanen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Florinda Ferreri
- Department of Neuroscience, Unit of Neurology and Neurophysiology, University of Padua, Padua, Italy
| | - Mervi Könönen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.,Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland
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9
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Tremblay S, Rogasch NC, Premoli I, Blumberger DM, Casarotto S, Chen R, Di Lazzaro V, Farzan F, Ferrarelli F, Fitzgerald PB, Hui J, Ilmoniemi RJ, Kimiskidis VK, Kugiumtzis D, Lioumis P, Pascual-Leone A, Pellicciari MC, Rajji T, Thut G, Zomorrodi R, Ziemann U, Daskalakis ZJ. Clinical utility and prospective of TMS–EEG. Clin Neurophysiol 2019; 130:802-844. [DOI: 10.1016/j.clinph.2019.01.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/15/2022]
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10
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Darmani G, Ziemann U. Pharmacophysiology of TMS-evoked EEG potentials: A mini-review. Brain Stimul 2019; 12:829-831. [PMID: 30837122 DOI: 10.1016/j.brs.2019.02.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/21/2019] [Accepted: 02/22/2019] [Indexed: 11/15/2022] Open
Affiliation(s)
- Ghazaleh Darmani
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Ulf Ziemann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany.
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11
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Sidhu SK, Weavil JC, Thurston TS, Rosenberger D, Jessop JE, Wang E, Richardson RS, McNeil CJ, Amann M. Fatigue-related group III/IV muscle afferent feedback facilitates intracortical inhibition during locomotor exercise. J Physiol 2018; 596:4789-4801. [PMID: 30095164 DOI: 10.1113/jp276460] [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: 05/09/2018] [Accepted: 07/25/2018] [Indexed: 01/22/2023] Open
Abstract
KEY POINTS This study investigated the influence of group III/IV muscle afferents on corticospinal excitability during cycling exercise and focused on GABAB neuron-mediated inhibition as a potential underlying mechanism. The study provides novel evidence to demonstrate that group III/IV muscle afferent feedback facilitates inhibitory intracortical neurons during whole body exercise. Firing of these interneurons probably contributes to the development of central fatigue during physical activity. ABSTRACT We investigated the influence of group III/IV muscle afferents in determining corticospinal excitability during cycling exercise and focused on GABAB neuron-mediated inhibition as a potential underlying mechanism. Both under control conditions (CTRL) and with lumbar intrathecal fentanyl (FENT) impairing feedback from group III/IV leg muscle afferents, subjects (n = 11) cycled at a comparable vastus-lateralis EMG signal (∼0.26 mV) before (PRE; 100 W) and immediately after (POST; 90 ± 2 W) fatiguing constant-load cycling exercise (80% Wpeak; 221 ± 10 W; ∼8 min). During, PRE and POST cycling, single and paired-pulse (100 ms interstimulus interval) transcranial magnetic stimulations (TMS) were applied to elicit unconditioned and conditioned motor-evoked potentials (MEPs), respectively. To distinguish between cortical and spinal contributions to the MEPs, cervicomedullary stimulations (CMS) were used to elicit unconditioned (CMS only) and conditioned (TMS+CMS, 100 ms interval) cervicomedullary motor-evoked potentials (CMEPs). While unconditioned MEPs were unchanged from PRE to POST in CTRL, unconditioned CMEPs increased significantly, resulting in a decrease in unconditioned MEP/CMEP (P < 0.05). This paralleled a reduction in conditioned MEP (P < 0.05) and no change in conditioned CMEP. During FENT, unconditioned and conditioned MEPs and CMEPs were similar and comparable during PRE and POST (P > 0.2). These findings reveal that feedback from group III/IV muscle afferents innervating locomotor muscle decreases the excitability of the motor cortex during fatiguing cycling exercise. This impairment is, at least in part, determined by the facilitating effect of these sensory neurons on inhibitory GABAB intracortical interneurons.
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Affiliation(s)
- Simranjit K Sidhu
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Adelaide Medical School, Discipline of Physiology, The University of Adelaide, Australia
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | | | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Eivind Wang
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Chris J McNeil
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Markus Amann
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
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12
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Salavati B, Daskalakis ZJ, Zomorrodi R, Blumberger DM, Chen R, Pollock BG, Rajji TK. Pharmacological Modulation of Long-Term Potentiation-Like Activity in the Dorsolateral Prefrontal Cortex. Front Hum Neurosci 2018; 12:155. [PMID: 29740299 PMCID: PMC5928132 DOI: 10.3389/fnhum.2018.00155] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 04/05/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Long-term potentiation (LTP) depends on glutamatergic neurotransmission and is modulated by cholinergic, dopaminergic and GABAergic inputs. Paired associative stimulation (PAS) is a neurostimulation paradigm that, when combined with electroencephalography (EEG), assesses LTP-like activity (PAS-induced LTP) in the dorsolateral prefrontal cortex (DLPFC). Thus, we conducted a study to assess the role of cholinergic, dopaminergic, GABAergic and glutamatergic neurotransmission on PAS-induced LTP in the DLPFC. We hypothesized that increasing the dopaminergic tone with L-DOPA and the cholinergic tone with rivastigmine will enhance PAS-induced LTP, while increasing the GABAergic tone with baclofen and inhibiting glutamatergic neurotransmission with dextromethorphan will reduce it compared to placebo. Methods: In this randomized controlled, double-blind cross-over within-subject study, 12 healthy participants received five sessions of PAS to the DLPFC in a random order, each preceded by the administration of placebo or one of the four active drugs. PAS-induced LTP was assessed after each drug administration and compared to PAS-induced LTP after placebo. Results: As predicted, L-DOPA and rivastigmine resulted in enhanced PAS-induced LTP in the DLPFC and dextromethorphan inhibited it compared to placebo. In contrast, baclofen did not significantly suppress PAS-induced LTP compared to placebo. Conclusions: This study provides a novel approach to study DLPFC neuroplasticity and its modulation in patients with brain disorders that are associated with abnormalities in these neurochemical systems. This study was based on a single dose administration of each drug. Given that these drugs are typically administered chronically, future studies should assess the effects of chronic administration.
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Affiliation(s)
- Bahar Salavati
- Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Zafiris J Daskalakis
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Reza Zomorrodi
- Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Daniel M Blumberger
- Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Robert Chen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Bruce G Pollock
- Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Tarek K Rajji
- Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
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