1
|
Koponen LM, Martinez M, Wood E, Murphy DLK, Goetz SM, Appelbaum LG, Peterchev AV. Transcranial magnetic stimulation input-output curve slope differences suggest variation in recruitment across muscle representations in primary motor cortex. Front Hum Neurosci 2024; 18:1310320. [PMID: 38384332 PMCID: PMC10879434 DOI: 10.3389/fnhum.2024.1310320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 01/29/2024] [Indexed: 02/23/2024] Open
Abstract
Measurement of the input-output (IO) curves of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) can be used to assess corticospinal excitability and motor recruitment. While IO curves have been used to study disease and pharmacology, few studies have compared the IO curves across the body. This study sought to characterize IO curve parameters across the dominant and non-dominant sides of upper and lower limbs in healthy participants. Laterality preferences were assessed in eight healthy participants and IO curves were measured bilaterally for the first dorsal interosseous (FDI), biceps brachii (BB), and tibialis anterior (TA) muscles. Results show that FDI has lower motor threshold than BB which is, in turn, lower than TA. In addition, both BB and TA have markedly shallower logarithmic IO curve slopes from small to large MEP responses than FDI. After normalizing these slopes by their midpoints to account for differences in motor thresholds, which could result from geometric factors such as the target depth, large differences in logarithmic slopes remain present between all three muscles. The differences in slopes between the muscles could not be explained by differences in normalized IO curve spreads, which relate to the extent of the cortical representation and were comparable across the muscles. The IO curve differences therefore suggest muscle-dependent variations in TMS-evoked recruitment across the primary motor cortex, which should be considered when utilizing TMS-evoked MEPs to study disease states and treatment effects.
Collapse
Affiliation(s)
- Lari M. Koponen
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Birmingham, UK
| | - Miles Martinez
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States
- Center for Cognitive Neuroscience, Duke University, Durham, NC, United States
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States
| | - Eleanor Wood
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States
| | - David L. K. Murphy
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States
| | - Stefan M. Goetz
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States
- Department of Neurosurgery, Duke University, Durham, NC, United States
| | - Lawrence G. Appelbaum
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Angel V. Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States
- Department of Neurosurgery, Duke University, Durham, NC, United States
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| |
Collapse
|
2
|
Woodhead A, North JS, Hill J, Murphy CP, Kidgell DJ, Tallent J. Corticospinal and spinal adaptations following lower limb motor skill training: a meta-analysis with best evidence synthesis. Exp Brain Res 2023; 241:807-824. [PMID: 36740653 DOI: 10.1007/s00221-023-06563-3] [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: 05/24/2022] [Accepted: 01/21/2023] [Indexed: 02/07/2023]
Abstract
Motor skill training alters the human nervous system; however, lower limb motor tasks have been less researched compared to upper limb tasks. This meta-analysis with best evidence synthesis aimed to determine the cortical and subcortical responses that occur following lower limb motor skill training, and whether these responses are accompanied by improvements in motor performance. Following a literature search that adhered to the PRISMA guidelines, data were extracted and analysed from six studies (n = 172) for the meta-analysis, and 11 studies (n = 257) were assessed for the best evidence synthesis. Pooled data indicated that lower limb motor skill training increased motor performance, with a standardised mean difference (SMD) of 1.09 being observed. However, lower limb motor skill training had no effect on corticospinal excitability (CSE), Hoffmann's reflex (H-reflex) or muscle compound action potential (MMAX) amplitude. The best evidence synthesis found strong evidence for improved motor performance and reduced short-interval cortical inhibition (SICI) following lower limb motor skill training, with conflicting evidence towards the modulation of CSE. Taken together, this review highlights the need for further investigation on how motor skill training performed with the lower limb musculature can modulate corticospinal responses. This will also help us to better understand whether these neuronal measures are underpinning mechanisms that support an improvement in motor performance.
Collapse
Affiliation(s)
- Alex Woodhead
- Faculty of Sport, Allied Health and Performance Science, St. Mary's University, Middlesex, Twickenham, TW1 4SX, UK.
| | - Jamie S North
- Faculty of Sport, Allied Health and Performance Science, St. Mary's University, Middlesex, Twickenham, TW1 4SX, UK
| | - Jessica Hill
- Faculty of Sport, Allied Health and Performance Science, St. Mary's University, Middlesex, Twickenham, TW1 4SX, UK
| | - Colm P Murphy
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Dawson J Kidgell
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, VIC, 3199, Australia
| | - Jamie Tallent
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, VIC, 3199, Australia.,School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Wivenhoe Park, Colchester, UK
| |
Collapse
|
3
|
Assessing the feasibility of mapping the tibialis anterior muscle with navigated transcranial magnetic stimulation in neuro-oncologic patients. Sci Rep 2022; 12:18719. [PMID: 36333400 PMCID: PMC9636142 DOI: 10.1038/s41598-022-23444-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Mapping the lower extremity with navigated transcranial magnetic stimulation (nTMS) still remains challenging for the investigator. Clinical factors influencing leg mapping with nTMS have not been fully investigated yet. The aim of the study was to identify factors which influence the possibility of eliciting motor evoked potentials (MEPs) from the tibialis anterior muscle (TA). Patient records, imaging, nTMS examinations and tractography were retrospectively evaluated. 48 nTMS examinations were performed in 46 brain tumor patients. Reproducible MEPs were recorded in 20 patients (41.67%). Younger age (p = 0.044) and absence of perifocal edema (p = 0.035, Cramer's V = 0.34, OR = 0.22, 95% CI = 0.06-0.81) facilitated mapping the TA muscle. Leg motor deficit (p = 0.49, Cramer's V = 0.12, OR = 0.53, 95%CI = 0.12-2.36), tumor entity (p = 0.36, Cramer's V = 0.22), tumor location (p = 0.52, Cramer's V = 0.26) and stimulation intensity (p = 0.158) were no significant factors. The distance between the tumor and the pyramidal tract was higher (p = 0.005) in patients with successful mapping of the TA. The possibility to stimulate the leg motor area was associated with no postoperative aggravation of motor deficits in general (p = 0.005, Cramer's V = 0.45, OR = 0.63, 95%CI = 0.46-0.85) but could not serve as a specific predictor of postoperative lower extremity function. In conclusion, successful mapping of the TA muscle for neurosurgical planning is influenced by young patient age, absence of edema and greater distance to the CST, whereas tumor entity and stimulation intensity were non-significant.
Collapse
|
4
|
Gomez-Feria J, Fernandez-Corazza M, Martin-Rodriguez JF, Mir P. TMS intensity and focality correlation with coil orientation at three non-motor regions. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4ef9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 01/26/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. The aim of this study is to define the best coil orientations for transcranial magnetic stimulation (TMS) for three clinically relevant brain areas: pre-supplementary motor area (pre-SMA), inferior frontal gyrus (IFG), and posterior parietal cortex (PPC), by means of simulations in 12 realistic head models of the electric field (E-field). Methods. We computed the E-field generated by TMS in our three volumes of interest (VOI) that were delineated based on published atlases. We then analysed the maximum intensity and spatial focality for the normal and absolute components of the E-field considering different percentile thresholds. Lastly, we correlated these results with the different anatomical properties of our VOIs. Results. Overall, the spatial focality of the E-field for the three VOIs varied depending on the orientation of the coil. Further analysis showed that differences in individual brain anatomy were related to the amount of focality achieved. In general, a larger percentage of sulcus resulted in better spatial focality. Additionally, a higher normal E-field intensity was achieved when the coil axis was placed perpendicular to the predominant orientations of the gyri of each VOI. A positive correlation between spatial focality and E-field intensity was found for PPC and IFG but not for pre-SMA. Conclusions. For a rough approximation, better coil orientations can be based on the individual’s specific brain morphology at the VOI. Moreover, TMS computational models should be employed to obtain better coil orientations in non-motor regions of interest. Significance. Finding better coil orientations in non-motor regions is a challenge in TMS and seeks to reduce interindividual variability. Our individualized TMS simulation pipeline leads to fewer inter-individual variability in the focality, likely enhancing the efficacy of the stimulation and reducing the risk of stimulating adjacent, non-targeted areas.
Collapse
|
5
|
Mrachacz-Kersting N, Stevenson AJT, Ziemann U. Short-interval intracortical inhibition and facilitation targeting upper and lower limb muscles. Sci Rep 2021; 11:21993. [PMID: 34754010 PMCID: PMC8578654 DOI: 10.1038/s41598-021-01348-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/27/2021] [Indexed: 11/30/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) can be used to study excitability of corticospinal neurons in human motor cortex. It is currently not fully elucidated if corticospinal neurons in the hand vs. leg representation show the same or different regulation of their excitability by GABAAergic and glutamatergic interneuronal circuitry. Using a paired-pulse TMS protocol we tested short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF) in 18 healthy participants. Motor evoked potentials were evoked in one hand (abductor digiti minimi) and one leg muscle (tibialis anterior), with systematic variation of the intensities of the first (S1) and second (S2) pulse between 60 and 140% resting motor threshold (RMT) in 10% steps, at two interstimulus intervals of 1.5 and 2.1 ms. For the hand and leg motor representations and for both interstimulus intervals, SICI occurred if the intensities of S1 < RMT and S2 > RMT, while SICF predominated if S1 = S2 ≤ RMT, or S1 > RMT and S2 < RMT. Findings confirm and extend previous evidence that the regulation of excitability of corticospinal neurons of the hand versus leg representation in human primary cortex through GABAAergic and glutamatergic interneuronal circuits is highly similar, and that corticospinal neurons of both representations are activated by TMS transsynaptically in largely identical ways.
Collapse
Affiliation(s)
| | | | - Ulf Ziemann
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| |
Collapse
|
6
|
Hand BJ, Opie GM, Sidhu SK, Semmler JG. Motor cortex plasticity and visuomotor skill learning in upper and lower limbs of endurance-trained cyclists. Eur J Appl Physiol 2021; 122:169-184. [DOI: 10.1007/s00421-021-04825-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/30/2021] [Indexed: 11/29/2022]
|
7
|
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
|