1
|
Barbi C, Temesi J, Giuriato G, Laginestra FG, Martignon C, Moro T, Schena F, Venturelli M, Vernillo G. Skeletal muscle fiber type and TMS-induced muscle relaxation in unfatigued and fatigued knee-extensor muscles. Am J Physiol Regul Integr Comp Physiol 2024; 326:R438-R447. [PMID: 38525536 DOI: 10.1152/ajpregu.00174.2023] [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: 07/14/2023] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 03/26/2024]
Abstract
The force drop after transcranial magnetic stimulation (TMS) delivered to the motor cortex during voluntary muscle contractions could inform about muscle relaxation properties. Because of the physiological relation between skeletal muscle fiber-type distribution and size and muscle relaxation, TMS could be a noninvasive index of muscle relaxation in humans. By combining a noninvasive technique to record muscle relaxation in vivo (TMS) with the gold standard technique for muscle tissue sampling (muscle biopsy), we investigated the relation between TMS-induced muscle relaxation in unfatigued and fatigued states, and muscle fiber-type distribution and size. Sixteen participants (7F/9M) volunteered to participate. Maximal knee-extensor voluntary isometric contractions were performed with TMS before and after a 2-min sustained maximal voluntary isometric contraction. Vastus lateralis muscle tissue was obtained separately from the participants' dominant limb. Fiber type I distribution and relative cross-sectional area of fiber type I correlated with TMS-induced muscle relaxation at baseline (r = 0.67, adjusted P = 0.01; r = 0.74, adjusted P = 0.004, respectively) and normalized TMS-induced muscle relaxation as a percentage of baseline (r = 0.50, adjusted P = 0.049; r = 0.56, adjusted P = 0.031, respectively). The variance in the normalized peak relaxation rate at baseline (59.8%, P < 0.001) and in the fatigue resistance (23.0%, P = 0.035) were explained by the relative cross-sectional area of fiber type I to total fiber area. Fiber type I proportional area influences TMS-induced muscle relaxation, suggesting TMS as an alternative method to noninvasively inform about skeletal muscle relaxation properties.NEW & NOTEWORTHY Transcranial magnetic stimulation (TMS)-induced muscle relaxation reflects intrinsic muscle contractile properties by interrupting the drive from the central nervous system during voluntary muscle contractions. We showed that fiber type I proportional area influences the TMS-induced muscle relaxation, suggesting that TMS could be used for the noninvasive estimation of muscle relaxation in unfatigued and fatigued human muscles when the feasibility of more direct method to study relaxation properties (i.e., muscle biopsy) is restricted.
Collapse
Affiliation(s)
- Chiara Barbi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - John Temesi
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Gaia Giuriato
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Surgical, Medical and Dental Department of Morphological Sciences Related to Transplant, Oncology and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Camilla Martignon
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Tatiana Moro
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Federico Schena
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Massimo Venturelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Gianluca Vernillo
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
- Department of Social Sciences, University of Alberta, Camrose, Alberta, Canada
| |
Collapse
|
2
|
Giuriato G, Romanelli MG, Bartolini D, Vernillo G, Pedrinolla A, Moro T, Franchi M, Locatelli E, Andani ME, Laginestra FG, Barbi C, Aloisi GF, Cavedon V, Milanese C, Orlandi E, De Simone T, Fochi S, Patuzzo C, Malerba G, Fabene P, Donadelli M, Stabile AM, Pistilli A, Rende M, Galli F, Schena F, Venturelli M. Sex differences in neuromuscular and biological determinants of isometric maximal force. Acta Physiol (Oxf) 2024; 240:e14118. [PMID: 38385696 DOI: 10.1111/apha.14118] [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: 11/21/2023] [Revised: 01/29/2024] [Accepted: 02/09/2024] [Indexed: 02/23/2024]
Abstract
AIM Force expression is characterized by an interplay of biological and molecular determinants that are expected to differentiate males and females in terms of maximal performance. These include muscle characteristics (muscle size, fiber type, contractility), neuromuscular regulation (central and peripheral factors of force expression), and individual genetic factors (miRNAs and gene/protein expression). This research aims to comprehensively assess these physiological variables and their role as determinants of maximal force difference between sexes. METHODS Experimental evaluations include neuromuscular components of isometric contraction, intrinsic muscle characteristics (proteins and fiber type), and some biomarkers associated with muscle function (circulating miRNAs and gut microbiome) in 12 young and healthy males and 12 females. RESULTS Male strength superiority appears to stem primarily from muscle size while muscle fiber-type distribution plays a crucial role in contractile properties. Moderate-to-strong pooled correlations between these muscle parameters were established with specific circulating miRNAs, as well as muscle and plasma proteins. CONCLUSION Muscle size is crucial in explaining the differences in maximal voluntary isometric force generation between males and females with similar fiber type distribution. Potential physiological mechanisms are seen from associations between maximal force, skeletal muscle contractile properties, and biological markers.
Collapse
Affiliation(s)
- Gaia Giuriato
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Surgical, Medical and Dental Department of Morphological Sciences Related to Transplant, Oncology and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | - Maria Grazia Romanelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Desirée Bartolini
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Gianluca Vernillo
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
- Department of Social Sciences, University of Alberta - Augustana Campus, Camrose, Alberta, Canada
| | - Anna Pedrinolla
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Tatiana Moro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Martino Franchi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Elena Locatelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Mehran Emadi Andani
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Fabio Giuseppe Laginestra
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Anesthesiology, University of Utah, Utah, USA
| | - Chiara Barbi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Gloria Fiorini Aloisi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Valentina Cavedon
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Chiara Milanese
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Elisa Orlandi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Tonia De Simone
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Stefania Fochi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Cristina Patuzzo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Giovanni Malerba
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Paolo Fabene
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Massimo Donadelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Anna Maria Stabile
- Department of Medicine and Surgery, Section of Human Anatomy, Clinical and Forensic, School of Medicine, University of Perugia, Perugia, Italy
| | - Alessandra Pistilli
- Department of Medicine and Surgery, Section of Human Anatomy, Clinical and Forensic, School of Medicine, University of Perugia, Perugia, Italy
| | - Mario Rende
- Department of Medicine and Surgery, Section of Human Anatomy, Clinical and Forensic, School of Medicine, University of Perugia, Perugia, Italy
| | - Francesco Galli
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Federico Schena
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Massimo Venturelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Internal Medicine, University of Utah, Utah, USA
| |
Collapse
|
3
|
Barbi C, Vernillo G, Emadi Andani M, Giuriato G, Laginestra FG, Cavicchia A, Fiorini Aloisi G, Martignon C, Pedrinolla A, Schena F, Venturelli M. Comparison between conventional and neuronavigated strategies to assess corticospinal responsiveness in unfatigued and fatigued knee-extensor muscles. Neurosci Lett 2023:137351. [PMID: 37321388 DOI: 10.1016/j.neulet.2023.137351] [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: 12/06/2022] [Revised: 05/27/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023]
Abstract
In studying neuromuscular fatigability, researchers commonly use functional criteria to position and hold the transcranial magnetic stimulation (TMS) coil during testing sessions. This could influence the magnitude of corticospinal excitability and inhibition responses due to imprecise and unsteady positions of the coil. To reduce coil position and orientation variability, neuronavigated TMS (nTMS) could be used. We evaluated the accuracy of nTMS and a standardized function-guided procedure for maintaining TMS coil position both in unfatigued and fatigued knee extensors. Eighteen participants (10F/8M) volunteered in two identical and randomized sessions. Maximal and submaximal neuromuscular evaluations were performed with TMS three times before (PRE_1) and three times after (PRE_2) a 2 min resting session and one time immediately after (POST) a 2-min sustained maximal voluntary isometric contraction (MVIC). The located "hotspot" [the location that evoked the largest motor-evoked potential (MEP) responses in the rectus femoris] was maintained either with or without nTMS. MEP, silent period (SP) and the distance between the "hotspot" and the actual coil position were recorded. A time × contraction intensity × testing session × muscle interaction was not observed for MEP, SP, and distance. Bland-Altman plots presented adequate agreements for MEP and SP. Spatial accuracy of TMS coil position over the motor cortex did not influence corticospinal excitability and inhibition in unfatigued and fatigued knee extensors. The variability in MEP and SP responses may be due to spontaneous fluctuations in corticospinal excitability and inhibition, and it is not altered by the spatial stability of the stimulation point.
Collapse
Affiliation(s)
- C Barbi
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - G Vernillo
- Department of Biomedical Sciences for Health, University of Milan, Italy
| | - M Emadi Andani
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - G Giuriato
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - F G Laginestra
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - A Cavicchia
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - G Fiorini Aloisi
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - C Martignon
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - A Pedrinolla
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - F Schena
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - M Venturelli
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy.
| |
Collapse
|
4
|
Dempsey LM, Kavanagh JJ. Muscarinic acetylcholine activity modulates cortical silent period, but not motor evoked potentials, during muscle contractions. Exp Brain Res 2023; 241:1543-1553. [PMID: 37103494 DOI: 10.1007/s00221-023-06616-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 04/11/2023] [Indexed: 04/28/2023]
Abstract
This study used transcranial magnetic stimulation (TMS) to determine if muscarinic receptor blockade affects muscle responses during voluntary contractions. Motor evoked potentials (MEPs) were recorded from biceps brachii in 10 subjects (age: 23 ± 2) during 10%, 25%, 50%, 75%, and 100% maximal voluntary contractions (MVCs). Each contraction intensity was examined under non-fatigued and fatigued conditions. All measurements were obtained post-ingestion of 25 mg promethazine or placebo. MEP area and the duration of the TMS-evoked silent period (SP) were calculated for all contractions. No drug-related differences were detected for MEP area during non-fatigued or fatigued contractions. A main effect of drug was detected for the SP (p = 0.019) where promethazine increased SP duration by an average of 0.023 [Formula: see text] 0.015 s. This drug effect was only identified for the unfatigued contractions and not following the sustained fatiguing contractions (p = 0.105). The cholinergic system does not influence corticospinal excitability during voluntary muscle contractions, but instead affects neural circuits associated with the TMS-evoked SP. Given the prevalence of cholinergic properties in prescription and over-the-counter medications, the current study enhances our understanding of mechanisms that may contribute to motor side-effects.
Collapse
Affiliation(s)
- Lisa M Dempsey
- Menzies Health Institute Queensland, Griffith University, Southport, Australia.
- School of Allied Health Sciences, Griffith University, Gold Coast Campus, Southport, QLD, 4222, Australia.
| | - Justin J Kavanagh
- Menzies Health Institute Queensland, Griffith University, Southport, Australia
| |
Collapse
|
5
|
Vernillo G, Barbi C, Temesi J, Giuriato G, Giuseppe Laginestra F, Martignon C, Schena F, Venturelli M. Reliability of relaxation properties of knee-extensor muscles induced by transcranial magnetic stimulation. Neurosci Lett 2022; 782:136694. [DOI: 10.1016/j.neulet.2022.136694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
|
6
|
Temesi J, Besson T, Parent A, Singh B, Martin V, Brownstein CG, Espeit L, Royer N, Rimaud D, Lapole T, Féasson L, Millet GY. Effect of race distance on performance fatigability in male trail and ultra-trail runners. Scand J Med Sci Sports 2021; 31:1809-1821. [PMID: 34170574 DOI: 10.1111/sms.14004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 05/31/2021] [Indexed: 11/28/2022]
Abstract
The etiology of changes in lower-limb neuromuscular function, especially to the central nervous system, may be affected by exercise duration. Direct evidence is lacking as few studies have directly compared different race distances. This study aimed to investigate the etiology of deficits in neuromuscular function following short versus long trail-running races. Thirty-two male trail runners completed one of five trail-running races as LONG (>100 km) or SHORT (<60 km). Pre- and post-race, maximal voluntary contraction (MVC) torque and evoked responses to electrical nerve stimulation during MVCs and at rest were used to assess voluntary activation and muscle contractile properties of knee-extensor (KE) and plantar-flexor (PF) muscles. Transcranial magnetic stimulation (TMS) was used to assess evoked responses and corticospinal excitability in maximal and submaximal KE contractions. Race distance correlated with KE MVC (ρ = -0.556) and twitch (ρ = -0.521) torque decreases (p ≤ .003). KE twitch torque decreased more in LONG (-28 ± 14%) than SHORT (-14 ± 10%, p = .005); however, KE MVC time × distance interaction was not significant (p = .073). No differences between LONG and SHORT for PF MVC or twitch torque were observed. Maximal voluntary activation decreased similarly in LONG and SHORT in both muscle groups (p ≥ .637). TMS-elicited silent period decreased in LONG (p = .021) but not SHORT (p = .912). Greater muscle contractile property impairment in longer races, not central perturbations, contributed to the correlation between KE MVC loss and race distance. Conversely, PF fatigability was unaffected by race distance.
Collapse
Affiliation(s)
- John Temesi
- Faculty of Health & Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Thibault Besson
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France
| | - Audrey Parent
- Department of Biological Sciences, Université du Québec à Montréal (UQÀM), Montreal, QC, Canada.,CHU Sainte-Justine (CRME), Montreal, QC, Canada
| | - Benjamin Singh
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France
| | - Vincent Martin
- AME2P, Université Clermont Auvergne, Clermont-Ferrand, France.,Institut Universitaire de France (IUF), Paris, France
| | - Callum G Brownstein
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France
| | - Loïc Espeit
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France
| | - Nicolas Royer
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France
| | - Diana Rimaud
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France
| | - Thomas Lapole
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France
| | - Léonard Féasson
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France.,Myology Unit, Referent Center of Rare Neuromuscular Diseases, Euro-NmD, Universitiy Hospital of Saint-Etienne, Saint-Etienne, France
| | - Guillaume Y Millet
- Inter-University Laboratory of Human Movement Biology, EA 7424, Université de Lyon, UJM-Saint-Etienne, Saint-Etienne, France.,Institut Universitaire de France (IUF), Paris, France
| |
Collapse
|
7
|
Zeugin D, Ionta S. Anatomo-Functional Origins of the Cortical Silent Period: Spotlight on the Basal Ganglia. Brain Sci 2021; 11:705. [PMID: 34071742 PMCID: PMC8227635 DOI: 10.3390/brainsci11060705] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/17/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
The so-called cortical silent period (CSP) refers to the temporary interruption of electromyographic signal from a muscle following a motor-evoked potential (MEP) triggered by transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). The neurophysiological origins of the CSP are debated. Previous evidence suggests that both spinal and cortical mechanisms may account for the duration of the CSP. However, contextual factors such as cortical fatigue, experimental procedures, attentional load, as well as neuropathology can also influence the CSP duration. The present paper summarizes the most relevant evidence on the mechanisms underlying the duration of the CSP, with a particular focus on the central role of the basal ganglia in the "direct" (excitatory), "indirect" (inhibitory), and "hyperdirect" cortico-subcortical pathways to manage cortical motor inhibition. We propose new methods of interpretation of the CSP related, at least partially, to the inhibitory hyperdirect and indirect pathways in the basal ganglia. This view may help to explain the respective shortening and lengthening of the CSP in various neurological disorders. Shedding light on the complexity of the CSP's origins, the present review aims at constituting a reference for future work in fundamental research, technological development, and clinical settings.
Collapse
Affiliation(s)
| | - Silvio Ionta
- Sensory-Motor Laboratory (SeMoLa), Jules-Gonin Eye Hospital/Fondation Asile des Aveugles, Department of Ophthalmology, University of Lausanne, 1002 Lausanne, Switzerland
| |
Collapse
|
8
|
Hupfeld KE, Swanson CW, Fling BW, Seidler RD. TMS-induced silent periods: A review of methods and call for consistency. J Neurosci Methods 2020; 346:108950. [PMID: 32971133 PMCID: PMC8276277 DOI: 10.1016/j.jneumeth.2020.108950] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/24/2020] [Accepted: 09/15/2020] [Indexed: 12/31/2022]
Abstract
Transcranial magnetic stimulation (TMS)-induced silent periods provide an in vivo measure of human motor cortical inhibitory function. Cortical silent periods (cSP, also sometimes referred to as contralateral silent periods) and ipsilateral silent periods (iSP) may change with advancing age and disease and can provide insight into cortical control of the motor system. The majority of past silent period work has implemented largely varying methodology, sometimes including subjective analyses and incomplete methods descriptions. This limits reproducibility of silent period work and hampers comparisons of silent period measures across studies. Here, we discuss methodological differences in past silent period work, highlighting how these choices affect silent period outcome measures. We also outline challenges and possible solutions for measuring silent periods in the unique case of the lower limbs. Finally, we provide comprehensive recommendations for collection, analysis, and reporting of future silent period studies.
Collapse
Affiliation(s)
- K E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - C W Swanson
- Department of Health & Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - B W Fling
- Department of Health & Exercise Science, Colorado State University, Fort Collins, CO, USA; Molecular, Cellular, and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO, USA
| | - R D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology, University of Florida, Gainesville, FL, USA.
| |
Collapse
|
9
|
Vernillo G, Khassetarash A, Millet GY, Temesi J. Use of transcranial magnetic stimulation to assess relaxation rates in unfatigued and fatigued knee-extensor muscles. Exp Brain Res 2020; 239:205-216. [PMID: 33140192 PMCID: PMC7884370 DOI: 10.1007/s00221-020-05921-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 09/04/2020] [Indexed: 11/29/2022]
Abstract
We examined whether transcranial magnetic stimulation (TMS) delivered to the motor cortex allows assessment of muscle relaxation rates in unfatigued and fatigued knee extensors (KE). We assessed the ability of this technique to measure time course of fatigue-induced changes in muscle relaxation rate and compared relaxation rate from resting twitches evoked by femoral nerve stimulation. Twelve healthy men performed maximal voluntary isometric contractions (MVC) twice before (PRE) and once at the end of a 2-min KE MVC and five more times within 8 min during recovery. Relative (intraclass correlation coefficient; ICC2,1) and absolute (repeatability coefficient) reliability and variability (coefficient of variation) were assessed. Time course of fatigue-induced changes in muscle relaxation rate was tested with generalized estimating equations. In unfatigued KE, peak relaxation rate coefficient of variation and repeatability coefficient were similar for both techniques. Mean (95% CI) ICC2,1 for peak relaxation rates were 0.933 (0.724–0.982) and 0.889 (0.603–0.968) for TMS and femoral nerve stimulation, respectively. TMS-induced normalized muscle relaxation rate was − 11.5 ± 2.5 s−1 at PRE, decreased to − 6.9 ± 1.2 s−1 (− 37 ± 17%, P < 0.001), and recovered by 2 min post-exercise. Normalized peak relaxation rate for resting twitch did not show a fatigue-induced change. During fatiguing KE exercise, the change in muscle relaxation rate as determined by the two techniques was different. TMS provides reliable values of muscle relaxation rates. Furthermore, it is sufficiently sensitive and more appropriate than the resting twitch evoked by femoral nerve stimulation to reveal fatigue-induced changes in KE.
Collapse
Affiliation(s)
- Gianluca Vernillo
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Department of Biomedical Sciences for Health, Università Degli Studi di Milano, Milan, Italy
| | - Arash Khassetarash
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Guillaume Y Millet
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,University of Lyon, UJM Saint-Etienne, Inter-University Laboratory of Human Movement Biology, EA 7424), 42023, Saint-Etienne, France.,Institut Universitaire de France (IUF), Paris, France
| | - John Temesi
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada. .,Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK.
| |
Collapse
|
10
|
Sustained Maximal Voluntary Contractions Elicit Different Neurophysiological Responses in Upper- and Lower-Limb Muscles in Men. Neuroscience 2019; 422:88-98. [DOI: 10.1016/j.neuroscience.2019.09.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 11/20/2022]
|
11
|
Le Roux-Mallouf T, Laurent J, Besset D, Marillier M, Larribaut J, Belaidi E, Corne C, Doutreleau S, Verges S. Effects of acute nitric oxide precursor intake on peripheral and central fatigue during knee extensions in healthy men. Exp Physiol 2019; 104:1100-1114. [PMID: 31004378 DOI: 10.1113/ep087493] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/18/2019] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the effect of acute NO precursor intake on vascular function, muscle and cerebral oxygenation and peripheral and central neuromuscular fatigue during knee-extension exercise? What is the main finding and its importance? Acute NO precursor ingestion increases the plasma concentrations of NO precursors (nitrate, arginine and citrulline) and enhances post-ischaemic vasodilatation, but has no significant effect on muscle and cerebral oxygenation, peripheral and central mechanisms of neuromuscular fatigue and, consequently, does not improve exercise performance. ABSTRACT Nitric oxide (NO) plays an important role in matching blood flow to oxygen demand in the brain and contracting muscles during exercise. Previous studies have shown that increasing NO bioavailability can improve muscle function. The aim of this study was to assess the effect of acute NO precursor intake on muscle and cerebral oxygenation and on peripheral and central neuromuscular fatigue during exercise. In four experimental sessions, 15 healthy men performed a thigh ischaemia-reperfusion test followed by submaximal isometric knee extensions (5 s on-4 s off; 45% of maximal voluntary contraction) until task failure. In each session, subjects drank a nitrate-rich beetroot juice containing 520 mg nitrate (N), N and citrulline (6 g; N+C), N and arginine (6 g; N+A) or a placebo (PLA). Prefrontal cortex and quadriceps near-infrared spectroscopy parameters were monitored continuously. Transcranial magnetic stimulation and femoral nerve electrical stimulation were used to assess central and peripheral determinants of fatigue. The post-ischaemic increase in thigh blood total haemoglobin concentration was larger in N (10.1 ± 3.7 mmol) and N+C (10.9 ± 3.3 mmol) compared with PLA (8.2 ± 2.7 mmol; P < 0.05). Nitric oxide precursors had no significant effect on muscle and cerebral oxygenation or on peripheral and central mechanisms of neuromuscular fatigue during exercise. The total number of knee extensions did not differ between sessions (N, 71.9 ± 33.2; N+A, 73.3 ± 39.4; N+C, 74.6 ± 34.0; PLA, 71.8 ± 39.9; P > 0.05). In contrast to the post-ischaemic hyperaemic response, NO bioavailability in healthy subjects might not be the limiting factor for tissue perfusion and oxygenation during submaximal knee extensions to task failure.
Collapse
Affiliation(s)
| | - Julien Laurent
- Laboratoire HP2 (U1042 INSERM), Université, Grenoble Alpes, Grenoble, France
| | - Dimitri Besset
- Laboratoire HP2 (U1042 INSERM), Université, Grenoble Alpes, Grenoble, France
| | - Mathieu Marillier
- Laboratoire HP2 (U1042 INSERM), Université, Grenoble Alpes, Grenoble, France
| | - Julie Larribaut
- Laboratoire HP2 (U1042 INSERM), Université, Grenoble Alpes, Grenoble, France
| | - Elise Belaidi
- Laboratoire HP2 (U1042 INSERM), Université, Grenoble Alpes, Grenoble, France
| | - Christelle Corne
- Inherited Metabolic Disease Laboratory, Department of Biochemistry, Molecular and Environmental Toxicology Biology, Biology and Pathology Institute, Hôpital Michallon, Grenoble, France
| | - Stéphane Doutreleau
- Laboratoire HP2 (U1042 INSERM), Université, Grenoble Alpes, Grenoble, France.,Sport and Pathologies Unit, Grenoble Alpes University Hospital, Hôpital Michallon, Grenoble, France
| | - Samuel Verges
- Laboratoire HP2 (U1042 INSERM), Université, Grenoble Alpes, Grenoble, France.,Sport and Pathologies Unit, Grenoble Alpes University Hospital, Hôpital Michallon, Grenoble, France
| |
Collapse
|
12
|
Škarabot J, Mesquita RNO, Brownstein CG, Ansdell P. Myths and Methodologies: How loud is the story told by the transcranial magnetic stimulation-evoked silent period? Exp Physiol 2019; 104:635-642. [PMID: 30830992 DOI: 10.1113/ep087557] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 03/01/2019] [Indexed: 12/13/2022]
Abstract
NEW FINDINGS What is the topic of this review? The origin, interpretation and methodological constraints of the silent period induced by transcranial magnetic stimulation are reviewed. What advances does it highlight? The silent period is generated by both cortical and spinal mechanisms. Therefore, it seems inappropriate to preface silent period with 'cortical' unless additional measures are taken. Owing to many confounding variables, a standardized approach to the silent period measurement cannot be suggested. Rather, recommendations of best practice are provided based on the available evidence and the context of the research question. ABSTRACT Transcranial magnetic stimulation (TMS) of the motor cortex evokes a response in the muscle that can be recorded via electromyography (EMG). One component of this response, when elicited during a voluntary contraction, is a period of EMG silence, termed the silent period (SP), which follows a motor evoked potential (MEP). Modulation of SP duration was long thought to reflect the degree of intracortical inhibition. However, the evidence presented in this review suggests that both cortical and spinal mechanisms contribute to generation of the SP, which makes prefacing SP with 'cortical' misleading. Further investigations with multi-methodological approaches, such as TMS-EEG coupling or interaction of TMS with neuroactive drugs, are needed to make such inferences with greater confidence. A multitude of methodological factors can influence the SP and thus confound the interpretation of this measure; namely, background muscle activity, instructions given to the participant, stimulus intensity and the size of the MEP preceding the SP, and the approach to analysis. A systematic understanding of how the confounding factors influence the interpretation of SP is lacking, which makes standardization of the methodology difficult to conceptualize. Instead, the methodology should be guided through the lens of the research question and the population studied, ensuring greater reproducibility, repeatability and comparability of data sets. Recommendations are provided for the best practice within a given context of the experimental design.
Collapse
Affiliation(s)
- Jakob Škarabot
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Ricardo N O Mesquita
- Faculty of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Callum G Brownstein
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK.,Univ Lyon, UJM Saint-Etienne, Laboratoire Interuniversitaire de Biologie de la Motricité, Saint-Étienne, France
| | - Paul Ansdell
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| |
Collapse
|
13
|
MARILLIER MATHIEU, GRUET MATHIEU, BAILLIEUL SÉBASTIEN, LE ROUX MALLOUF THIBAULT, WUYAM BERNARD, TAMISIER RENAUD, LEVY PATRICK, PEPIN JEANLOUIS, VERGES SAMUEL. Neuromuscular Dysfunction and Cortical Impairment in Sleep Apnea Syndrome. Med Sci Sports Exerc 2018; 50:1529-1539. [DOI: 10.1249/mss.0000000000001625] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
14
|
VERNILLO GIANLUCA, TEMESI JOHN, MARTIN MATTHIEU, MILLET GUILLAUMEY. Mechanisms of Fatigue and Recovery in Upper versus Lower Limbs in Men. Med Sci Sports Exerc 2018; 50:334-343. [DOI: 10.1249/mss.0000000000001445] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
15
|
Effects of high-altitude exposure on supraspinal fatigue and corticospinal excitability and inhibition. Eur J Appl Physiol 2017. [PMID: 28647868 DOI: 10.1007/s00421-017-3669-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE While acute hypoxic exposure enhances exercise-induced central fatigue and can alter corticospinal excitability and inhibition, the effect of prolonged hypoxic exposure on these parameters remains to be clarified. We hypothesized that 5 days of altitude exposure would (i) normalize exercise-induced supraspinal fatigue during isolated muscle exercise to sea level (SL) values and (ii) increase corticospinal excitability and inhibition. METHODS Eleven male subjects performed intermittent isometric elbow flexions at 50% of maximal voluntary contraction to task failure at SL and after 1 (D1) and 5 (D5) days at 4350 m. Transcranial magnetic stimulation and peripheral electrical stimulation were used to assess supraspinal and peripheral fatigues. Pre-frontal cortex and biceps brachii oxygenation was monitored by near-infrared spectroscopy. RESULTS Exercise duration was not statistically different between SL (1095 ± 562 s), D1 (1132 ± 516 s), and D5 (1440 ± 689 s). No significant differences were found between the three experimental conditions in maximal voluntary activation declines at task failure (SL -16.8 ± 9.5%; D1 -25.5 ± 11.2%; D5 -21.8 ± 7.0%; p > 0.05). Exercise-induced peripheral fatigue was larger at D5 versus SL (100 Hz doublet at task failure: -58.8 ± 16.6 versus -41.8 ± 20.1%; p < 0.05). Corticospinal excitability at 50% maximal voluntary contraction was lower at D5 versus SL (brachioradialis p < 0.05, biceps brachii p = 0.055). Cortical silent periods were shorter at SL versus D1 and D5 (p < 0.05). CONCLUSIONS The present results show similar patterns of supraspinal fatigue development during isometric elbow flexions at SL and after 1 and 5 days at high altitude, despite larger amount of peripheral fatigue at D5, lowered corticospinal excitability and enhanced corticospinal inhibition at altitude.
Collapse
|
16
|
Temesi J, Ly SN, Millet GY. Reliability of single- and paired-pulse transcranial magnetic stimulation for the assessment of knee extensor muscle function. J Neurol Sci 2017; 375:442-449. [PMID: 28320184 DOI: 10.1016/j.jns.2017.02.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/25/2017] [Accepted: 02/15/2017] [Indexed: 11/17/2022]
Abstract
This study examined inter-session and intra-session transcranial magnetic stimulation (TMS) reliability at two test stimulus intensities in the knee extensors. Strong and weak TMS was delivered via single- and paired- (3-ms and 100-ms inter-stimulus interval) pulses on the same day and different days. All stimuli were delivered during isometric contractions of the knee extensors at 20% of maximal voluntary force. Motor-evoked potentials (MEP) were assessed in quadriceps femoris muscles. Relative (intra-class correlation coefficient, ICC) and absolute (standard error of measurement, SEM) reliability and variability (coefficient of variation) were assessed. MEPs elicited by strong and weak single-pulse TMS had excellent relative reliability in all muscles as did weak short-interval and strong long-interval paired-pulse TMS (all ICC>0.75). Conversely, relative reliability of strong short-interval and weak long-interval paired-pulse TMS was lower (ICC: 0.34-0.83 and 0.22-0.97, respectively). MEP size variability was lower (P<0.05) and SEM comparable or lower in strong compared to weak TMS conditions. These results suggest single- and paired-pulse TMS at both strong and weak intensities are generally reliable in the knee extensors. Strong (or both strong and weak) single-pulse TMS is recommended. The results indicate using weak test pulses for short-interval and strong test pulses for long-interval paired-pulse TMS are recommended.
Collapse
Affiliation(s)
- John Temesi
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Sandy N Ly
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Guillaume Y Millet
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
| |
Collapse
|
17
|
Modulation of inhibitory corticospinal circuits induced by a nocebo procedure in motor performance. PLoS One 2015; 10:e0125223. [PMID: 25923533 PMCID: PMC4414618 DOI: 10.1371/journal.pone.0125223] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/16/2015] [Indexed: 11/19/2022] Open
Abstract
As recently demonstrated, a placebo procedure in motor performance increases force production and changes the excitability of the corticospinal system, by enhancing the amplitude of the motor evoked potentials (MEP) and reducing the duration of the cortical silent period (CSP). However, it is not clear whether these neurophysiological changes are related to the behavioural outcome (increased force) or to a general effect of expectation. To clarify this, we investigated the nocebo effect, in which the induced expectation decreases force production. Two groups of healthy volunteers (experimental and control) performed a motor task by pressing a piston with the right index finger. To induce a nocebo effect in the experimental group, low frequency transcutaneous electrical nerve stimulation (TENS) was applied over the index finger with instructions of its detrimental effects on force. To condition the subjects, the visual feedback on their force level was surreptitiously reduced after TENS. Results showed that the experimental group reduced the force, felt weaker and expected a worse performance than the control group, who was not suggested about TENS. By applying transcranial magnetic stimulation over the primary motor cortex, we found that while MEP amplitude remained stable throughout the procedure in both groups, the CSP duration was shorter in the experimental group after the nocebo procedure. The CSP reduction resembled previous findings on the placebo effect, suggesting that expectation of change in performance diminishes the inhibitory activation of the primary motor cortex, independently of the behavioural outcome.
Collapse
|
18
|
Pageaux B, Angius L, Hopker JG, Lepers R, Marcora SM. Central alterations of neuromuscular function and feedback from group III-IV muscle afferents following exhaustive high-intensity one-leg dynamic exercise. Am J Physiol Regul Integr Comp Physiol 2015; 308:R1008-20. [PMID: 25855308 DOI: 10.1152/ajpregu.00280.2014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 04/07/2015] [Indexed: 11/22/2022]
Abstract
The aims of this investigation were to describe the central alterations of neuromuscular function induced by exhaustive high-intensity one-leg dynamic exercise (OLDE, study 1) and to indirectly quantify feedback from group III-IV muscle afferents via muscle occlusion (MO, study 2) in healthy adult male humans. We hypothesized that these central alterations and their recovery are associated with changes in afferent feedback. Both studies consisted of two time-to-exhaustion tests at 85% peak power output. In study 1, voluntary activation level (VAL), M-wave, cervicomedullary motor evoked potential (CMEP), motor evoked potential (MEP), and MEP cortical silent period (CSP) of the knee extensor muscles were measured. In study 2, mean arterial pressure (MAP) and leg muscle pain were measured during MO. Measurements were performed preexercise, at exhaustion, and after 3 min recovery. Compared with preexercise values, VAL was lower at exhaustion (-13 ± 13%, P < 0.05) and after 3 min of recovery (-6 ± 6%, P = 0.05). CMEP area/M area was lower at exhaustion (-38 ± 13%, P < 0.01) and recovered after 3 min. MEP area/M area was higher at exhaustion (+25 ± 27%, P < 0.01) and after 3 min of recovery (+17 ± 20%, P < 0.01). CSP was higher (+19 ± 9%, P < 0.01) only at exhaustion and recovered after 3 min. Markers of afferent feedback (MAP and leg muscle pain during MO) were significantly higher only at exhaustion. These findings suggest that the alterations in spinal excitability and CSP induced by high-intensity OLDE are associated with an increase in afferent feedback at exhaustion, whereas central fatigue does not fully recover even when significant afferent feedback is no longer present.
Collapse
Affiliation(s)
- Benjamin Pageaux
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
| | - Luca Angius
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
| | - James G Hopker
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
| | - Romuald Lepers
- Laboratoire Institut national de la santé et de la recherche médical U1093, Université de Bourgogne, Faculté des Sciences du Sports, UFR STAPS, Dijon, France
| | - Samuele M Marcora
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
| |
Collapse
|
19
|
Zghal F, Cottin F, Kenoun I, Rebaï H, Moalla W, Dogui M, Tabka Z, Martin V. Improved tolerance of peripheral fatigue by the central nervous system after endurance training. Eur J Appl Physiol 2015; 115:1401-15. [PMID: 25681110 DOI: 10.1007/s00421-015-3123-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 02/03/2015] [Indexed: 11/28/2022]
Abstract
PURPOSE The purposes of this study were to evaluate the effect of endurance training on central fatigue development and recovery. METHODS A control group was compared to a training group, which followed an 8-week endurance-training program, consisting in low-force concentric and isometric contractions. Before (PRE) and after (POST) the training period, neuromuscular function of the knee extensor (KE) muscles was evaluated before, immediately after and during 33 min after an exhausting submaximal isometric task at 15 % of the maximal voluntary contraction (MVC) force. After training, the trained group performed another test at iso-time, i.e., with the task maintained until the duration completed before training was matched (POST2). The evaluation of neuromuscular function consisted in the determination of the voluntary activation level during MVCs, from peripheral nerve electrical (VAPNS) and transcranial magnetic stimulations (VATMS). The amplitude of the potentiated twitch (Pt), the evoked [motor evoked potentials, cortical silent period (CSP)] and voluntary EMG activities were also recorded on the KE muscles. RESULTS Before training, the isometric task induced significant reductions of VAPNS, VATMS and Pt, and an increased CSP. The training period induced a threefold increase of exercise duration, delayed central fatigue appearance, as illustrated by the absence of modification of VAPNS, VATMS and CSP after POST2. At POST, central fatigue magnitude and recovery were not modified but Pt reduction was greater. CONCLUSION These results suggest that central fatigue partially adapts to endurance training. This adaptation principally translates into improved tolerance of peripheral fatigue by the central nervous system.
Collapse
Affiliation(s)
- F Zghal
- UBIAE (INSERM U902), Faculty of Sport Sciences, Val d'Essonne University, Evry, France
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Does the region of epileptogenicity influence the pattern of change in cortical excitability? Clin Neurophysiol 2014; 126:249-56. [PMID: 25002368 DOI: 10.1016/j.clinph.2014.05.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 05/11/2014] [Accepted: 05/14/2014] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To investigate whether cortical excitability measures on transcranial magnetic stimulation (TMS) differed between groups of patients with different focal epilepsy syndromes. METHODS 85 Patients with focal epilepsy syndromes divided into temporal and extra-temporal lobe epilepsy were studied. The cohorts were further divided into drug naïve-new onset, refractory and seizure free groups. Motor threshold (MT) and paired pulse TMS at short (2, 5, 10, 15 ms) and long (100-300 ms) interstimulus intervals (ISIs) were measured. Results were compared to those of 20 controls. RESULTS Cortical excitability was higher at 2 & 5 ms and 250, 300 ms ISIs (p<0.01) in focal epilepsy syndromes compared to controls however significant inter-hemispheric differences in MT and the same ISIs were only seen in the drug naïve state early at onset and were much more prominent in temporal lobe epilepsy. CONCLUSION Disturbances in cortical excitability are more confined to the affected hemisphere in temporal lobe epilepsy but only early at onset in the drug naïve state. SIGNIFICANCE Group TMS studies show that cortical excitability measures are different in temporal lobe epilepsy and can be distinguished from other focal epilepsies early at onset in the drug naïve state. Further studies are needed to determine whether these results can be applied clinically as the utility of TMS in distinguishing between epilepsy syndromes at an individual level remains to be determined.
Collapse
|
21
|
Gruet M, Temesi J, Rupp T, Levy P, Verges S, Millet GY. Dynamics of corticospinal changes during and after high-intensity quadriceps exercise. Exp Physiol 2014; 99:1053-64. [PMID: 24907029 DOI: 10.1113/expphysiol.2014.078840] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study tested the hypothesis that during fatiguing quadriceps exercise, supraspinal fatigue develops late, is associated with both increased corticospinal excitability and inhibition and recovers quickly. Eight subjects performed 20 s contractions [15 s at 50% maximal voluntary contraction (MVC) followed by 5 s MVC] separated by a 10 s rest period until task failure. Transcranial magnetic stimulation (TMS) and electrical femoral nerve stimulation (PNS) were delivered ∼ 2 s apart during 50% MVC, during MVC and after MVC in relaxed muscle. Voluntary activation was assessed by TMS (VATMS) immediately before and after exercise and then three times over a 6 min recovery period. During exercise, MVC and twitch force evoked by PNS in relaxed muscle decreased progressively to 48 ± 8 and 36 ± 16% of control values, respectively (both P < 0.01). Significant changes in voluntary activation assessed by PNS and twitch evoked by TMS during MVC were observed during the last quarter of exercise only (from 96.4 ± 1.7 to 86 ± 13%, P = 0.03 and from 0.76 ± 0.8 to 4.9 ± 4.7% MVC, P = 0.02, from baseline to task failure, respectively). The TMS-induced silent period increased linearly during both MVC (by ∼ 79 ms) and 50% MVC (by ∼ 63 ms; both P < 0.01). Motor-evoked potential amplitude did not change during the protocol at any force levels. Both silent period and VATMS recovered within 2 min postexercise, whereas MVC and twitch force evoked by PNS in relaxed muscle recovered to only 84 ± 9 and 73 ± 17% of control values 6 min after exercise, respectively. In conclusion, high-intensity single-joint quadriceps exercise induces supraspinal fatigue near task failure, with increased intracortical inhibition and, in contrast to previous upper-limb results, unchanged corticospinal excitability. These changes recover rapidly after task failure, emphasizing the need to measure corticospinal adaptations immediately at task failure to avoid underestimation of exercise-induced corticospinal changes.
Collapse
Affiliation(s)
- Mathieu Gruet
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France Laboratoire Motricité Humaine, Education, Sport, Santé, Université de Toulon, France
| | - John Temesi
- Université de Lyon, F-42023, Saint-Etienne, France Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas Rupp
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France
| | - Patrick Levy
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France
| | - Samuel Verges
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France
| | - Guillaume Y Millet
- INSERM, U1042, F-38000, Grenoble, France Université de Lyon, F-42023, Saint-Etienne, France Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
22
|
Buharin VE, Butler AJ, Shinohara M. Motor cortical disinhibition with baroreceptor unloading induced by orthostatic stress. J Neurophysiol 2014; 111:2656-64. [PMID: 24671536 DOI: 10.1152/jn.00778.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unloading of the baroreceptors due to orthostatic stress increases corticospinal excitability. The purpose of this study was to examine the effects of baroreceptor unloading due to orthostatic stress on intracortical excitatory and inhibitory pathways in the motor cortex. With transcranial magnetic stimulation, measures of intracortical excitability for a hand muscle were tested on 2 days in healthy young adults. Lower body negative pressure (LBNP) of 40 mmHg was applied during one of the days and not during the Control day. During application of LBNP heart rate and the low-frequency component of heart rate variability increased, while mean arterial blood pressure was maintained. In the resting state, LBNP decreased short-interval intracortical inhibition (SICI) and had no effect on intracortical facilitation (ICF) or short-interval intracortical facilitation (SICF) compared with the Control day. During isometric contraction, no effects of LBNP were observed on tested measures of intracortical excitability including SICI, SICF, and cortical silent period. It was concluded that baroreceptor unloading due to orthostatic stress results in diminished intracortical inhibition, at least in the resting muscle.
Collapse
Affiliation(s)
- Vasiliy E Buharin
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, Georgia
| | - Andrew J Butler
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, Georgia; Department of Physical Therapy, Georgia State University, Atlanta, Georgia; and Rehabilitation R&D Center of Excellence, Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia
| | - Minoru Shinohara
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, Georgia; Rehabilitation R&D Center of Excellence, Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia
| |
Collapse
|
23
|
Gruet M, Temesi J, Rupp T, Millet GY, Verges S. Effect of different approaches to target force on transcranial magnetic stimulation responses. Muscle Nerve 2013; 48:430-2. [DOI: 10.1002/mus.23786] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Mathieu Gruet
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
| | - John Temesi
- Laboratoire LPE; Université de Lyon; Saint-Etienne France
| | - Thomas Rupp
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
| | | | - Samuel Verges
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
| |
Collapse
|
24
|
Kačar A, Filipović S, Kresojević N, Milanović S, Ljubisavljević M, Kostić V, Rothwell J. History of exposure to dopaminergic medication does not affect motor cortex plasticity and excitability in Parkinson’s disease. Clin Neurophysiol 2013; 124:697-707. [DOI: 10.1016/j.clinph.2012.09.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 09/04/2012] [Accepted: 09/06/2012] [Indexed: 10/27/2022]
|
25
|
Gruet M, Temesi J, Rupp T, Levy P, Millet G, Verges S. Stimulation of the motor cortex and corticospinal tract to assess human muscle fatigue. Neuroscience 2013; 231:384-99. [DOI: 10.1016/j.neuroscience.2012.10.058] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/10/2012] [Accepted: 10/29/2012] [Indexed: 10/27/2022]
|
26
|
Ziemann U. Pharmaco-transcranial magnetic stimulation studies of motor excitability. HANDBOOK OF CLINICAL NEUROLOGY 2013; 116:387-397. [PMID: 24112911 DOI: 10.1016/b978-0-444-53497-2.00032-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Application of a single dose of a central nervous system (CNS) active drug with a defined single mode of action has been proven useful to explore and characterize the pharmacophysiological properties of transcranial magnetic stimulation (TMS) measures of motor cortical and corticospinal excitability in humans. With this pharmaco-TMS approach, it was demonstrated that different TMS measures reflect axon excitability (motor threshold), or inhibitory (cortical silent period, short-interval intracortical inhibition, long-interval intracortical inhibition, short-latency afferent inhibition) or excitatory synaptic excitability (motor evoked potential amplitude, intracortical facilitation, short-interval intracortical facilitation) of distinct neuronal elements in the CNS. Pharmaco-TMS has opened an exciting window into human cortical physiology. The array of pharmacophysiologically well defined TMS measures is now used by neurologists, psychiatrists, and clinical neurophysiologists for diagnosis or treatment monitoring in neuropsychiatric disease. This chapter reviews systematically the TMS measures of motor cortical and corticospinal excitability from the perspective of pharmacophysiological characterization. For example, it is demonstrated that blockers of voltage-gated sodium channels specifically increase motor threshold but do not alter other TMS measures of excitability, whereas positive modulators at γ-butyric acid (GABA) type A receptors, such as benzodiazepines, enhance short-interval intracortical inhibition and depress motor evoked potential amplitude but have no effect on motor threshold.
Collapse
Affiliation(s)
- Ulf Ziemann
- Department of Neurology and Stroke, Hertie Institute for Clinical Brain Research, Eberhard-Karls University Tübingen, Tübingen, Germany.
| |
Collapse
|
27
|
Rupp T, Jubeau M, Wuyam B, Perrey S, Levy P, Millet GY, Verges S. Time-dependent effect of acute hypoxia on corticospinal excitability in healthy humans. J Neurophysiol 2012; 108:1270-7. [DOI: 10.1152/jn.01162.2011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Contradictory results regarding the effect of hypoxia on cortex excitability have been reported in healthy subjects, possibly depending on hypoxia exposure duration. We evaluated the effects of 1- and 3-h hypoxia on motor corticospinal excitability, intracortical inhibition, and cortical voluntary activation (VA) using transcranial magnetic stimulation (TMS). TMS to the quadriceps cortex area and femoral nerve electrical stimulations were performed in 14 healthy subjects. Motor-evoked potentials (MEPs at 50–100% maximal voluntary contraction; MVC), recruitment curves (MEPs at 30–100% maximal stimulator power output at 50% MVC), cortical silent periods (CSP), and VA were measured in normoxia and after 1 ( n = 12) or 3 ( n = 10) h of hypoxia (FiO2 = 0.12). One-hour hypoxia did not modify any parameters of corticospinal excitability but reduced slightly VA, probably due to the repetition of contractions 1 h apart (96 ± 4% vs. 94 ± 4%; P = 0.03). Conversely, 3-h hypoxia significantly increased 1) MEPs of the quadriceps muscles at all force levels (+26 ± 14%, +24 ± 12%, and +27 ± 17% at 50, 75, and 100% MVC, respectively; P = 0.01) and stimulator power outputs (e.g., +21 ± 14% at 70% maximal power), and 2) CSP at all force levels (+20 ± 18%, +18 ± 19%, and +14 ± 22% at 50, 75, and 100% MVC, respectively; P = 0.02) and stimulator power outputs (e.g., +9 ± 8% at 70% maximal power), but did not modify VA (98 ± 1% vs. 97 ± 3%; P = 0.42). These data demonstrate a time-dependent hypoxia-induced increase in motor corticospinal excitability and intracortical inhibition, without changes in VA. The impact of these cortical changes on physical or psychomotor performances needs to be elucidated to better understand the cerebral effects of hypoxemia.
Collapse
Affiliation(s)
- T. Rupp
- HP2 Laboratory, Joseph Fourier University & CHU Grenoble, Grenoble, France
- U1042, INSERM, Grenoble, France
| | - M. Jubeau
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, Saint-Etienne, France
- Laboratoire “Motricité, Interactions, Performance,” University of Nantes, Nantes, France; and
| | - B. Wuyam
- HP2 Laboratory, Joseph Fourier University & CHU Grenoble, Grenoble, France
- U1042, INSERM, Grenoble, France
| | - S. Perrey
- Movement To Health (M2H) Laboratory, Euromov, Montpellier-1 University, Montpellier, France
| | - P. Levy
- HP2 Laboratory, Joseph Fourier University & CHU Grenoble, Grenoble, France
- U1042, INSERM, Grenoble, France
| | - G. Y. Millet
- HP2 Laboratory, Joseph Fourier University & CHU Grenoble, Grenoble, France
- U1042, INSERM, Grenoble, France
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, Saint-Etienne, France
| | - S. Verges
- HP2 Laboratory, Joseph Fourier University & CHU Grenoble, Grenoble, France
- U1042, INSERM, Grenoble, France
| |
Collapse
|
28
|
Todd G, Rogasch NC, Türker KS. Transcranial magnetic stimulation and peristimulus frequencygram. Clin Neurophysiol 2012; 123:1002-9. [DOI: 10.1016/j.clinph.2011.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 09/22/2011] [Accepted: 09/26/2011] [Indexed: 11/25/2022]
|
29
|
Groppa S, Oliviero A, Eisen A, Quartarone A, Cohen LG, Mall V, Kaelin-Lang A, Mima T, Rossi S, Thickbroom GW, Rossini PM, Ziemann U, Valls-Solé J, Siebner HR. A practical guide to diagnostic transcranial magnetic stimulation: report of an IFCN committee. Clin Neurophysiol 2012; 123:858-82. [PMID: 22349304 DOI: 10.1016/j.clinph.2012.01.010] [Citation(s) in RCA: 804] [Impact Index Per Article: 67.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 01/16/2012] [Accepted: 01/22/2012] [Indexed: 11/29/2022]
Abstract
Transcranial magnetic stimulation (TMS) is an established neurophysiological tool to examine the integrity of the fast-conducting corticomotor pathways in a wide range of diseases associated with motor dysfunction. This includes but is not limited to patients with multiple sclerosis, amyotrophic lateral sclerosis, stroke, movement disorders, disorders affecting the spinal cord, facial and other cranial nerves. These guidelines cover practical aspects of TMS in a clinical setting. We first discuss the technical and physiological aspects of TMS that are relevant for the diagnostic use of TMS. We then lay out the general principles that apply to a standardized clinical examination of the fast-conducting corticomotor pathways with single-pulse TMS. This is followed by a detailed description of how to examine corticomotor conduction to the hand, leg, trunk and facial muscles in patients. Additional sections cover safety issues, the triple stimulation technique, and neuropediatric aspects of TMS.
Collapse
Affiliation(s)
- S Groppa
- Department of Neurology, Christian Albrechts University, Kiel, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Gjini K, Ziemann U, Napier TC, Boutros N. Dysbalance of cortical inhibition and excitation in abstinent cocaine-dependent patients. J Psychiatr Res 2012; 46:248-55. [PMID: 22036187 PMCID: PMC3264814 DOI: 10.1016/j.jpsychires.2011.10.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 10/10/2011] [Accepted: 10/13/2011] [Indexed: 01/11/2023]
Abstract
The effects of chronic cocaine dependence on cortical inhibitory/excitatory processes are not well characterized. Employing transcranial magnetic stimulation measures of motor cortical excitability, we have previously reported an elevation of motor threshold (MT) suggesting reduced excitability and an increased long-interval intracortical facilitation (LICF) suggesting increased excitability. In the current study, we used an expanded battery of TMS cortical excitability measures to further examine motor cortex excitability in a larger sample of well-characterized and closely monitored for drug use, abstinent cocaine-dependent subjects (N = 52) and healthy controls (N = 42). Furthermore, coil-to-cortex distance was assessed in a subsample of both groups. We verified that long-interval intracortical facilitation (LICF), possibly representing glutamatergic cortical neurotransmission, was significantly increased in cocaine-dependent patients. Significantly longer cortical silent periods (CSP) and elevated MT were also observed while there was no significant abnormality in long-interval intracortical inhibition (LICI). Increased LICF and CSP duration suggest increased cortical excitability and increased inhibition, respectively, of different neurotransmitter systems in cocaine-dependent patients. Increased MT might reflect an adaptation to those effects of cocaine abuse that enhance cortical excitability. Overall, the data point to the complex nature of chronic cocaine dependence on the balance of cortical inhibitory/excitatory mechanisms.
Collapse
Affiliation(s)
- Klevest Gjini
- Wayne State University, School of Medicine, Department of Psychiatry and Behavioral Neurosciences, 2751 E. Jefferson, Detroit, MI 48207, USA.
| | | | | | | |
Collapse
|
31
|
Filipović SR, Rothwell JC, Bhatia K. Slow (1 Hz) repetitive transcranial magnetic stimulation (rTMS) induces a sustained change in cortical excitability in patients with Parkinson's disease. Clin Neurophysiol 2010; 121:1129-37. [PMID: 20350836 DOI: 10.1016/j.clinph.2010.01.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 01/19/2010] [Accepted: 01/27/2010] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Low-frequency (< or =1 Hz) rTMS (LF-rTMS) can reduce excitability in the underlying cortex and/or promote inhibition. In patients with Parkinson's disease (PD) several TMS elicited features of motor corticospinal physiology suggest presence of impaired inhibitory mechanisms. These include shortened silent period (SP) and slightly steeper input-output (I-O) curve of motor evoked potential (MEP) size than in normal controls. However, studies of LF-rTMS effects on inhibitory mechanisms in PD are scarce. In this companion paper to the clinical paper describing effects of four consecutive days of LF-rTMS on dyskinesia in PD (Filipović et al., 2009), we evaluate the delayed (24h) effects of the LF-rTMS treatment on physiological measures of excitability of the motor cortex in the same patients. There are very few studies of physiological follow up of daily rTMS treatments. METHODS Nine patients with PD in Hoehn and Yahr stages 2 or 3 and prominent medication-induced dyskinesia were studied. This was a placebo-controlled, crossover study, with two treatment arms, "real" rTMS and "sham" rTMS (placebo). In each of the treatment arms, rTMS (1800 pulses; 1 Hz rate; intensity of the real stimuli just-below the active motor threshold) was delivered over the motor cortex for four consecutive days. Motor cortex excitability was evaluated at the beginning of the study and the next day following each of the four-day rTMS series (real and sham) with patients first in the practically defined "off" state, following 12h withdrawal of medication, and subsequently in a typical "on" state following usual morning medication dose. RESULTS The SP was significantly longer following real rTMS in comparison to both baseline and sham rTMS. The effect was independent from the effects of dopaminergic treatment. There was no difference in MEP size, rest and active motor threshold. The I-O curve, recorded from the relaxed muscle, showed a trend towards diminished slope in comparison to baseline, but the difference was not significant. There was no consistent correlation between prolongation of SP and concomitant reduction in dyskinesia following real rTMS. CONCLUSIONS Low-frequency rTMS delivered over several consecutive days changes the excitability of motor cortex by increasing the excitability of inhibitory circuits. The effects persist for at least a day after rTMS. SIGNIFICANCE The results confirm the existence of a residual after-effect of consecutive daily applications of rTMS that might be relevant to the clinical effect that was observed in this group of patients and could be further exploited for potential therapeutic uses.
Collapse
Affiliation(s)
- Sasa R Filipović
- Burden Neurological Institute, Bristol, UK; Institute for Medical Research, Beograd, Serbia.
| | | | | |
Collapse
|
32
|
Bonnard M, Spieser L, Meziane HB, de Graaf JB, Pailhous J. Prior intention can locally tune inhibitory processes in the primary motor cortex: direct evidence from combined TMS-EEG. Eur J Neurosci 2009; 30:913-23. [PMID: 19712104 DOI: 10.1111/j.1460-9568.2009.06864.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- M Bonnard
- Mediterranean Institute of Cognitive Neuroscience, UMR 6193, CNRS-University of Aix-Marseille, Marseille Cedex 20, France
| | | | | | | | | |
Collapse
|
33
|
Filipović SR, Papathanasiou I, Whurr R, Rothwell JC, Jahanshahi M. Differential effect of linguistic and non-linguistic pen-holding tasks on motor cortex excitability. Exp Brain Res 2008; 191:237-46. [PMID: 18712373 DOI: 10.1007/s00221-008-1517-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2007] [Accepted: 07/21/2008] [Indexed: 10/21/2022]
Abstract
Writing and drawing are unique human activities. They are complex high-precision actions, which involve not only the motor system but also various cognitive systems, such as attention, short-term memory, action control, and language. In relation to motor control, the study of writing and drawing is of great interest as they provide insight in the interaction between motor control processes and the concurrent non-motor processes. Although sharing similar motor and mechanical demands, writing and drawing involve different levels of linguistic/semantic load and thus may be associated with different modulation of motor cortical excitability. Here, we have used transcranial magnetic stimulation to study separately activation of excitatory and inhibitory mechanisms of the motor cortex during performance of writing and drawing acts as well as during simple pen-squeezing task. While cortical excitatory mechanisms appeared to be saturated by the pure motor demands of the tasks, and thus not amenable to modulation by the tasks' linguistic load, variation in cortical inhibitory activity was the main vehicle for differential modulation of motor cortical excitability by linguistic demands of the tasks. The results of this study highlight the importance of cortical inhibitory mechanisms in the physiology of higher cognitive activities. They also provide further evidence that the task specific modulation of the excitability of the motor cortex goes beyond motor complexity of the task and is also dependant on associated cognitive components.
Collapse
Affiliation(s)
- Sasa R Filipović
- Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
| | | | | | | | | |
Collapse
|
34
|
Paulus W, Classen J, Cohen LG, Large CH, Di Lazzaro V, Nitsche M, Pascual-Leone A, Rosenow F, Rothwell JC, Ziemann U. State of the art: Pharmacologic effects on cortical excitability measures tested by transcranial magnetic stimulation. Brain Stimul 2008; 1:151-63. [PMID: 20633382 DOI: 10.1016/j.brs.2008.06.002] [Citation(s) in RCA: 309] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/02/2008] [Accepted: 06/06/2008] [Indexed: 11/19/2022] Open
Abstract
The combination of brain stimulation techniques like transcranial magnetic stimulation (TMS) with CNS active drugs in humans now offers a unique opportunity to explore the physiologic effects of these substances in vivo in the human brain. Motor threshold, motor evoked potential size, motor evoked potential intensity curves, cortical silent period, short-interval intracortical inhibition, intracortical facilitation, short-interval intracortical facilitation, long-interval intracortical inhibition and short latency afferent inhibition represent the repertoire for investigating drug effects on motor cortical excitability by TMS. Here we present an updated overview on the pharmacophysiologic mechanisms with special emphasis on methodologic pitfalls and possible future developments or requirements.
Collapse
Affiliation(s)
- Walter Paulus
- Department of Clinical Neurophysiology, University of Göttingen, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Kimura T, Haggard P, Gomi H. Transcranial magnetic stimulation over sensorimotor cortex disrupts anticipatory reflex gain modulation for skilled action. J Neurosci 2006; 26:9272-81. [PMID: 16957083 PMCID: PMC6674505 DOI: 10.1523/jneurosci.3886-05.2006] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Skilled interactions with new environments require flexible changes to the transformation from somatosensory signals to motor outputs. Transcortical reflex gains are known to be modulated according to task and environmental dynamics, but the mechanism of this modulation remains unclear. We examined reflex organization in the sensorimotor cortex. Subjects performed point-to-point arm movements into predictable force fields. When a small perturbation was applied just before the arm encountered the force field, reflex responses in the shoulder muscles changed according to the upcoming force field direction, indicating anticipatory reflex gain modulation. However, when a transcranial magnetic stimulation (TMS) was applied before the reflex response to such perturbations so that the silent period caused by TMS overlapped the reflex processing period, this modulation was abolished, while the reflex itself remained. Loss of reflex gain modulation could not be explained by reduced reflex amplitudes nor by peripheral effects of TMS on the muscles themselves. Instead, we suggest that TMS disrupted interneuronal networks in the sensorimotor cortex, which contribute to reflex gain modulation rather than reflex generation. We suggest that these networks normally provide the adaptability of rapid sensorimotor reflex responses by regulating reflex gains according to the current dynamical environment.
Collapse
Affiliation(s)
- Toshitaka Kimura
- NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, Kanagawa 243-0198, Japan.
| | | | | |
Collapse
|
36
|
Tazoe T, Endoh T, Nakajima T, Sakamoto M, Komiyama T. Disinhibition of upper limb motor area by voluntary contraction of the lower limb muscle. Exp Brain Res 2006; 177:419-30. [PMID: 16977446 DOI: 10.1007/s00221-006-0686-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Accepted: 08/21/2006] [Indexed: 10/24/2022]
Abstract
It is well known that monosynaptic spinal reflexes and motor evoked potentials following transcranial magnetic stimulation (TMS) are reinforced during phasic and intensive voluntary contraction in the remote segment (remote effect). However, the remote effect on the cortical silent period (CSP) is less known. The purpose of the present study is to determine to what extent the CSP in the intrinsic hand muscle following TMS is modified by voluntary ankle dorsiflexion and to elucidate the origin of the modulation of CSP by the remote effect. CSP was recorded in the right first dorsal interosseous while subjects performed phasic dorsiflexion in the ipsilateral side under self-paced and reaction-time conditions. Modulation of the peripherally-induced silent period (PSP) induced by electrical stimulation of the ulnar nerve was also investigated under the same conditions. In addition, modulation of the CSP was investigated during ischemic nerve block of the lower limb and during application of vibration to the tibialis anterior tendon. The duration of CSP was significantly shortened by phasic dorsiflexion, and the extent of shortening was proportional to dorsiflexion force. Shortening of the CSP duration was also observed during tonic dorsiflexion. In contrast, the PSP duration following ulnar nerve stimulation was not altered during phasic dorsiflexion. Furthermore, the remote effect on the CSP duration was seen during ischemic nerve block of the lower limb and the pre-movement period in the reaction-time paradigm, but shortening of the CSP was not observed during tendon vibration. These findings suggest that phasic muscle contraction in the remote segment results in a decrease in intracortical inhibitory pathways to the corticospinal tract innervating the muscle involved in reflex testing and that the remote effect on the CSP is predominantly cortical in origin.
Collapse
Affiliation(s)
- Toshiki Tazoe
- Division of Health and Sport Education, United Graduate School of Education, Tokyo Gakugei University, 1-33 Yayoi-cho, Inage-ku, Chiba City 263-8522, Japan.
| | | | | | | | | |
Collapse
|
37
|
Fecteau S, Lassonde M, Théoret H. Intrahemispheric dysfunction in primary motor cortex without corpus callosum: a transcranial magnetic stimulation study. BMC Neurol 2006; 6:21. [PMID: 16790050 PMCID: PMC1513595 DOI: 10.1186/1471-2377-6-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2005] [Accepted: 06/21/2006] [Indexed: 11/11/2022] Open
Abstract
Background The two human cerebral hemispheres are continuously interacting, through excitatory and inhibitory influences and one critical structure subserving this interhemispheric balance is the corpus callosum. Interhemispheric neurophysiological abnormalities and intrahemispheric behavioral impairments have been reported in individuals lacking the corpus callosum. The aim of this study was to examine intrahemispheric neurophysiological function in primary motor cortex devoid of callosal projections. Methods Intracortical excitatory and inhibitory systems were tested in three individuals with complete agenesis of the corpus callosum and sixteen healthy individuals. These systems were assessed using transcranial magnetic stimulation (TMS) protocols: motor threshold at rest, paired-pulse curve, and cortical silent period. Results TMS revealed no difference between the patient and control groups on the motor threshold measure, as well as intracortical facilitation and intracortical inhibition systems as tested by paired stimulation. However, intrahemispheric inhibitory function was found to be abnormal in participants without callosal projections, as the cortical silent period duration was significantly increased in the patient group. Conclusion These data suggest that in addition to previously reported impaired interhemispheric function, patients lacking the entire corpus callosum also display abnormal intrahemispheric excitability of the primary motor cortex.
Collapse
Affiliation(s)
- Shirley Fecteau
- Centre de Recherche en Neuropsychologie et Cognition, Département de Psychologie, Université de Montréal and Hôpital Sainte-Justine, Montreal, Canada
- Center for Non-Invasive Brain Stimulation, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, USA
- Center for Non-Invasive Brain Stimulation, Harvard MedicalSchool, Beth Israel Deaconess Medical Center, 300 Brookline, Boston, MA 02215, USA
| | - Maryse Lassonde
- Centre de Recherche en Neuropsychologie et Cognition, Département de Psychologie, Université de Montréal and Hôpital Sainte-Justine, Montreal, Canada
- Département de Psychologie, Université de Montréal, CP 6128, Succ. Centre-Ville, Montréal, QC, H3C 3J7, Canada
| | - Hugo Théoret
- Centre de Recherche en Neuropsychologie et Cognition, Département de Psychologie, Université de Montréal and Hôpital Sainte-Justine, Montreal, Canada
- Département de Psychologie, Université de Montréal, CP 6128, Succ. Centre-Ville, Montréal, QC, H3C 3J7, Canada
| |
Collapse
|
38
|
Søgaard K, Gandevia SC, Todd G, Petersen NT, Taylor JL. The effect of sustained low-intensity contractions on supraspinal fatigue in human elbow flexor muscles. J Physiol 2006; 573:511-23. [PMID: 16556656 PMCID: PMC1779725 DOI: 10.1113/jphysiol.2005.103598] [Citation(s) in RCA: 213] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Subjects quickly fatigue when they perform maximal voluntary contractions (MVCs). Much of the loss of force is from processes within muscle (peripheral fatigue) but some occurs because voluntary activation of the muscle declines (central fatigue). The role of central fatigue during submaximal contractions is not clear. This study investigated whether central fatigue developed during prolonged low-force voluntary contractions. Subjects (n=9) held isometric elbow flexions of 15% MVC for 43 min. Voluntary activation was measured during brief MVCs every 3 min. During each MVC, transcranial magnetic stimulation (TMS) was followed by stimulation of either brachial plexus or the motor nerve of biceps brachii. After nerve stimulation, a resting twitch was also evoked before subjects resumed the 15% MVC. Perceived effort, elbow flexion torque and surface EMG from biceps, brachioradialis and triceps were recorded. TMS was also given during the sustained 15% MVC. During the sustained contraction, perceived effort rose from approximately 2 to approximately 8 (out of 10) while ongoing biceps EMG increased from 6.9+/-2.1% to 20.0+/-7.8% of initial maximum. Torque in the brief MVCs and the resting twitch fell to 58.6+/-14.5 and 58.2+/-13.2% of control values, respectively. EMG in the MVCs also fell to 62.2+/-15.3% of initial maximum, and twitches evoked by nerve stimulation and TMS grew progressively. Voluntary activation calculated from these twitches fell from approximately 98% to 71.9+/-38.9 and 76.9+/-18.3%, respectively. The silent period following TMS lengthened both in the brief MVCs (by approximately 40 ms) and in the sustained target contraction (by approximately 18 ms). After the end of the sustained contraction, the silent period recovered immediately, voluntary activation and voluntary EMG recovered over several minutes while MVC torque only returned to approximately 85% baseline. The resting twitch showed no recovery. Thus, as well as fatigue in the muscle, the prolonged low-force contraction produced progressive central fatigue, and some of this impairment of the subjects' ability to drive the muscle maximally was due to suboptimal output from the motor cortex. Although caused by a low-force contraction, both the peripheral and central fatigue impaired the production of maximal voluntary force. While central fatigue can only be demonstrated during MVCs, it may have contributed to the disproportionate increase in perceived effort reported during the prolonged low-force contraction.
Collapse
Affiliation(s)
- Karen Søgaard
- National Institute of Occupational Health, Lersø Parkalle 102, 2100 Copenhagen Ø, Denmark.
| | | | | | | | | |
Collapse
|
39
|
Kimiskidis VK, Papagiannopoulos S, Kazis DA, Sotirakoglou K, Vasiliadis G, Zara F, Kazis A, Mills KR. Lorazepam-induced effects on silent period and corticomotor excitability. Exp Brain Res 2006; 173:603-11. [PMID: 16525803 DOI: 10.1007/s00221-006-0402-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Accepted: 02/04/2006] [Indexed: 10/24/2022]
Abstract
TMS studies on the CNS effects of benzodiazepines have provided contradictory results. The objective of this study is to describe the effects of lorazepam on silent period (SP) and corticomotor excitability. Twelve healthy male subjects (median age 35 years) were studied at baseline, following i.v. lorazepam administration and after reversal of the benzodiazepine effects with i.v. flumazenil. Lorazepam was given at a low-dose in one subject (0.0225 mg/kg bolus + 2 microg/kg/h infusion) and at a high-dose (0.045 mg/kg bolus + 2.6 microg/kg/h infusion) in the rest. Threshold (Thr) was measured at 1% steps. SPs were investigated with two complementary methods. First, SPs were elicited using a wide range of stimulus intensities (SIs) (from 5 to 100% maximum SI at 5% increments). At each SI, four SPs were obtained and the average value of SP duration was used to construct a stimulus/response (S/R) curve of SI versus SP .The resulting S/R curves were then fitted to a Boltzman function, the best-fit values of which were statistically compared for each experimental condition (i.e., baseline vs. lorazepam vs. flumazenil). Second, a large number of SPs (n=100) was elicited during each of the three experimental conditions using blocks of four stimuli with an intensity alternating between MT and 200% MT. This method was employed so as to reveal the dynamic, time-varying effects of lorazepam and flumazenil on SP duration at two stimulus intensity (SI) levels. MEP recruitment curves were constructed at rest and during activation and fitted to a Boltzman function the best-fit values of which were statistically compared for each experimental condition. Lorazepam at a low dose did not affect Thr, SP, or the active MEP recruitment curves. The high dose also had no effect on Thr and the active MEPs whereas the resting MEP recruitment curves were depressed post-lorazepam at the higher range of stimulus intensities. With regard to SP, the Max value of the S/R curve decreased from 251+/-4.6 ms at baseline to 215.2+/-3.1 ms post-lorazepam (P<0.01). V50 also decreased significantly (from 47.92+/-0.9% to 43.73+/-0.81%, P<0.01) whereas there was no significant change regarding slope and SP Thr. The statistical analysis of the SP S/R curves as well as the study of SPs at two SI levels revealed that lorazepam reduced SP duration when high intensity stimuli were used (>60%). In contrast, at low SIs a small increase in SP duration was noted post-drug. Enhancement of GABAergic inhibition by lorazepam results in a reduction of SP duration when high SIs is used. At the lower range of SIs, a small but statistically significant increase in SP duration is observed. The kinetic behavior of this phenomenon as well as the possible underlying mechanisms are discussed.
Collapse
Affiliation(s)
- V K Kimiskidis
- Department of Neurology III, G.Papanikolaou Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece.
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Bajbouj M, Lisanby SH, Lang UE, Danker-Hopfe H, Heuser I, Neu P. Evidence for impaired cortical inhibition in patients with unipolar major depression. Biol Psychiatry 2006; 59:395-400. [PMID: 16197927 DOI: 10.1016/j.biopsych.2005.07.036] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2004] [Revised: 04/22/2005] [Accepted: 07/25/2005] [Indexed: 11/22/2022]
Abstract
BACKGROUND Several lines of evidence suggest that central cortical inhibitory mechanisms, especially associated with gamma-aminobutyric acid (GABA) neurotransmission, may play a role in the pathophysiology of major depression. Transcranial magnetic stimulation is a useful tool for investigating central cortical inhibitory mechanisms associated with GABAergic neurotransmission in psychiatric and neurological disorders. METHODS By means of transcranial magnetic stimulation, different parameters of cortical excitability, including motor threshold, the cortical silent period, and intracortical inhibition/facilitation, were investigated in 20 medication-free depressed patients and 20 age- and gender-matched healthy volunteers. RESULTS Silent period and intracortical inhibition were reduced in depressed patients, consistent with a reduced GABAergic tone. Moreover, patients showed a significant hemispheric asymmetry in motor threshold. CONCLUSIONS This study provides evidence of reduced GABAergic tone and motor threshold asymmetry in patients with major depression.
Collapse
Affiliation(s)
- Malek Bajbouj
- Department of Psychiatry, Charité University Medicine Berlin, Berlin, Germany.
| | | | | | | | | | | |
Collapse
|
41
|
Bajbouj M, Brakemeier EL, Schubert F, Lang UE, Neu P, Schindowski C, Danker-Hopfe H. Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex and cortical excitability in patients with major depressive disorder. Exp Neurol 2005; 196:332-8. [PMID: 16194530 DOI: 10.1016/j.expneurol.2005.08.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 07/21/2005] [Accepted: 08/15/2005] [Indexed: 10/25/2022]
Abstract
Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex is a relatively non-invasive technique with putative therapeutic effects in major depression. However, the exact neurophysiological basis of these effects needs further clarification. Therefore, we studied the impact of ten daily sessions of left, dorsolateral prefrontal rTMS on motor cortical excitability, as revealed by transcranial magnetic stimulation-elicited motor-evoked potentials in 30 patients. As compared to the non-responders, responders (33%) showed changes in parameters pointing towards a reduced cortical excitability. These results suggest that repetitive transcranial magnetic stimulation of the dorsolateral, prefrontal cortex may have inhibitory effects on motor cortical neuronal excitability in patients with major depressive disorder. Furthermore, measurement of motor cortical excitability may be a useful tool for investigating and monitoring inhibitory brain effects of antidepressant stimulation techniques like rTMS.
Collapse
Affiliation(s)
- Malek Bajbouj
- Department of Psychiatry, Charité-University Medicine Berlin, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany.
| | | | | | | | | | | | | |
Collapse
|
42
|
Di Lazzaro V, Oliviero A, Saturno E, Dileone M, Pilato F, Nardone R, Ranieri F, Musumeci G, Fiorilla T, Tonali P. Effects of lorazepam on short latency afferent inhibition and short latency intracortical inhibition in humans. J Physiol 2005; 564:661-8. [PMID: 15718269 PMCID: PMC1464438 DOI: 10.1113/jphysiol.2004.061747] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Experimental studies have demonstrated that the GABAergic system modulates acetylcholine release and, through GABA(A) receptors, tonically inhibits cholinergic activity. Little is known about the effects of GABA on the cholinergic activity in the human central nervous system. In vivo evaluation of some cholinergic circuits of the human brain has recently been introduced using a transcranial magnetic stimulation (TMS) protocol based on coupling peripheral nerve stimulation with TMS of the motor cortex. Peripheral nerve inputs have an inhibitory effect on motor cortex excitability at short intervals (short latency afferent inhibition, SAI). We investigated whether GABA(A) activity enhancement by lorazepam modifies SAI. We also evaluated the effects produced by lorazepam on a different TMS protocol of cortical inhibition, the short interval intracortical inhibition (SICI), which is believed to be directly related to GABA(A) activity. In 10 healthy volunteers, the effects of lorazepam were compared with those produced by quetiapine, a psychotropic drug with sedative effects with no appreciable affinity at cholinergic muscarinic and benzodiazepine receptors, and with those of a placebo using a randomized double-blind study design. Administration of lorazepam produced a significant increase in SICI (F(3,9) = 3.19, P = 0.039). In contrast to SICI, SAI was significantly reduced by lorazepam (F(3,9) = 9.39, P = 0.0002). Our findings demonstrate that GABA(A) activity enhancement determines a suppression of SAI and an increase of SICI.
Collapse
Affiliation(s)
- V Di Lazzaro
- Istituto di Neurologia, Università Cattolica, L.go A. Gemelli 8, 00168 Rome, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Kimiskidis VK, Papagiannopoulos S, Sotirakoglou K, Kazis DA, Kazis A, Mills KR. Silent period to transcranial magnetic stimulation: construction and properties of stimulus-response curves in healthy volunteers. Exp Brain Res 2005; 163:21-31. [PMID: 15690156 DOI: 10.1007/s00221-004-2134-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 10/07/2004] [Indexed: 11/28/2022]
Abstract
Silent period (SP) is widely used in transcranial magnetic stimulation studies. Methodologically, SP is usually elicited at stimulus intensities corresponding to a certain percentage of corticomotor threshold. Because this approach might lead to factitious SP changes, the present study was designed to develop, in a stepwise manner, a method for investigating SP independently of corticomotor threshold. First, stimulus-response (S-R) curves of SP against stimulus intensity (SI) were constructed and quantitatively described in healthy volunteers. Second, various methodological issues such as the optimum model for describing the relationship between SP duration and SI and the importance of the type of stimulating coil were addressed. Finally, the proposed method and a commonly used method (eliciting SPs at 130% MT SI) were directly compared for a group of epileptic patients for whom administration of oxcarbazepine resulted in significant corticomotor threshold elevation. Twenty-one subjects (eleven females, median age, 38 years) were studied. SPs were obtained with a figure-of-eight coil using a standardized procedure (recording, FDI). Pilot experiments indicated that at least four trials were required, at each intensity level, to estimate the mean SP duration within 10% of the true mean. Therefore, SPs were determined from the average of four trials with 5% increments from 5 to 100% maximum SI. In a second set of experiments, SPs were obtained for fifteen subjects using a circular coil. In a third set of experiments, eight epileptic patients were studied before and after administration of oxcarbazepine (mean dose 1553 mg, range 900-1800 mg). The S-R curves were fitted to a Boltzman function and to first-order to fourth-order polynomial and sigmoid functions. The Boltzman function described the data accurately (R2=0.947-0.990). In addition, direct comparison of the six models with an F-test proved the superiority of the first. The best-fit parameters of the reference curve, i.e. the maximum and minimum values, the slope, and V50 (the SI at which SP duration is halfway between Min and Max) were 230.8+/-3.31 ms (x+/-SEM), -11.51+/-3.31 ms, 11.56+/-0.65%, and 49.82+/-0.65%, respectively. When the curves obtained with the circular coil were compared with those obtained with the figure-of-eight coil, there were differences between V50 (51.69+/-0.72 vs 47.95+/-0.82, P<0.001) and SP threshold (31.15 vs 24.77, P<0.01) whereas the other best-fit values did not differ significantly. Oxcarbazepine increased corticomotor threshold from 45.3+/-5.8% at baseline to 59.4+/-10.4% (P<0.001). According to the commonly used method, the drug significantly prolonged SP (from 117.6+/-42.4 ms to 143.5+/-46.5 ms, P<0.001) and, consequently, enhanced brain inhibition. In contrast, study of the SP curves led to the conclusion that oxcarbazepine does not affect the Max value and slope but significantly increases V50 and SP threshold (from 54.5+/-4.9% to 59.9+/-7.2% and from 29.1+/-6.4% to 34.6+/-6.8%, respectively, P<0.01). These findings imply that oxcarbazepine does not enhance brain inhibitory mechanisms. Thus, in situations characterized by significant changes in corticomotor threshold the proposed method provides results clearly different from a commonly used approach. It is concluded that S-R curves obtained with a figure-of-eight coil in 5% increments and fitted to a Boltzman function provide an accurate, comprehensive, and clinically applicable method for exploring SP.
Collapse
Affiliation(s)
- V K Kimiskidis
- Department of Neurology III, G. Papanikolaou Hospital, Aristotle University of Thessaloniki, 57010 Thessaloniki, Greece.
| | | | | | | | | | | |
Collapse
|
44
|
Abstract
The application of a single dose of a CNS active drug with a well-defined mode of action on a neurotransmitter or neuromodulator system may be used for testing pharmaco-physiological properties of transcranial magnetic stimulation (TMS) measures of cortical excitability. Conversely, a physiologically well-defined single TMS measure of cortical excitability may be used as a biological marker of acute drug effects at the systems level of the cerebral cortex. An array of defined TMS measures may be used to study the pattern of effects of a drug with unknown or multiple modes of action. Acute drug effects may be rather different from chronic drug effects. These differences can also be studied by TMS measures. Finally, TMS or repetitive TMS by themselves may induce changes in endogenous neurotransmitters or neuromodulators. All these possible interactions are the focus of this in-depth review on TMS and drugs.
Collapse
Affiliation(s)
- Ulf Ziemann
- Motor Cortex Laboratory, Clinic of Neurology, Johann Wolfgang Goethe University Frankfurt, Schleusenweg 2-16, D-60528 Frankfurt am Main, Germany.
| |
Collapse
|
45
|
Cortical threshold and excitability measurements. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s1567-4231(04)04017-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
46
|
Andersen B, Westlund B, Krarup C. Failure of activation of spinal motoneurones after muscle fatigue in healthy subjects studied by transcranial magnetic stimulation. J Physiol 2003; 551:345-56. [PMID: 12824449 PMCID: PMC2343163 DOI: 10.1113/jphysiol.2003.043562] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
During a sustained maximal effort a progressive decline in the ability to drive motoneurones (MNs) develops. We used the recently developed triple stimulation technique (TST) to study corticospinal conduction after fatiguing exercise in healthy subjects. This method employs a collision technique to estimate the proportion of motor units activated by a transcranial magnetic stimulus. Following a sustained contraction of the abductor digiti minimi muscle at 50 % maximal force maintained to exhaustion there was an immediate reduction of the TST response from > 95 % to about 60 %. This effect recovered to control levels within 1 min and implies that a decreased number of spinal MNs were excited. Additional TST experiments after maximal and submaximal efforts showed that the decrease in size of the TST response was related to duration and strength of exercise. Motor evoked potentials (MEPs) after conventional transcranial magnetic stimulation (TMS) and responses to peripheral nerve stimulation were recorded following the same fatigue protocol. The size of both the MEPs and the peripheral responses increased after the contraction and were in direct contrast to the decrease in size of the TST response. This points to increased probability of repetitive spinal MN activation during fatigue even if some MNs in the pool failed to discharge. Silent period duration following cortical stimulation lengthened by an average of 55 ms after the contraction and recovered within a time course similar to that of the TST response depression. Overall, the results suggest that the outflow from the motor cortex could become insufficient to drive all spinal MNs to discharge when the muscle is fatigued and that complex interactions between failure of activation and compensatory mechanisms to maintain motor unit activation occur during sustained voluntary activity. When inability to maintain force occurs during submaximal effort, failure of activation of motor units is predominant.
Collapse
Affiliation(s)
- Birgit Andersen
- Department of Clinical Neurophysiology 3063, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
| | | | | |
Collapse
|
47
|
Todd G, Petersen NT, Taylor JL, Gandevia SC. The effect of a contralateral contraction on maximal voluntary activation and central fatigue in elbow flexor muscles. Exp Brain Res 2003; 150:308-13. [PMID: 12677313 DOI: 10.1007/s00221-003-1379-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2002] [Accepted: 12/09/2002] [Indexed: 11/26/2022]
Abstract
A long-duration, submaximal contraction of a hand muscle increases central fatigue during a subsequent contraction in the other hand. However, this 'cross-over' of central fatigue between limbs is small and the location within the central nervous system at which this effect occurs is unknown. We investigated this 'cross-over' by measurement of the force and EMG responses to transcranial magnetic stimulation of the motor cortex (TMS). To produce central fatigue, we used sustained maximal voluntary contractions (MVCs). In the first study, subjects (n=10) performed four 1-min sustained MVCs of the elbow flexors, alternating between the left and right arms (two MVCs per arm). The sustained MVCs were performed consecutively with no rest periods. In the second study, the same subjects made two sustained 1-min MVCs with the same arm with a 1-min rest between efforts. During each sustained MVC, a series of TMS and brachial plexus stimuli were delivered. Surface EMG was recorded from biceps brachii and brachioradialis muscles bilaterally. Voluntary activation was estimated during each MVC using measurement of the force increments to TMS. On average during each sustained MVC, voluntary activation declined by 7-12% (absolute change, P<0.001) and voluntary force declined by 35-45% MVC (P<0.001), whereas the cortical motor-evoked potential increased (P<0.001) and the subsequent silent period lengthened (P<0.001). The average voluntary activation and voluntary force were similar during two sustained MVCs performed by the same arm, when separated by 1 min of rest. However, when the 1-min rest interval was replaced with a sustained contraction performed by the other arm, the average voluntary activation was 2.9% worse in the second contraction (absolute change, P<0.05), while it did not alter voluntary force production or the EMG responses to TMS. Therefore, in maximal exercise of 4 min duration, the 'cross-over' of central fatigue between limbs is small in the elbow flexors and has a minor functional effect. Our data suggest that voluntary drive from the motor cortex is slightly less able to drive the muscle maximally after a fatiguing voluntary contraction on the contralateral side.
Collapse
Affiliation(s)
- Gabrielle Todd
- Prince of Wales Medical Research Institute and the University of New South Wales, 2031 Sydney, Australia
| | | | | | | |
Collapse
|
48
|
Tinazzi M, Farina S, Tamburin S, Facchini S, Fiaschi A, Restivo D, Berardelli A. Task-dependent modulation of excitatory and inhibitory functions within the human primary motor cortex. Exp Brain Res 2003; 150:222-9. [PMID: 12677319 DOI: 10.1007/s00221-003-1448-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2002] [Accepted: 02/22/2003] [Indexed: 11/30/2022]
Abstract
We evaluated motor evoked potentials (MEPs) and duration of the cortical silent period (CSP) from the right first dorsal interosseous (FDI) muscle to transcranial magnetic stimulation (TMS) of the left motor cortex in ten healthy subjects performing different manual tasks. They abducted the index finger alone, pressed a strain gauge with the thumb and index finger in a pincer grip, and squeezed a 4-cm brass cylinder with all digits in a power grip. The level of FDI EMG activity across tasks was kept constant by providing subjects with acoustic-visual feedback of their muscle activity. The TMS elicited larger amplitude FDI MEPs during pincer and power grip than during the index finger abduction task, and larger amplitude MEPs during pincer gripping than during power gripping. The CSP was shorter during pincer and power grip than during the index finger abduction task and shorter during power gripping than during pincer gripping. These results suggest excitatory and inhibitory task-dependent changes in the motor cortex. Complex manual tasks (pincer and power gripping) elicit greater motor cortical excitation than a simple task (index finger abduction) presumably because they activate multiple synergistic muscles thus facilitating corticomotoneurons. The finger abduction task probably yielded greater motor cortical inhibition than the pincer and power tasks because muscles uninvolved in the task activated the cortical inhibitory circuit. Increased cortical excitatory and inhibitory functions during precision tasks (pincer gripping) probably explain why MEPs have larger amplitudes and CSPs have longer durations during pincer gripping than during power gripping.
Collapse
Affiliation(s)
- Michele Tinazzi
- Dipartimento di Scienze Neurologiche e della Visione, Sezione di Neurologia Riabilitativa, Università di Verona, Policlinico G. B. Rossi, P.le A. L. Scuro, 37134, Verona, Italy.
| | | | | | | | | | | | | |
Collapse
|
49
|
Chapter 8 Transcranial magnetic stimulation. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1567-4231(09)70156-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
50
|
Abbruzzese G, Trompetto C. Clinical and research methods for evaluating cortical excitability. J Clin Neurophysiol 2002; 19:307-21. [PMID: 12436087 DOI: 10.1097/00004691-200208000-00005] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The evaluation of motor cortical output after transcranial magnetic stimulation (TMS) is a means of investigating how the motor cortex reacts to external stimuli (i.e., a method to assess the excitability of the motor cortex). The recording of the descending volleys at the surface of the spinal cord provides a direct measure of the motor cortical output. However, this approach is highly invasive and can be used only during particular conditions. On the other hand, electromyographic recordings of the motor phenomena induced by TMS provide a completely painless, noninvasive, indirect measure of the cortical output, with these phenomena obviously reflecting the excitability of the spinal motoneurons as well as that of the muscle itself. The authors review how the electromyographic activity induced by TMS can provide valuable information about motor cortical excitability for use in clinical practice and research.
Collapse
Affiliation(s)
- Giovanni Abbruzzese
- Laboratory of Clinical Neurophysiology, Department of Neurological Sciences & Vision, University of Genoa, Italy.
| | | |
Collapse
|