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Pascarella A, Manzo L, Ferlazzo E. Modern neurophysiological techniques indexing normal or abnormal brain aging. Seizure 2024:S1059-1311(24)00194-8. [PMID: 38972778 DOI: 10.1016/j.seizure.2024.07.001] [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: 04/09/2024] [Accepted: 07/01/2024] [Indexed: 07/09/2024] Open
Abstract
Brain aging is associated with a decline in cognitive performance, motor function and sensory perception, even in the absence of neurodegeneration. The underlying pathophysiological mechanisms remain incompletely understood, though alterations in neurogenesis, neuronal senescence and synaptic plasticity are implicated. Recent years have seen advancements in neurophysiological techniques such as electroencephalography (EEG), magnetoencephalography (MEG), event-related potentials (ERP) and transcranial magnetic stimulation (TMS), offering insights into physiological and pathological brain aging. These methods provide real-time information on brain activity, connectivity and network dynamics. Integration of Artificial Intelligence (AI) techniques promise as a tool enhancing the diagnosis and prognosis of age-related cognitive decline. Our review highlights recent advances in these electrophysiological techniques (focusing on EEG, ERP, TMS and TMS-EEG methodologies) and their application in physiological and pathological brain aging. Physiological aging is characterized by changes in EEG spectral power and connectivity, ERP and TMS parameters, indicating alterations in neural activity and network function. Pathological aging, such as in Alzheimer's disease, is associated with further disruptions in EEG rhythms, ERP components and TMS measures, reflecting underlying neurodegenerative processes. Machine learning approaches show promise in classifying cognitive impairment and predicting disease progression. Standardization of neurophysiological methods and integration with other modalities are crucial for a comprehensive understanding of brain aging and neurodegenerative disorders. Advanced network analysis techniques and AI methods hold potential for enhancing diagnostic accuracy and deepening insights into age-related brain changes.
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Affiliation(s)
- Angelo Pascarella
- Department of Medical and Surgical Sciences, Magna Græcia University of Catanzaro, Italy; Regional Epilepsy Centre, Great Metropolitan "Bianchi-Melacrino-Morelli Hospital", Reggio Calabria, Italy.
| | - Lucia Manzo
- Regional Epilepsy Centre, Great Metropolitan "Bianchi-Melacrino-Morelli Hospital", Reggio Calabria, Italy
| | - Edoardo Ferlazzo
- Department of Medical and Surgical Sciences, Magna Græcia University of Catanzaro, Italy; Regional Epilepsy Centre, Great Metropolitan "Bianchi-Melacrino-Morelli Hospital", Reggio Calabria, Italy
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Frey VN, Langthaler PB, Renz N, Zimmermann G, Höhn C, Schwenker K, Thomschewski A, Kunz AB, Höller Y, Nardone R, Trinka E. Influence of sports on cortical excitability in patients with spinal cord injury: a TMS study. FRONTIERS IN MEDICAL TECHNOLOGY 2024; 6:1297552. [PMID: 38812566 PMCID: PMC11133579 DOI: 10.3389/fmedt.2024.1297552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 04/19/2024] [Indexed: 05/31/2024] Open
Abstract
Background Patients with spinal cord injury (SCI) show abnormal cortical excitability that might be caused by deafferentation. We hypothesize a reduced short-interval intracortical inhibition preceding movement in patients with SCI compared with healthy participants. In addition, we expect that neuroplasticity induced by different types of sports can modulate intracortical inhibition during movement preparation in patients with SCI. Methods We used a reaction test and paired-pulse transcranial magnetic stimulation to record cortical excitability, assessed by measuring amplitudes of motor-evoked potentials in preparation of movement. The participants were grouped as patients with SCI practicing wheelchair dancing (n = 7), other sports (n = 6), no sports (n = 9), and healthy controls (n = 24). Results There were neither significant differences between healthy participants and the patients nor between the different patient groups. A non-significant trend (p = .238), showed that patients engaged in sports have a stronger increase in cortical excitability compared with patients of the non-sportive group, while the patients in the other sports group expressed the highest increase in cortical excitability. Conclusion The small sample sizes limit the statistical power of the study, but the trending effect warrants further investigation of different sports on the neuroplasticity in patients with SCI. It is not clear how neuroplastic changes impact the sensorimotor output of the affected extremities in a patient. This needs to be followed up in further studies with a greater sample size.
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Affiliation(s)
- Vanessa N. Frey
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Patrick B. Langthaler
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
- Department of Mathematics, Paris Lodron University, Salzburg, Austria
| | - Nora Renz
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Georg Zimmermann
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- IDA Lab Salzburg, Team Biostatistics and Big Medical Data, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Christopher Höhn
- Laboratory for Sleep, Cognition and Consciousness Research, Department of Psychology, Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
| | - Kerstin Schwenker
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
- Karl Landsteiner Institute for Neurorehabilitation and Space Neurology Salzburg, Salzburg, Austria
| | - Aljoscha Thomschewski
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Alexander B. Kunz
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Karl Landsteiner Institute for Neurorehabilitation and Space Neurology Salzburg, Salzburg, Austria
| | - Yvonne Höller
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Faculty of Psychology, University of Akureyri, Akureyri, Iceland
| | - Raffaele Nardone
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
- Karl Landsteiner Institute for Neurorehabilitation and Space Neurology Salzburg, Salzburg, Austria
- Department of Neurology, Tappeiner Hospital, Meran, Italy
| | - Eugen Trinka
- Department of Neurology, Neurointensive Care and Neurorehabilitation, Member of the European Reference Network EpiCARE, Christian Doppler University Hospital, Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
- Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
- Karl Landsteiner Institute for Neurorehabilitation and Space Neurology Salzburg, Salzburg, Austria
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Haggie L, Besier T, McMorland A. Circuits in the motor cortex explain oscillatory responses to transcranial magnetic stimulation. Netw Neurosci 2024; 8:96-118. [PMID: 38562291 PMCID: PMC10861165 DOI: 10.1162/netn_a_00341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/11/2023] [Indexed: 04/04/2024] Open
Abstract
Transcranial magnetic stimulation (TMS) is a popular method used to investigate brain function. Stimulation over the motor cortex evokes muscle contractions known as motor evoked potentials (MEPs) and also high-frequency volleys of electrical activity measured in the cervical spinal cord. The physiological mechanisms of these experimentally derived responses remain unclear, but it is thought that the connections between circuits of excitatory and inhibitory neurons play a vital role. Using a spiking neural network model of the motor cortex, we explained the generation of waves of activity, so called 'I-waves', following cortical stimulation. The model reproduces a number of experimentally known responses including direction of TMS, increased inhibition, and changes in strength. Using populations of thousands of neurons in a model of cortical circuitry we showed that the cortex generated transient oscillatory responses without any tuning, and that neuron parameters such as refractory period and delays influenced the pattern and timing of those oscillations. By comparing our network with simpler, previously proposed circuits, we explored the contributions of specific connections and found that recurrent inhibitory connections are vital in producing later waves that significantly impact the production of motor evoked potentials in downstream muscles (Thickbroom, 2011). This model builds on previous work to increase our understanding of how complex circuitry of the cortex is involved in the generation of I-waves.
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Affiliation(s)
- Lysea Haggie
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Thor Besier
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Angus McMorland
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand
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Wischnewski M, Tran H, Zhao Z, Shirinpour S, Haigh ZJ, Rotteveel J, Perera ND, Alekseichuk I, Zimmermann J, Opitz A. Induced neural phase precession through exogenous electric fields. Nat Commun 2024; 15:1687. [PMID: 38402188 PMCID: PMC10894208 DOI: 10.1038/s41467-024-45898-5] [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: 05/05/2023] [Accepted: 02/06/2024] [Indexed: 02/26/2024] Open
Abstract
The gradual shifting of preferred neural spiking relative to local field potentials (LFPs), known as phase precession, plays a prominent role in neural coding. Correlations between the phase precession and behavior have been observed throughout various brain regions. As such, phase precession is suggested to be a global neural mechanism that promotes local neuroplasticity. However, causal evidence and neuroplastic mechanisms of phase precession are lacking so far. Here we show a causal link between LFP dynamics and phase precession. In three experiments, we modulated LFPs in humans, a non-human primate, and computational models using alternating current stimulation. We show that continuous stimulation of motor cortex oscillations in humans lead to a gradual phase shift of maximal corticospinal excitability by ~90°. Further, exogenous alternating current stimulation induced phase precession in a subset of entrained neurons (~30%) in the non-human primate. Multiscale modeling of realistic neural circuits suggests that alternating current stimulation-induced phase precession is driven by NMDA-mediated synaptic plasticity. Altogether, the three experiments provide mechanistic and causal evidence for phase precession as a global neocortical process. Alternating current-induced phase precession and consequently synaptic plasticity is crucial for the development of novel therapeutic neuromodulation methods.
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Affiliation(s)
- Miles Wischnewski
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA.
| | - Harry Tran
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Zhihe Zhao
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Sina Shirinpour
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Zachary J Haigh
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Jonna Rotteveel
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Nipun D Perera
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Ivan Alekseichuk
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Jan Zimmermann
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Alexander Opitz
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA.
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Wischnewski M, Tran H, Zhao Z, Shirinpour S, Haigh Z, Rotteveel J, Perera N, Alekseichuk I, Zimmermann J, Opitz A. Induced neural phase precession through exogeneous electric fields. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535073. [PMID: 37034780 PMCID: PMC10081336 DOI: 10.1101/2023.03.31.535073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
The gradual shifting of preferred neural spiking relative to local field potentials (LFPs), known as phase precession, plays a prominent role in neural coding. Correlations between the phase precession and behavior have been observed throughout various brain regions. As such, phase precession is suggested to be a global neural mechanism that promotes local neuroplasticity. However, causal evidence and neuroplastic mechanisms of phase precession are lacking so far. Here we show a causal link between LFP dynamics and phase precession. In three experiments, we modulated LFPs in humans, a non-human primate, and computational models using alternating current stimulation. We show that continuous stimulation of motor cortex oscillations in humans lead to a gradual phase shift of maximal corticospinal excitability by ~90°. Further, exogenous alternating current stimulation induced phase precession in a subset of entrained neurons (~30%) in the non-human primate. Multiscale modeling of realistic neural circuits suggests that alternating current stimulation-induced phase precession is driven by NMDA-mediated synaptic plasticity. Altogether, the three experiments provide mechanistic and causal evidence for phase precession as a global neocortical process. Alternating current-induced phase precession and consequently synaptic plasticity is crucial for the development of novel therapeutic neuromodulation methods.
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Affiliation(s)
- M. Wischnewski
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - H. Tran
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Z. Zhao
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - S. Shirinpour
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Z.J. Haigh
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - J. Rotteveel
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - N.D. Perera
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - I. Alekseichuk
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - J. Zimmermann
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, USA
| | - A. Opitz
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
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Germann M, Baker SN. Testing a Novel Wearable Device for Motor Recovery of the Elbow Extensor Triceps Brachii in Chronic Spinal Cord Injury. eNeuro 2023; 10:ENEURO.0077-23.2023. [PMID: 37460228 PMCID: PMC10399611 DOI: 10.1523/eneuro.0077-23.2023] [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: 02/22/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 07/29/2023] Open
Abstract
After corticospinal tract damage, reticulospinal connections to motoneurons strengthen preferentially to flexor muscles. This could contribute to the disproportionately poor recovery of extensors often seen after spinal cord injury (SCI) and stroke. In this study, we paired electrical stimulation over the triceps muscle with auditory clicks, using a wearable device to deliver stimuli over a prolonged period of time. Healthy human volunteers wore the stimulation device for ∼6 h and a variety of electrophysiological assessments were used to measure changes in triceps motor output. In contrast to previous results in the biceps muscle, paired stimulation: (1) did not increase the StartReact effect; (2) did not decrease the suppression of responses to transcranial magnetic brain stimulation (TMS) following a loud sound; (3) did not enhance muscle responses elicited by a TMS coil oriented to induce anterior-posterior current. In a second study, chronic cervical SCI survivors wore the stimulation device for ∼4 h every day for four weeks; this was compared with a four-week period without wearing the device. Functional and electrophysiological assessments were repeated at week 0, week 4, and week 8. No significant changes were observed in electrophysiological assessments after paired stimulation. Functional measurements such as maximal force and variability and speed of trajectories made during a planar reaching task also remained unchanged. Our results suggest that the triceps muscle shows less potential for plasticity than biceps; pairing clicks with muscle stimulation does not seem beneficial in enhancing triceps recovery after SCI.
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Affiliation(s)
- Maria Germann
- Institute of Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Stuart N Baker
- Institute of Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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Covariation of the amplitude and latency of motor evoked potentials elicited by transcranial magnetic stimulation in a resting hand muscle. Exp Brain Res 2023; 241:927-936. [PMID: 36811686 PMCID: PMC9985579 DOI: 10.1007/s00221-023-06575-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 02/13/2023] [Indexed: 02/24/2023]
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique used to study human neurophysiology. A single TMS pulse delivered to the primary motor cortex can elicit a motor evoked potential (MEP) in a target muscle. MEP amplitude is a measure of corticospinal excitability and MEP latency is a measure of the time taken for intracortical processing, corticofugal conduction, spinal processing, and neuromuscular transmission. Although MEP amplitude is known to vary across trials with constant stimulus intensity, little is known about MEP latency variation. To investigate MEP amplitude and latency variation at the individual level, we scored single-pulse MEP amplitude and latency in a resting hand muscle from two datasets. MEP latency varied from trial to trial in individual participants with a median range of 3.9 ms. Shorter MEP latencies were associated with larger MEP amplitudes for most individuals (median r = - 0.47), showing that latency and amplitude are jointly determined by the excitability of the corticospinal system when TMS is delivered. TMS delivered during heightened excitability could discharge a greater number of cortico-cortical and corticospinal cells, increasing the amplitude and, by recurrent activation of corticospinal cells, the number of descending indirect waves. An increase in the amplitude and number of indirect waves would progressively recruit larger spinal motor neurons with large-diameter fast-conducting fibers, which would shorten MEP onset latency and increase MEP amplitude. In addition to MEP amplitude variability, understanding MEP latency variability is important given that these parameters are used to help characterize pathophysiology of movement disorders.
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Kesselheim J, Takemi M, Christiansen L, Karabanov AN, Siebner HR. Multipulse transcranial magnetic stimulation of human motor cortex produces short-latency corticomotor facilitation via two distinct mechanisms. J Neurophysiol 2023; 129:410-420. [PMID: 36629338 DOI: 10.1152/jn.00263.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Single-pulse transcranial magnetic stimulation (TMS) of the precentral hand representation (M1HAND) can elicit indirect waves in the corticospinal tract at a periodicity of ∼660 Hz, called I-waves. These descending volleys are produced by transsynaptic excitation of fast-conducting corticospinal axons in M1HAND. Paired-pulse TMS can induce short-interval intracortical facilitation (SICF) of motor evoked potentials (MEPs) at interpulse intervals that match I-wave periodicity. This study examined whether short-latency corticospinal facilitation engages additional mechanisms independently of I-wave periodicity. In 19 volunteers, one to four biphasic TMS pulses were applied to left M1HAND with interpulse intervals adjusted to the first peak or trough of the individual SICF curve at different intensities to probe the intensity-response relationship. Multipulse TMSHAND at individual peak latency facilitated MEP amplitudes and reduced resting motor threshold (RMT) compared with single pulses. Multipulse TMSHAND at individual trough latency also produced a consistent facilitation of MEPs and a reduction of RMT. Short-latency facilitation at trough latency was less pronounced, but the relative difference in facilitation decreased with increasing stimulus intensity. Increasing the pulse number had only a modest effect. Two mechanisms underlie short-latency facilitation caused by biphasic multipulse TMSHAND. One intracortical mechanism is related to I-wave periodicity and engages fast-conducting direct projections to spinal motoneurons. A second corticospinal mechanism does not rely on I-wave rhythmicity and may be mediated by slower-conducting indirect pyramidal tract projections from M1HAND to spinal interneurons. The latter mechanism deserves more attention in studies of the corticomotor system and its link to manual motor control using the MEP.NEW & NOTEWORTHY TMS pairs evoke SICF at interpulse intervals (IPIs) that match I-wave periodicity. Biphasic bursts with IPIs at the latency of the first peak facilitate MEPs and reduce corticomotor threshold. Bursts at the latency of the first trough facilitate MEPs and reduce corticomotor threshold to a lesser extent. TMS bursts facilitate corticomotor excitability via two mechanisms: SICF-dependently via fast-conducting direct projections from M1HAND to spinal motoneurons and SICF-independently, probably through slower-conducting indirect pyramidal tract projections.
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Affiliation(s)
- Janine Kesselheim
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
| | - Mitsuaki Takemi
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark.,Division of Physical and Health Education, Graduate School of Education, The University of Tokyo, Bunkyo City, Tokyo, Japan
| | - Lasse Christiansen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark
| | - Anke Ninija Karabanov
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark.,Section for Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark.,Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen NV, Denmark.,Institute for Clinical Medicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen N, Denmark
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Jannati A, Oberman LM, Rotenberg A, Pascual-Leone A. Assessing the mechanisms of brain plasticity by transcranial magnetic stimulation. Neuropsychopharmacology 2023; 48:191-208. [PMID: 36198876 PMCID: PMC9700722 DOI: 10.1038/s41386-022-01453-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/10/2022]
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive technique for focal brain stimulation based on electromagnetic induction where a fluctuating magnetic field induces a small intracranial electric current in the brain. For more than 35 years, TMS has shown promise in the diagnosis and treatment of neurological and psychiatric disorders in adults. In this review, we provide a brief introduction to the TMS technique with a focus on repetitive TMS (rTMS) protocols, particularly theta-burst stimulation (TBS), and relevant rTMS-derived metrics of brain plasticity. We then discuss the TMS-EEG technique, the use of neuronavigation in TMS, the neural substrate of TBS measures of plasticity, the inter- and intraindividual variability of those measures, effects of age and genetic factors on TBS aftereffects, and then summarize alterations of TMS-TBS measures of plasticity in major neurological and psychiatric disorders including autism spectrum disorder, schizophrenia, depression, traumatic brain injury, Alzheimer's disease, and diabetes. Finally, we discuss the translational studies of TMS-TBS measures of plasticity and their therapeutic implications.
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Affiliation(s)
- Ali Jannati
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Lindsay M Oberman
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Alexander Rotenberg
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Alvaro Pascual-Leone
- Department of Neurology, Harvard Medical School, Boston, MA, USA.
- Hinda and Arthur Marcus Institute for Aging Research and Deanna and Sidney Wolk Center for Memory Health, Hebrew SeniorLife, Boston, MA, USA.
- Guttmann Brain Health Institute, Institut Guttmann, Barcelona, Spain.
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10
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Ni Z, Pajevic S, Chen L, Leodori G, Vial F, Avram AV, Zhang Y, McGurrin P, Cohen LG, Basser PJ, Hallett M. Identifying transcranial magnetic stimulation induced EEG signatures of different neuronal elements in primary motor cortex. Clin Neurophysiol 2022; 141:42-52. [PMID: 35841868 PMCID: PMC9398981 DOI: 10.1016/j.clinph.2022.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/17/2022] [Accepted: 06/21/2022] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the neuronal elements involved in the activation of corticospinal neurons in the primary motor cortex (M1). METHODS We studied 10 healthy subjects. Cortical evoked potentials with different components induced by monophasic transcranial magnetic stimulation (TMS) in anterior-posterior and posterior-anterior currents recorded with electroencephalography (EEG) were analyzed. RESULTS EEG signatures with P25 and N45 components recorded at the C3 electrode with posterior-anterior current were larger than those with anterior-posterior current, while the signatures with P180 and N280 components recorded at the FC1 electrode with anterior-posterior current were larger than those with posterior-anterior current. The source localization analysis revealed that the cortical evoked potential with anterior-posterior current distributed both in the M1 and premotor cortex while that with posterior-anterior current only located in the M1. CONCLUSIONS We conclude that the activation of corticospinal pyramidal neurons in the M1 is affected by various neuronal elements including the local intracortical circuits in the M1 and inputs from premotor cortex with different sensitivities to TMS in opposite current directions. SIGNIFICANCE Our finding helped answer a longstanding question about how the corticospinal pathway from the M1 is functionally organized and activated.
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Affiliation(s)
- Zhen Ni
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA
| | - Sinisa Pajevic
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA
| | - Li Chen
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA
| | | | - Felipe Vial
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA; Facultad de Medicina Clinica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Alexandru V Avram
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA; National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, USA
| | - Yong Zhang
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA
| | - Patrick McGurrin
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA
| | - Leonardo G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA
| | - Peter J Basser
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA.
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11
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Ferreri F, Francesca M, Fabrizio V, Manzo N, Maria C, Elda J, Rossini PM. EEG, ERPs, and EROs in patients with neurodegenerative dementing disorders: A window into the cortical neurophysiology of cognition and behavior. Int J Psychophysiol 2022; 181:85-94. [PMID: 36055410 DOI: 10.1016/j.ijpsycho.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/20/2022] [Accepted: 08/18/2022] [Indexed: 10/31/2022]
Abstract
In the human brain, physiological aging is characterized by progressive neuronal loss, leading to disruption of synapses and to a degree of failure in neurotransmission and information flow. However, there is increasing evidence to support the notion that the aged brain has a remarkable level of resilience (i.s. ability to reorganize itself), with the aim of preserving its physiological activity. It is therefore of paramount interest to develop objective markers able to characterize the biological processes underlying brain aging in the intact human, and to distinguish them from brain degeneration associated to age-related neurological progressive diseases like Alzheimer's disease. EEG, alone and combined with transcranial magnetic stimulation (TMS-EEG), is particularly suited to this aim, due to the functional nature of the information provided, and thanks to the ease with which it can be integrated in ecological scenarios including behavioral tasks. In this review, we aimed to provide the reader with updated information about the role of modern methods of EEG and TMS-EEG analysis in the investigation of physiological brain aging and Alzheimer's disease. In particular, we focused on data about cortical connectivity obtained by using readouts such graph theory network brain organization and architecture, and transcranial evoked potentials (TEPs) during TMS-EEG. Overall, findings in the literature support an important potential contribution of such neurophysiological techniques to the understanding of the mechanisms underlying normal brain aging and the early (prodromal/pre-symptomatic) stages of dementia.
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Affiliation(s)
- Florinda Ferreri
- Unit of Neurology, Unit of Clinical Neurophysiology and Study Center of Neurodegeneration (CESNE), Department of Neuroscience, University of Padua, Padua, Italy; Department of Clinical Neurophysiology, Kuopio University Hospital, University of Eastern Finland, Kuopio, Finland
| | - Miraglia Francesca
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, Rome, Italy; Department of Theoretical and Applied Sciences, eCampus University, Novedrate, Como, Italy.
| | - Vecchio Fabrizio
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, Rome, Italy; Department of Theoretical and Applied Sciences, eCampus University, Novedrate, Como, Italy
| | - Nicoletta Manzo
- IRCCS San Camillo Hospital, Via Alberoni 70, 30126 Lido di Venezia, Venice, Italy
| | - Cotelli Maria
- Neuropsychology Unit, IRCCS Istituto Centro San Giovanni di DioFatebenefratelli, Brescia, Italy
| | - Judica Elda
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milano, Italy
| | - Paolo Maria Rossini
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Roma, Rome, Italy
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12
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Siebner HR, Funke K, Aberra AS, Antal A, Bestmann S, Chen R, Classen J, Davare M, Di Lazzaro V, Fox PT, Hallett M, Karabanov AN, Kesselheim J, Beck MM, Koch G, Liebetanz D, Meunier S, Miniussi C, Paulus W, Peterchev AV, Popa T, Ridding MC, Thielscher A, Ziemann U, Rothwell JC, Ugawa Y. Transcranial magnetic stimulation of the brain: What is stimulated? - A consensus and critical position paper. Clin Neurophysiol 2022; 140:59-97. [PMID: 35738037 PMCID: PMC9753778 DOI: 10.1016/j.clinph.2022.04.022] [Citation(s) in RCA: 119] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 03/14/2022] [Accepted: 04/15/2022] [Indexed: 12/11/2022]
Abstract
Transcranial (electro)magnetic stimulation (TMS) is currently the method of choice to non-invasively induce neural activity in the human brain. A single transcranial stimulus induces a time-varying electric field in the brain that may evoke action potentials in cortical neurons. The spatial relationship between the locally induced electric field and the stimulated neurons determines axonal depolarization. The induced electric field is influenced by the conductive properties of the tissue compartments and is strongest in the superficial parts of the targeted cortical gyri and underlying white matter. TMS likely targets axons of both excitatory and inhibitory neurons. The propensity of individual axons to fire an action potential in response to TMS depends on their geometry, myelination and spatial relation to the imposed electric field and the physiological state of the neuron. The latter is determined by its transsynaptic dendritic and somatic inputs, intrinsic membrane potential and firing rate. Modeling work suggests that the primary target of TMS is axonal terminals in the crown top and lip regions of cortical gyri. The induced electric field may additionally excite bends of myelinated axons in the juxtacortical white matter below the gyral crown. Neuronal excitation spreads ortho- and antidromically along the stimulated axons and causes secondary excitation of connected neuronal populations within local intracortical microcircuits in the target area. Axonal and transsynaptic spread of excitation also occurs along cortico-cortical and cortico-subcortical connections, impacting on neuronal activity in the targeted network. Both local and remote neural excitation depend critically on the functional state of the stimulated target area and network. TMS also causes substantial direct co-stimulation of the peripheral nervous system. Peripheral co-excitation propagates centrally in auditory and somatosensory networks, but also produces brain responses in other networks subserving multisensory integration, orienting or arousal. The complexity of the response to TMS warrants cautious interpretation of its physiological and behavioural consequences, and a deeper understanding of the mechanistic underpinnings of TMS will be critical for advancing it as a scientific and therapeutic tool.
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Affiliation(s)
- Hartwig R Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark; Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Klaus Funke
- Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum, Bochum, Germany
| | - Aman S Aberra
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Sven Bestmann
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Robert Chen
- Krembil Brain Institute, University Health Network and Division of Neurology, University of Toronto, Toronto, Ontario, Canada
| | - Joseph Classen
- Department of Neurology, University of Leipzig, Leipzig, Germany
| | - Marco Davare
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, via Álvaro del Portillo 21, 00128 Rome, Italy
| | - Peter T Fox
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Anke N Karabanov
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Nutrition and Exercise, University of Copenhagen, Copenhagen, Denmark
| | - Janine Kesselheim
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Mikkel M Beck
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Giacomo Koch
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy; Non-invasive Brain Stimulation Unit, Laboratorio di NeurologiaClinica e Comportamentale, Fondazione Santa Lucia IRCCS, Rome, Italy
| | - David Liebetanz
- Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Sabine Meunier
- Sorbonne Université, Faculté de Médecine, INSERM U 1127, CNRS 4 UMR 7225, Institut du Cerveau, F-75013, Paris, France
| | - Carlo Miniussi
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy; Cognitive Neuroscience Section, IRCCS Centro San Giovanni di DioFatebenefratelli, Brescia, Italy
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Angel V Peterchev
- Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Psychiatry & Behavioral Sciences, School of Medicine, Duke University, Durham, NC, USA; Department of Electrical & Computer Engineering, Duke University, Durham, NC, USA; Department of Neurosurgery, School of Medicine, Duke University, Durham, NC, USA
| | - Traian Popa
- Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland; Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Michael C Ridding
- University of South Australia, IIMPACT in Health, Adelaide, Australia
| | - Axel Thielscher
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Ulf Ziemann
- Department of Neurology & Stroke, University Tübingen, Tübingen, Germany; Hertie Institute for Clinical Brain Research, University Tübingen, Tübingen, Germany
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Yoshikazu Ugawa
- Department of Neurology, Fukushima Medical University, Fukushima, Japan; Fukushima Global Medical Science Centre, Advanced Clinical Research Centre, Fukushima Medical University, Fukushima, Japan
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13
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Martinotti G, Pettorruso M, Montemitro C, Spagnolo PA, Acuti Martellucci C, Di Carlo F, Fanella F, di Giannantonio M. Repetitive transcranial magnetic stimulation in treatment-seeking subjects with cocaine use disorder: A randomized, double-blind, sham-controlled trial. Prog Neuropsychopharmacol Biol Psychiatry 2022; 116:110513. [PMID: 35074451 DOI: 10.1016/j.pnpbp.2022.110513] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/06/2022] [Accepted: 01/16/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND Cocaine use disorder (CUD) is a chronic and relapsing brain disorder with no approved treatments. Repetitive transcranial magnetic stimulation (rTMS) has shown promising results in open label and single-blind studies, reducing cocaine craving and consumption. Although, large randomized, double-blind, controlled trials are still missing. OBJECTIVE This multi-center, randomized, double-blind, sham-controlled study was designed to evaluate the safety and efficacy of multiple sessions of active rTMS compared to sham stimulation in patients with CUD. METHODS rTMS (15 Hz, 2 daily sessions for 5 days/week,for a total of 20 stimulation sessions) was delivered over the left DLPFC for two weeks of continuous treatment followed by 12 weeks of maintenance (1 day/week, twice a day), in a double-blind, randomized sham-controlled design. Our primary outcomes included self-reported cue-induced craving and cocaine consumption, as measured by percentage of negative urine tests. Our secondary outcomes included: 1) changes in depressive symptoms; 2) changes in cocaine withdrawal symptoms; and 3) changes in self-reported days of cocaine use. RESULTS Forty-two outpatients with CUD were enrolled in the active rTMS group and 38 patients in the sham group. We observed a significant decrease in self-reported cue-induced cocaine craving and consumption in both the active rTMS and sham, whereas no main effect of treatment was found. However, the active rTMS group showed greater changes in depressive symptoms. The improvement on depressive symptomatology was particularly marked among patients receiving a total number of rTMS sessions greater than 40 and those reporting more severe depressive symptoms at baseline. CONCLUSIONS A significant improvement of CUD symptoms during active rTMS treatment was observed. However, we did not observe significant differences in cocaine craving and consumption between treatment groups, highlighting the complexity of factors contributing to CUD maintenance. A significant improvement in depressive symptoms was observed in favour of the active group. Clinical trial registration details:clinicaltrials.govidentifierNCT03333460.
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Affiliation(s)
- Giovanni Martinotti
- Department of Neuroscience, Imaging and Clinical Sciences, "G. d'Annunzio" University, Chieti, Italy; Department of Pharmacy, Pharmacology and Postgraduate Medicine, University of Hertfordshire, Hatfield, UK; SRP Villa Maria Pia, Mental Health and Addiction Inpatient Unit, Rome, Italy.
| | - Mauro Pettorruso
- Department of Neuroscience, Imaging and Clinical Sciences, "G. d'Annunzio" University, Chieti, Italy
| | - Chiara Montemitro
- Department of Neuroscience, Imaging and Clinical Sciences, "G. d'Annunzio" University, Chieti, Italy; National Institute of Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
| | - Primavera Alessandra Spagnolo
- National Institute of Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States; National Institute on Neurological Disorders and Stroke, Intramural Research Program, National Institutes of Health, Bethesda, MD, United States
| | | | - Francesco Di Carlo
- Department of Neuroscience, Imaging and Clinical Sciences, "G. d'Annunzio" University, Chieti, Italy
| | | | - Massimo di Giannantonio
- Department of Neuroscience, Imaging and Clinical Sciences, "G. d'Annunzio" University, Chieti, Italy
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14
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Identifying novel biomarkers with TMS-EEG - Methodological possibilities and challenges. J Neurosci Methods 2022; 377:109631. [PMID: 35623474 DOI: 10.1016/j.jneumeth.2022.109631] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 05/09/2022] [Accepted: 05/21/2022] [Indexed: 12/17/2022]
Abstract
Biomarkers are essential for understanding the underlying pathologies in brain disorders and for developing effective treatments. Combined transcranial magnetic stimulation and electroencephalography (TMS-EEG) is an emerging neurophysiological tool that can be used for biomarker development. This method can identify biomarkers associated with the function and dynamics of the inhibitory and excitatory neurotransmitter systems and effective connectivity between brain areas. In this review, we outline the current state of the TMS-EEG biomarker field by summarizing the existing protocols and the possibilities and challenges associated with this methodology.
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15
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Intracortical facilitation and inhibition in human primary motor cortex during motor skill acquisition. Exp Brain Res 2022; 240:3289-3304. [PMID: 36308563 PMCID: PMC9678989 DOI: 10.1007/s00221-022-06496-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 10/20/2022] [Indexed: 01/15/2023]
Abstract
The primary motor cortex (M1) is critical for movement execution, but its role in motor skill acquisition remains elusive. Here, we examine the role of M1 intracortical circuits during skill acquisition. Paired-pulse transcranial magnetic stimulation (TMS) paradigms of short-interval intracortical facilitation (SICF) and inhibition (SICI) were used to assess excitatory and inhibitory circuits, respectively. We hypothesised that intracortical facilitation and inhibition circuits in M1 would be modulated to support acquisition of a novel visuomotor skill. Twenty-two young, neurologically healthy adults trained with their nondominant hand on a skilled and non-skilled sequential visuomotor isometric finger abduction task. Electromyographic recordings were obtained from the nondominant first dorsal interosseous (FDI) muscle. Corticomotor excitability, SICF, and SICI were examined before, at the midway point, and after the 10-block motor training. SICI was assessed using adaptive threshold-hunting procedures. Task performance improved after the skilled, but not non-skilled, task training, which likely reflected the increase in movement speed during training. The amplitudes of late SICF peaks were modulated with skilled task training. There was no modulation of the early SICF peak, SICI, and corticomotor excitability with either task training. There was also no association between skill acquisition and SICF or SICI. The findings indicate that excitatory circuitries responsible for the generation of late SICF peaks, but not the early SICF peak, are modulated in motor skill acquisition for a sequential visuomotor isometric finger abduction task.
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16
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Gurses A, Boran H, Vuralli D, Cengiz B. Weak transcranial direct current effect on i waves: A single motor unit recording study of healthy controls. NEUROL SCI NEUROPHYS 2022. [DOI: 10.4103/nsn.nsn_221_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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17
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Neva JL, Brown KE, Peters S, Feldman SJ, Mahendran N, Boisgontier MP, Boyd LA. Acute Exercise Modulates the Excitability of Specific Interneurons in Human Motor Cortex. Neuroscience 2021; 475:103-116. [PMID: 34487820 DOI: 10.1016/j.neuroscience.2021.08.032] [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: 03/12/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 10/20/2022]
Abstract
Acute exercise can modulate the excitability of the non-exercised upper-limb representation in the primary motor cortex (M1). Accumulating evidence demonstrates acute exercise affects measures of M1 intracortical excitability, with some studies also showing altered corticospinal excitability. However, the influence of distinct M1 interneuron populations on the modulation of intracortical and corticospinal excitability following acute exercise is currently unknown. We assessed the impact of an acute bout of leg cycling exercise on unique M1 interneuron excitability of a non-exercised intrinsic hand muscle using transcranial magnetic stimulation (TMS) in young adults. Specifically, posterior-to-anterior (PA) and anterior-to-posterior (AP) TMS current directions were used to measure the excitability of distinct populations of interneurons before and after an acute bout of exercise or rest. Motor evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) were measured in the PA and AP current directions in M1 at two time points separated by 25 min of rest, as well as immediately and 30 min after a 25-minute bout of moderate-intensity cycling exercise. Thirty minutes after exercise, MEP amplitudes were significantly larger than other timepoints when measured with AP current, whereas MEP amplitudes derived from PA current did not show this effect. Similarly, SICI was significantly decreased immediately following acute exercise measured with AP but not PA current. Our findings suggest that the excitability of unique M1 interneurons are differentially modulated by acute exercise. These results indicate that M1 interneurons preferentially activated by AP current may play an important role in the exercise-induced modulation of intracortical and corticospinal excitability.
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Affiliation(s)
- Jason L Neva
- Université de Montréal, École de kinésiologie et des sciences de l'activité physique, Faculté de médecine, Montréal, QC, Canada; Centre de recherche de l'institut universitaire de gériatrie de Montréal, Montréal, QC, Canada.
| | - Katlyn E Brown
- University of Waterloo, Department of Kinesiology, Applied Health Sciences, Waterloo, ON, Canada
| | - Sue Peters
- Rehabilitation Research Program, GF Strong Rehabilitation Centre, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada; University of British Columbia, Department of Physical Therapy, Faculty of Medicine, Vancouver, BC, Canada
| | - Samantha J Feldman
- Graduate Program in Clinical Developmental Neuropsychology, Department of Psychology, York University, Toronto, ON, Canada
| | - Niruthikha Mahendran
- University of Queensland, Discipline of Physiotherapy, School of Health and Rehabilitation Sciences, Brisbane, Australia
| | - Matthieu P Boisgontier
- School of Rehabilitation Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa ON, Canada; Bruyère Research Institute, Ottawa, ON, Canada
| | - Lara A Boyd
- University of British Columbia, Department of Physical Therapy, Faculty of Medicine, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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18
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Acker G, Giampiccolo D, Rubarth K, Mertens R, Zdunczyk A, Hardt J, Jussen D, Schneider H, Rosenstock T, Mueller V, Picht T, Vajkoczy P. Motor excitability in bilateral moyamoya vasculopathy and the impact of revascularization. Neurosurg Focus 2021; 51:E7. [PMID: 34469868 DOI: 10.3171/2021.6.focus21280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/23/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Motor cortical dysfunction has been shown to be reversible in patients with unilateral atherosclerotic disease after cerebral revascularization. Moyamoya vasculopathy (MMV) is a rare bilateral stenoocclusive cerebrovascular disease. The aim of this study was to analyze the corticospinal excitability and the role of bypass surgery in restoring cortical motor function in patients by using navigated transcranial magnetic stimulation (nTMS). METHODS Patients with bilateral MMV who met the criteria for cerebral revascularization were prospectively included. Corticospinal excitability, cortical representation area, and intracortical inhibition and facilitation were assessed by nTMS for a small hand muscle (first dorsal interosseous) before and after revascularization. The clinically and/or hemodynamically more severely affected hemisphere was operated first as the leading hemisphere. Intra- and interhemispheric differences were analyzed before and after direct or combined revascularization. RESULTS A total of 30 patients with bilateral MMV were examined by nTMS prior to and after revascularization surgery. The corticospinal excitability was higher in the leading hemisphere compared with the non-leading hemisphere prior to revascularization. This hyperexcitability was normalized after revascularization as demonstrated in the resting motor threshold ratio of the hemispheres (preoperative median 0.97 [IQR 0.89-1.08], postoperative median 1.02 [IQR 0.94-1.22]; relative effect = 0.61, p = 0.03). In paired-pulse paradigms, a tendency for a weaker inhibition of the leading hemisphere was observed compared with the non-leading hemisphere. Importantly, the paired paradigm also demonstrated approximation of excitability patterns between the two hemispheres after surgery. CONCLUSIONS The study results suggested that, in the case of a bilateral chronic ischemia, a compensation mechanism between both hemispheres seemed to exist that normalized after revascularization surgery. A potential role of nTMS in predicting the efficacy of revascularization must be further assessed.
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Affiliation(s)
- Gueliz Acker
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin.,2Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin
| | - Davide Giampiccolo
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Kerstin Rubarth
- 2Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin.,3Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biometry and Clinical Epidemiology, Berlin
| | - Robert Mertens
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Anna Zdunczyk
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Juliane Hardt
- 3Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biometry and Clinical Epidemiology, Berlin.,4University of Applied Sciences Hannover, Hochschule Hannover-University of Applied Sciences and Arts, Fakultät III, Department Information and Communication, Medical Information Management, Hannover.,5Department of Biometry, Epidemiology and Information Processing, WHO Collaborating Centre for Research and Training for Health in the Human-Animal-Environment Interface, University of Veterinary Medicine Hannover, Foundation, Hannover; and
| | - Daniel Jussen
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Heike Schneider
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Tizian Rosenstock
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin.,2Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin
| | - Vera Mueller
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
| | - Thomas Picht
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin.,6Cluster of Excellence: "Matters of Activity. Image Space Material," Humboldt University, Berlin, Germany
| | - Peter Vajkoczy
- 1Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurosurgery, Berlin
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19
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Baarbé J, Vesia M, Brown MJN, Lizarraga KJ, Gunraj C, Jegatheeswaran G, Drummond NM, Rinchon C, Weissbach A, Saravanamuttu J, Chen R. Interhemispheric interactions between the right angular gyrus and the left motor cortex: a transcranial magnetic stimulation study. J Neurophysiol 2021; 125:1236-1250. [PMID: 33625938 DOI: 10.1152/jn.00642.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The interconnection of the angular gyrus of right posterior parietal cortex (PPC) and the left motor cortex (LM1) is essential for goal-directed hand movements. Previous work with transcranial magnetic stimulation (TMS) showed that right PPC stimulation increases LM1 excitability, but right PPC followed by left PPC-LM1 stimulation (LPPC-LM1) inhibits LM1 corticospinal output compared with LPPC-LM1 alone. It is not clear if right PPC-mediated inhibition of LPPC-LM1 is due to inhibition of left PPC or to combined effects of right and left PPC stimulation on LM1 excitability. We used paired-pulse TMS to study the extent to which combined right and left PPC stimulation, targeting the angular gyri, influences LM1 excitability. We tested 16 healthy subjects in five paired-pulsed TMS experiments using MRI-guided neuronavigation to target the angular gyri within PPC. We tested the effects of different right angular gyrus (RAG) and LM1 stimulation intensities on the influence of RAG on LM1 and on influence of left angular gyrus (LAG) on LM1 (LAG-LM1). We then tested the effects of RAG and LAG stimulation on LM1 short-interval intracortical facilitation (SICF), short-interval intracortical inhibition (SICI), and long-interval intracortical inhibition (LICI). The results revealed that RAG facilitated LM1, inhibited SICF, and inhibited LAG-LM1. Combined RAG-LAG stimulation did not affect SICI but increased LICI. These experiments suggest that RAG-mediated inhibition of LAG-LM1 is related to inhibition of early indirect (I)-wave activity and enhancement of GABAB receptor-mediated inhibition in LM1. The influence of RAG on LM1 likely involves ipsilateral connections from LAG to LM1 and heterotopic connections from RAG to LM1.NEW & NOTEWORTHY Goal-directed hand movements rely on the right and left angular gyri (RAG and LAG) and motor cortex (M1), yet how these brain areas functionally interact is unclear. Here, we show that RAG stimulation facilitated right hand motor output from the left M1 but inhibited indirect (I)-waves in M1. Combined RAG and LAG stimulation increased GABAB, but not GABAA, receptor-mediated inhibition in left M1. These findings highlight unique brain interactions between the RAG and left M1.
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Affiliation(s)
- Julianne Baarbé
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Michael Vesia
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Matt J N Brown
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan.,Department of Kinesiology, California State University, Sacramento, California
| | - Karlo J Lizarraga
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan.,Motor Physiology and Neuromodulation Program, Division of Movement Disorders and Center for Health + Technology, Department of Neurology, University of Rochester, Rochester, New York
| | - Carolyn Gunraj
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Gaayathiri Jegatheeswaran
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Neil M Drummond
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Cricia Rinchon
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Anne Weissbach
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan.,Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - James Saravanamuttu
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Robert Chen
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,School of Kinesiology, Brain Behavior Laboratory, University of Michigan, Ann Arbor, Michigan
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20
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Germann M, Baker SN. Evidence for Subcortical Plasticity after Paired Stimulation from a Wearable Device. J Neurosci 2021; 41:1418-1428. [PMID: 33441436 PMCID: PMC7896019 DOI: 10.1523/jneurosci.1554-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 11/21/2022] Open
Abstract
Existing non-invasive stimulation protocols can generate plasticity in the motor cortex and its corticospinal projections; techniques for inducing plasticity in subcortical circuits and alternative descending pathways such as the reticulospinal tract (RST) are less well developed. One possible approach developed by this laboratory pairs electrical muscle stimulation with auditory clicks, using a wearable device to deliver stimuli during normal daily activities. In this study, we applied a variety of electrophysiological assessments to male and female healthy human volunteers during a morning and evening laboratory visit. In the intervening time (∼6 h), subjects wore the stimulation device, receiving three different protocols, in which clicks and stimulation of the biceps muscle were paired at either low or high rate, or delivered at random. Paired stimulation: (1) increased the extent of reaction time shortening by a loud sound (the StartReact effect); (2) decreased the suppression of responses to transcranial magnetic brain stimulation (TMS) following a loud sound; (3) enhanced muscle responses elicited by a TMS coil oriented to induce anterior-posterior (AP) current, but not posterior-anterior (PA) current, in the brain. These measurements have all been suggested to be sensitive to subcortical, possibly reticulospinal, activity. Changes were similar for either of the two paired stimulus rates tested, but absent after unpaired (control) stimulation. Taken together, these results suggest that pairing clicks and muscle stimulation for long periods does indeed induce plasticity in subcortical systems such as the RST.SIGNIFICANCE STATEMENT Subcortical systems such as the reticulospinal tract (RST) are important motor pathways, which can make a significant contribution to functional recovery after cortical damage such as stroke. Here, we measure changes produced after a novel non-invasive stimulation protocol, which uses a wearable device to stimulate for extended periods. We observed changes in electrophysiological measurements consistent with the induction of subcortical plasticity. This protocol may prove an important tool for enhancing motor rehabilitation, in situations where insufficient cortical tissue survives to be a plausible substrate for recovery of function.
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Affiliation(s)
- Maria Germann
- Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Stuart N Baker
- Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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21
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Nikolov P, Zimmermann JV, Hassan SS, Albrecht P, Schnitzler A, Groiss SJ. Impact of the number of conditioning pulses on motor cortex excitability: a transcranial magnetic stimulation study. Exp Brain Res 2020; 239:583-589. [PMID: 33373012 PMCID: PMC7936961 DOI: 10.1007/s00221-020-06010-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/07/2020] [Indexed: 12/03/2022]
Abstract
Conditioning transcranial magnetic stimulation (TMS) with subthreshold conditioning stimulus followed by supra-threshold test stimulus at inter-stimulus intervals (ISI) of 1–5 ms results in inhibition (SICI), while ISI at 10–15 ms results in facilitation (ICF). One concerning issue, applying ICF/SICI protocols on patients is the substantial protocol variability. Here, we hypothesized that increasing the number of CS could result in more robust ICF/SICI protocols. Twenty healthy subjects participated in the study. Motor-evoked potentials (MEP) were obtained from conditioning TMS with a varying number of conditioning stimuli in 3, 4, 10, and 15 ms ISI over the primary motor cortex. MEP amplitudes were then compared to examine excitability. TMS with 3, 5, and 7 conditioning stimuli but not with one conditioning stimulus induced ICF. Moreover, 10 ms ISI produced stronger ICF than 15 ms ISI. Significant SICI was only induced with one conditioning stimulus. Besides, 3 ms ISI resulted in stronger SICI than 4 ms ISI. Only a train of conditioning stimuli induced stable ICF and may be more advantageous than the classical paired pulse ICF paradigm.
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Affiliation(s)
- Petyo Nikolov
- Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Johanna V Zimmermann
- Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Shady S Hassan
- Department of Neurology, Medical Faculty, Assiut University Hospital, Assiut, Egypt
| | - Philipp Albrecht
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stefan J Groiss
- Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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22
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Opie GM, Semmler JG. Preferential Activation of Unique Motor Cortical Networks With Transcranial Magnetic Stimulation: A Review of the Physiological, Functional, and Clinical Evidence. Neuromodulation 2020; 24:813-828. [PMID: 33295685 DOI: 10.1111/ner.13314] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/30/2020] [Accepted: 10/19/2020] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The corticospinal volley produced by application of transcranial magnetic stimulation (TMS) over primary motor cortex consists of a number of waves generated by trans-synaptic input from interneuronal circuits. These indirect (I)-waves mediate the sensitivity of TMS to cortical plasticity and intracortical excitability and can be assessed by altering the direction of cortical current induced by TMS. While this methodological approach has been conventionally viewed as preferentially recruiting early or late I-wave inputs from a given populations of neurons, growing evidence suggests recruitment of different neuronal populations, and this would strongly influence interpretation and application of these measures. The aim of this review is therefore to consider the physiological, functional, and clinical evidence for the independence of the neuronal circuits activated by different current directions. MATERIALS AND METHODS To provide the relevant context, we begin with an overview of TMS methodology, focusing on the different techniques used to quantify I-waves. We then comprehensively review the literature that has used variations in coil orientation to investigate the I-wave circuits, grouping studies based on the neurophysiological, functional, and clinical relevance of their outcomes. RESULTS Review of the existing literature reveals significant evidence supporting the idea that varying current direction can recruit different neuronal populations having unique functionally and clinically relevant characteristics. CONCLUSIONS Further research providing greater characterization of the I-wave circuits activated with different current directions is required. This will facilitate the development of interventions that are able to modulate specific intracortical circuits, which will be an important application of TMS.
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Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
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23
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Pisa M, Chieffo R, Congiu M, Dalla Costa G, Esposito F, Romeo M, Comola M, Comi G, Leocani L. Intracortical motor conduction is associated with hand dexterity in progressive multiple sclerosis. Mult Scler 2020; 27:1222-1229. [PMID: 32975472 DOI: 10.1177/1352458520960374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Hand dexterity dysfunction is a key feature of disability in people with progressive multiple sclerosis (PMS). It underlies corticospinal tract (CST) and cerebellar integrity, as well as disruption of cortical networks, which are hardly assessed by standard techniques. Transcranial magnetic stimulation is a promising tool for evaluating the integrity of intracortical motor pathways. OBJECTIVE To investigate neurophysiological correlates of motor hand impairment in PMS. METHODS Antero-posterior (AP) stimulation of the primary motor cortex activates the CST indirectly through polysynaptic pathways, while a direct CST activation occurs with latero-medial (LM) directed current. Thirty PMS and 15 healthy controls underwent dominant hand motor evoked potentials (MEP) using AP and LM-directed stimulation, and a clinical assessment of dexterity (nine-hole peg test) and strength (MRC scale, grip and pinch). RESULTS PMS with AP-LM latency difference 2.5 standard deviation above the mean of controls (33%) showed worse dexterity but no difference in upper limb strength. Accordingly, AP-LM latency shortening predicted dexterity (R2 = 0.538, p < 0.001), but not strength impairment. On the contrary, absolute MEP latencies only correlated with strength (grip: R2 = 0.381, p = 0.014; MRC: R2 = 0.184, p = 0.041). CONCLUSION AP-LM latency shortening may be used to assess the integrity polysynaptic intracortical networks implicated in dexterity impairment.
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Affiliation(s)
- Marco Pisa
- University Vita-Salute San Raffaele, Milan, Italy/Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy/Experimental Neurophysiology Unit, The Institute of Experimental Neurology (INSPE), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Raffaella Chieffo
- Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy/Experimental Neurophysiology Unit, The Institute of Experimental Neurology (INSPE), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Martina Congiu
- Experimental Neurophysiology Unit, The Institute of Experimental Neurology (INSPE), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Gloria Dalla Costa
- University Vita-Salute San Raffaele, Milan, Italy/Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Federica Esposito
- Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Marzia Romeo
- Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Mauro Comola
- Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Giancarlo Comi
- University Vita-Salute San Raffaele, Milan, Italy/Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy/Experimental Neurophysiology Unit, The Institute of Experimental Neurology (INSPE), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Letizia Leocani
- University Vita-Salute San Raffaele, Milan, Italy/Department of Neurorehabilitation, IRCCS Ospedale San Raffaele, Milan, Italy/Experimental Neurophysiology Unit, The Institute of Experimental Neurology (INSPE), IRCCS Ospedale San Raffaele, Milan, Italy
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24
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Abstract
I-waves represent high-frequency (~ 600 Hz) repetitive discharge of corticospinal fibers elicited by single-pulse stimulation of motor cortex. First detected and examined in animal preparations, this multiple discharge can also be recorded in humans from the corticospinal tract with epidural spinal electrodes. The exact underpinning neurophysiology of I-waves is still unclear, but there is converging evidence that they originate at the cortical level through synaptic input from specific excitatory interneuronal circuitries onto corticomotoneuronal cells, controlled by GABAAergic interneurons. In contrast, there is at present no supportive evidence for the alternative hypothesis that I-waves are generated by high-frequency oscillations of the membrane potential of corticomotoneuronal cells upon initial strong depolarization. Understanding I-wave physiology is essential for understanding how TMS activates the motor cortex.
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Affiliation(s)
- Ulf Ziemann
- Department of Neurology and Stroke, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany.
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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25
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Hand BJ, Opie GM, Sidhu SK, Semmler JG. TMS coil orientation and muscle activation influence lower limb intracortical excitability. Brain Res 2020; 1746:147027. [PMID: 32717277 DOI: 10.1016/j.brainres.2020.147027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/26/2020] [Accepted: 07/19/2020] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Previous research with transcranial magnetic stimulation (TMS) indicates that coil orientation (TMS current direction) and muscle activation state (rest or active) modify corticospinal and intracortical excitability of upper limb muscles. However, the extent to which these factors influence corticospinal and intracortical excitability of lower limb muscles is unknown. This study aimed to examine how variations in coil orientation and muscle activation affect corticospinal and intracortical excitability of tibialis anterior (TA), a lower leg muscle. METHODS In 21 young (21.6 ± 3.3 years, 11 female) adults, TMS was administered to the motor cortical representation of TA in posterior-anterior (PA) and mediolateral (ML) orientations at rest and during muscle activation. Single-pulse TMS measures of motor evoked potential amplitude, in addition to resting and active motor thresholds, were used to index corticospinal excitability, whereas paired-pulse TMS measures of short-interval intracortical inhibition (SICI) and facilitation (SICF), and long-interval intracortical inhibition (LICI), were used to assess excitability of intracortical circuits. RESULTS For single-pulse TMS, motor thresholds and test TMS intensity were lower for ML stimulation (all P < 0.05). In a resting muscle, ML TMS produced greater SICI (P < 0.001) and less SICF (both P < 0.05) when compared with PA TMS. In contrast, ML TMS in an active muscle resulted in reduced SICI but increased SICF (both P ≤ 0.001) when compared with PA TMS. CONCLUSION TMS coil orientation and muscle activation influence measurements of intracortical excitability recorded in the tibialis anterior, and are therefore important considerations in TMS studies of lower limb muscles.
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Affiliation(s)
- Brodie J Hand
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - Simranjit K Sidhu
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia.
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26
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Spampinato D. Dissecting two distinct interneuronal networks in M1 with transcranial magnetic stimulation. Exp Brain Res 2020; 238:1693-1700. [PMID: 32661650 PMCID: PMC7413864 DOI: 10.1007/s00221-020-05875-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 07/06/2020] [Indexed: 11/27/2022]
Abstract
Interactions from both inhibitory and excitatory interneurons are necessary components of cortical processing that contribute to the vast amount of motor actions executed by humans daily. As transcranial magnetic stimulation (TMS) over primary motor cortex is capable of activating corticospinal neurons trans-synaptically, studies over the past 30 years have provided how subtle changes in stimulation parameters (i.e., current direction, pulse width, and paired-pulse) can elucidate evidence for two distinct neuronal networks that can be probed with this technique. This article provides a brief review of some fundamental studies demonstrating how these networks have separable excitatory inputs to corticospinal neurons. Furthermore, the findings of recent investigations will be discussed in detail, illustrating how each network's sensitivity to different brain states (i.e., rest, movement preparation, and motor learning) is dissociable. Understanding the physiological characteristics of each network can help to explain why interindividual responses to TMS exist, while also providing insights into the role of these networks in various human motor behaviors.
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Affiliation(s)
- Danny Spampinato
- Department for Clinical and Movement Neurosciences, Institute of Neurology, University College of London, London, UK.
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27
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Cretu AL, Ruddy KL, Post A, Wenderoth N. Muscle-specific modulation of indirect inputs to primary motor cortex during action observation. Exp Brain Res 2020; 238:1735-1744. [PMID: 32266444 DOI: 10.1007/s00221-020-05801-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/25/2020] [Indexed: 01/22/2023]
Abstract
Single-pulse transcranial magnetic stimulation (spTMS) studies report that movement observation facilitates corticospinal excitability in primary motor cortex (M1) in a muscle-specific manner. However, motor evoked potentials (MEPs) elicited by spTMS are known to reflect the summation of several descending volleys in corticospinal neurons which are evoked via mono- and polysynaptic inputs (so-called indirect waves or I-waves). It is unclear which of these components contribute to the muscle-specific modulation of M1 during action observation. The interactions between different I-waves are reflected in the facilitatory peaks elicited with a short-intracortical facilitation (SICF) protocol when two pulses are sent to M1 at precise intervals (i.e., 1.3, 2.5 or 4.1 ms). Here, we explored the modulation of early and late SICF peaks during action observation by measuring highly specific MEP amplitude changes measured in two muscles (index, FDI and little finger, ADM) while participants observed two different actions (precision and whole-hand grip). Our results demonstrate that both early (1.3 ms) and late (2.5 and 4.1 ms) SICF peaks are modulated in the context of movement observation. However, only the second peak (ISI 2.5 ms) was significantly associated with the muscle-specific modulation of corticospinal excitability as measured with spTMS. This late SICF peak is believed to reflect the activity cortico-cortical pathways involved in the facilitation of muscle-specific representations in M1. Thus, our findings suggest that movement observation leads to widespread activation of different neural circuits within M1, including those mediating cortico-cortical communication.
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Affiliation(s)
- Andreea Loredana Cretu
- Neural Control of Movement Lab, Department of Health Science and Technology, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland.
| | - Kathy L Ruddy
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Alain Post
- Neural Control of Movement Lab, Department of Health Science and Technology, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Nicole Wenderoth
- Neural Control of Movement Lab, Department of Health Science and Technology, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
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28
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Opie GM, Hand BJ, Semmler JG. Age-related changes in late synaptic inputs to corticospinal neurons and their functional significance: A paired-pulse TMS study. Brain Stimul 2020; 13:239-246. [DOI: 10.1016/j.brs.2019.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/01/2019] [Accepted: 08/05/2019] [Indexed: 01/30/2023] Open
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29
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Rossini P, Di Iorio R, Bentivoglio M, Bertini G, Ferreri F, Gerloff C, Ilmoniemi R, Miraglia F, Nitsche M, Pestilli F, Rosanova M, Shirota Y, Tesoriero C, Ugawa Y, Vecchio F, Ziemann U, Hallett M. Methods for analysis of brain connectivity: An IFCN-sponsored review. Clin Neurophysiol 2019; 130:1833-1858. [DOI: 10.1016/j.clinph.2019.06.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 05/08/2019] [Accepted: 06/18/2019] [Indexed: 01/05/2023]
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30
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Sun ZG, Pi YL, Zhang J, Wang M, Zou J, Wu W. Effect of acupuncture at ST36 on motor cortical excitation and inhibition. Brain Behav 2019; 9:e01370. [PMID: 31359627 PMCID: PMC6749473 DOI: 10.1002/brb3.1370] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/20/2019] [Accepted: 07/01/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Acupuncture at Zusanli (ST36) is often used to facilitate motor recovery after stroke. However, the effect of acupuncture at ST36 on motor cortical excitation and inhibition remains unclear. This study aimed to explore the effect of acupuncture at ST36 on motor cortical excitation and inhibition. METHODS Twenty healthy volunteers were recruited to receive acupuncture treatment. We selected the acupoint ST36 and its respective sham point as the experimental acupoint. Transcranial magnetic stimulation (TMS) was used to measure motor-evoked potentials (MEP) at 7 time points-before acupuncture (Pre), acupuncture (T0), 4 and 8 min after acupuncture (T4; T8), needle removal (T12), 4 and 8 min after needle removal (T16; T20). Simultaneously, paired TMS (pTMS) was employed to measure short- and long-interval intracortical inhibition (SICI [short latency intracortical inhibition]; LICI [long latency intracortical inhibition]), respectively, at three time points-before acupuncture (Pre), acupuncture (T0), needle removal (T12). After removing the acupuncture needle, all subjects were asked to quantify their Deqi sensation using a Gas table. RESULTS The average Deqi sensation score of all subjects during acupuncture at ST36 was higher than that observed at the sham point. With acupuncture at ST36, the MEP amplitude was higher at three time points (T0, T4, T8) than at Pre, although the MEP amplitude tended toward Pre after needle removal. The MEP amplitude was also higher at the same time points (T0, T4, T8) than at the sham point. Furthermore, the Deqi sensation score was correlated with MEP amplitude. With acupuncture at ST36, SICI and LICI at T0 were higher than those at Pre, and SICI and LICI at T0 were higher than those at the sham point. CONCLUSION Acupuncture at ST36 increased motor cortical excitation and had an effect on the remaining needle phase. Deqi sensation was correlated with MEP amplitude. Acupuncture at ST36 also decreased motor cortical inhibition.
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Affiliation(s)
- Zhong-Guang Sun
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Yan-Ling Pi
- Shanghai Punan Hospital of Pudong New District, Shanghai, China
| | - Jian Zhang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Miao Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Jun Zou
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Wei Wu
- Affiliated Competitive Sport School, Shanghai University of Sport, Shanghai, China
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31
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Khademi F, Royter V, Gharabaghi A. Distinct Beta-band Oscillatory Circuits Underlie Corticospinal Gain Modulation. Cereb Cortex 2019; 28:1502-1515. [PMID: 29415124 PMCID: PMC6093341 DOI: 10.1093/cercor/bhy016] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 01/09/2018] [Indexed: 01/13/2023] Open
Abstract
Rhythmic synchronization of neurons is known to affect neuronal interactions. In the motor system, oscillatory power fluctuations modulate corticospinal excitability. However, previous research addressing phase-specific gain modulation in the motor system has resulted in contradictory findings. It remains unclear how many time windows of increased responsiveness each oscillatory cycle provides. Moreover, we still lack conclusive evidence as to whether the motor cortex entails an intrinsic response modulation along the rhythm cycle, as shown for spinal neurons. We investigated this question with single-pulse transcranial magnetic stimulation over the primary motor cortex at rest. Application of near-motor threshold stimuli revealed a frequency- and phase-specific gain modulation at both cortical and spinal level, independent of the spontaneous oscillatory power fluctuations at each level. We detected bilateral sensorimotor circuits in the lower beta-band (14–17 Hz) and unilateral corticospinal circuits in the upper beta-band (20–24 Hz). These findings provide novel evidence that intrinsic activity in the human motor cortex modulates input gain along the beta oscillatory cycle within distinct circuits. In accordance with periodic alternations of synchronous hyper- and depolarization, increased neuronal responsiveness occurred once per oscillatory beta cycle. This information may lead to new brain state-dependent and circuit-specific interventions for targeted neuromodulation.
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Affiliation(s)
- Fatemeh Khademi
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, 72076 Tuebingen, Germany
| | - Vladimir Royter
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, 72076 Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, 72076 Tuebingen, Germany
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32
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Kurz A, Xu W, Wiegel P, Leukel C, N. Baker S. Non-invasive assessment of superficial and deep layer circuits in human motor cortex. J Physiol 2019; 597:2975-2991. [PMID: 31045242 PMCID: PMC6636705 DOI: 10.1113/jp277849] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/01/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The first indirect (I) corticospinal volley from stimulation of the motor cortex consists of two parts: one that originates from infragranular layer 5 and a subsequent part with a delay of 0.6 ms to which supragranular layers contribute. Non-invasive probing of these two parts was performed in humans using a refined electrophysiological method involving transcranial magnetic stimulation and peripheral nerve stimulation. Activity modulation of these two parts during a sensorimotor discrimination task was consistent with previous results in monkeys obtained with laminar recordings. ABSTRACT Circuits in superficial and deep layers play distinct roles in cortical computation, but current methods to study them in humans are limited. Here, we developed a novel approach for non-invasive assessment of layer-specific activity in the human motor cortex. We first conducted brain slice and in vivo experiments on monkey motor cortex to investigate the output timing from layer 5 (including corticospinal neurons) following extracellular stimulation. Neuron responses contained cyclical waves. The first wave was composed of two parts: the earliest part originated only from stimulation of layer 5; after 0.6 ms, stimuli to superficial layers 2/3 could also contribute. In healthy humans we then assessed different parts of the first corticospinal volley elicited by transcranial magnetic stimulation (TMS), by interacting TMS with stimulation of the median nerve generating an H-reflex. By adjusting the delay between stimuli, we could assess the earliest volley evoked by TMS, and the part 0.6 ms later. Measurements were made while subjects performed a visuo-motor discrimination task, which has been previously shown in monkey to modulate superficial motor cortical cells selectively depending on task difficulty. We showed a similar selective modulation of the later part of the TMS volley, as expected if this part of the volley is sensitive to superficial cortical excitability. We conclude that it is possible to segregate different cortical circuits which may refer to different motor cortex layers in humans, by exploiting small time differences in the corticospinal volleys evoked by non-invasive stimulation.
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Affiliation(s)
- Alexander Kurz
- Department of Sport ScienceUniversity of FreiburgFreiburg79117Germany
- Bernstein Center FreiburgUniversity of FreiburgFreiburg79104Germany
| | - Wei Xu
- Medical SchoolInstitute of NeuroscienceNewcastle UniversityNewcastle upon TyneNE2 4HHUK
| | - Patrick Wiegel
- Department of Sport ScienceUniversity of FreiburgFreiburg79117Germany
- Bernstein Center FreiburgUniversity of FreiburgFreiburg79104Germany
| | - Christian Leukel
- Department of Sport ScienceUniversity of FreiburgFreiburg79117Germany
- Bernstein Center FreiburgUniversity of FreiburgFreiburg79104Germany
| | - Stuart N. Baker
- Medical SchoolInstitute of NeuroscienceNewcastle UniversityNewcastle upon TyneNE2 4HHUK
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Guggisberg AG, Koch PJ, Hummel FC, Buetefisch CM. Brain networks and their relevance for stroke rehabilitation. Clin Neurophysiol 2019; 130:1098-1124. [PMID: 31082786 DOI: 10.1016/j.clinph.2019.04.004] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 03/04/2019] [Accepted: 04/08/2019] [Indexed: 12/21/2022]
Abstract
Stroke has long been regarded as focal disease with circumscribed damage leading to neurological deficits. However, advances in methods for assessing the human brain and in statistics have enabled new tools for the examination of the consequences of stroke on brain structure and function. Thereby, it has become evident that stroke has impact on the entire brain and its network properties and can therefore be considered as a network disease. The present review first gives an overview of current methodological opportunities and pitfalls for assessing stroke-induced changes and reorganization in the human brain. We then summarize principles of plasticity after stroke that have emerged from the assessment of networks. Thereby, it is shown that neurological deficits do not only arise from focal tissue damage but also from local and remote changes in white-matter tracts and in neural interactions among wide-spread networks. Similarly, plasticity and clinical improvements are associated with specific compensatory structural and functional patterns of neural network interactions. Innovative treatment approaches have started to target such network patterns to enhance recovery. Network assessments to predict treatment response and to individualize rehabilitation is a promising way to enhance specific treatment effects and overall outcome after stroke.
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Affiliation(s)
- Adrian G Guggisberg
- Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital Geneva, Switzerland.
| | - Philipp J Koch
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL), 1202 Geneva, Switzerland; Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology Valais (EPFL Valais), Clinique Romande de Réadaptation, 1951 Sion, Switzerland
| | - Friedhelm C Hummel
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL), 1202 Geneva, Switzerland; Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology Valais (EPFL Valais), Clinique Romande de Réadaptation, 1951 Sion, Switzerland; Department of Clinical Neuroscience, University Hospital Geneva, 1202 Geneva, Switzerland
| | - Cathrin M Buetefisch
- Depts of Neurology, Rehabilitation Medicine, Radiology, Emory University, Atlanta, GA, USA
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Combined endogenous and exogenous disinhibition of intracortical circuits augments plasticity induction in the human motor cortex. Brain Stimul 2019; 12:1027-1040. [PMID: 30894281 DOI: 10.1016/j.brs.2019.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/03/2019] [Accepted: 03/08/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Motor imagery (MI) engages cortical areas in the human brain similar to motor practice. Corticospinal excitability (CSE) is facilitated during but not after MI practice. We hypothesized that lasting CSE changes could be achieved by associatively pairing this endogenous modulation with exogenous stimulation of the same intracortical circuits. METHODS We combined MI with a disinhibition protocol (DIS) targeting intracortical circuits by paired-pulse repetitive transcranial magnetic stimulation in one main and three subsequent experiments. The follow-up experiments were applied to increase effects, e.g., by individualizing inter-stimulus intervals, adding neuromuscular stimulation and expanding the intervention period. CSE was captured during (online) and after (offline) the interventions via input-output changes and cortical maps of motor evoked potentials. A total of 35 healthy subjects (mean age 26.1 ± 2.6 years, 20 females) participated in this study. RESULTS A short intervention (48 stimuli within ∼90s) increased CSE. This plasticity developed rapidly, was associative (with MIon, but not MIoff or REST) and persisted beyond the intervention period. Follow-up experiments revealed the relevance of individualizing inter-stimulus intervals and of consistent inter-burst periods for online and offline effects, respectively. Expanding this combined MI/DIS intervention to 480 stimuli amplified the sustainability of CSE changes. When concurrent neuromuscular electrical stimulation was applied, the plasticity induction was cancelled. CONCLUSIONS This novel associative stimulation protocol augmented plasticity induction in the human motor cortex within a remarkably short period of time and in the absence of active movements. The combination of endogenous and exogenous disinhibition of intracortical circuits may provide a therapeutic backdoor when active movements are no longer possible, e.g., for hand paralysis after stroke.
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Agarwal S, Koch G, Hillis AE, Huynh W, Ward NS, Vucic S, Kiernan MC. Interrogating cortical function with transcranial magnetic stimulation: insights from neurodegenerative disease and stroke. J Neurol Neurosurg Psychiatry 2019; 90:47-57. [PMID: 29866706 DOI: 10.1136/jnnp-2017-317371] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 05/07/2018] [Accepted: 05/07/2018] [Indexed: 12/11/2022]
Abstract
Transcranial magnetic stimulation (TMS) is an accessible, non-invasive technique to study cortical function in vivo. TMS studies have provided important pathophysiological insights across a range of neurodegenerative disorders and enhanced our understanding of brain reorganisation after stroke. In neurodegenerative disease, TMS has provided novel insights into the function of cortical output cells and the related intracortical interneuronal networks. Characterisation of cortical hyperexcitability in amyotrophic lateral sclerosis and altered motor cortical function in frontotemporal dementia, demonstration of cholinergic deficits in Alzheimer's disease and Parkinson's disease are key examples where TMS has led to advances in understanding of disease pathophysiology and potential mechanisms of propagation, with the potential for diagnostic applications. In stroke, TMS methodology has facilitated the understanding of cortical reorganisation that underlie functional recovery. These insights are critical to the development of effective and targeted rehabilitation strategies in stroke. The present review will provide an overview of cortical function measures obtained using TMS and how such measures may provide insight into brain function. Through an improved understanding of cortical function across a range of neurodegenerative disorders, and identification of changes in neural structure and function associated with stroke that underlie clinical recovery, more targeted therapeutic approaches may now be developed in an evolving era of precision medicine.
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Affiliation(s)
- Smriti Agarwal
- Brain and Mind Centre, University of Sydney, and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Giacomo Koch
- Non-Invasive Brain Stimulation Unit, Neurologia Clinica e Comportamentale, Fondazione Santa Lucia IRCCS, Rome, Italy.,Stroke Unit, Department of Neuroscience, Policlinico Tor Vergata, Rome, Italy
| | - Argye E Hillis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cognitive Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - William Huynh
- Brain and Mind Centre, University of Sydney, and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Nick S Ward
- Sobell Department of Motor Neuroscience, UCL Institute of Neurology, University College London, London, UK.,UCL Partners Centre for Neurorehabilitation, UCL Institute of Neurology, University College London, London, UK.,The National Hospital for Neurology and Neurosurgery, London, UK
| | - Steve Vucic
- Westmead Clinical School, University of Sydney, Sydney, Australia
| | - Matthew C Kiernan
- Brain and Mind Centre, University of Sydney, and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
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Pellegrini M, Zoghi M, Jaberzadeh S. The effect of transcranial magnetic stimulation test intensity on the amplitude, variability and reliability of motor evoked potentials. Brain Res 2018; 1700:190-198. [DOI: 10.1016/j.brainres.2018.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/14/2018] [Accepted: 09/04/2018] [Indexed: 10/28/2022]
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Davila-Pérez P, Jannati A, Fried PJ, Cudeiro Mazaira J, Pascual-Leone A. The Effects of Waveform and Current Direction on the Efficacy and Test-Retest Reliability of Transcranial Magnetic Stimulation. Neuroscience 2018; 393:97-109. [PMID: 30300705 PMCID: PMC6291364 DOI: 10.1016/j.neuroscience.2018.09.044] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/26/2018] [Accepted: 09/28/2018] [Indexed: 12/31/2022]
Abstract
The pulse waveform and current direction of transcranial magnetic stimulation (TMS) influence its interactions with the neural substrate; however, their role in the efficacy and reliability of single- and paired-pulse TMS measures is not fully understood. We investigated how pulse waveform and current direction affect the efficacy and test-retest reliability of navigated, single- and paired-pulse TMS measures. 23 healthy adults (aged 18-35 years) completed two identical TMS sessions, assessing resting motor threshold (RMT), motor-evoked potentials (MEPs), cortical silent period (cSP), short- and long-interval intra-cortical inhibition (SICI and LICI), and intracortical facilitation (ICF) using either monophasic posterior-anterior (monoPA; n = 9), monophasic anterior-posterior (monoAP; n = 7), or biphasic (biAP-PA; n = 7) pulses. Averages of each TMS measure were compared across the three groups and intraclass correlation coefficients were calculated to assess test-retest reliability. RMT was the lowest and cSP was the longest with biAP-PA pulses, whereas MEP latency was the shortest with monoPA pulses. SICI and LICI had the largest effect with monoPA pulses, whereas only monoAP and biAP-PA pulses resulted in significant ICF. MEP amplitude was more reliable with either monoPA or monoAP than with biAP-PA pulses. LICI was the most reliable with monoAP pulses, whereas ICF was the most reliable with biAP-PA pulses. Waveform/current direction influenced RMT, MEP latency, cSP, SICI, LICI, and ICF, as well as the reliability of MEP amplitude, LICI, and ICF. These results show the importance of considering TMS pulse parameters for optimizing the efficacy and reliability of TMS neurophysiologic measures.
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Affiliation(s)
- Paula Davila-Pérez
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Neuroscience and Motor Control Group (NEUROcom), Institute for Biomedical Research (INIBIC), Universidade da Coruña, A Coruña, Spain.
| | - Ali Jannati
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Peter J Fried
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Javier Cudeiro Mazaira
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Neuroscience and Motor Control Group (NEUROcom), Institute for Biomedical Research (INIBIC), Universidade da Coruña, A Coruña, Spain; Centro de Estimulación Cerebral de Galicia, A Coruña, Spain
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Institut Guttman de Neurorehabilitació, Universitat Autónoma de Barcelona, Badalona, Barcelona, Spain.
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Saumur TM, Mochizuki G. Single pulse TMS during preparation for lower limb movement: Effect of task predictability on corticospinal excitability. Brain Res 2018; 1697:105-112. [DOI: 10.1016/j.brainres.2018.07.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/29/2018] [Accepted: 07/23/2018] [Indexed: 11/25/2022]
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Ni Z, Cash RFH, Gunraj C, Bercovici E, Hallett M, Chen R. Involvement of different neuronal components in the induction of cortical plasticity with associative stimulation. Brain Stimul 2018; 12:84-86. [PMID: 30205951 DOI: 10.1016/j.brs.2018.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Paired associative stimulation (PAS), with stimulus interval of 21.5 or 25 ms, using transcranial magnetic stimulation in the posterior-anterior (PA) current direction, produces a long-term-potentiation-like effect. Stimulation with PA directed current generates both early and late indirect (I)-waves while that in anterior-posterior (AP) current predominantly elicits late I-waves. Short interval intracortical inhibition (SICI) inhibits late I-waves but not early I-waves. OBJECTIVE To investigate how cortical inhibition modulates the effects of PAS. METHODS PAS at stimulus interval of 21.5 ms conditioned by SICI (SICI-PAS) was compared to PAS alone with both PA and AP directed currents. RESULTS PAS with both current directions increased cortical excitability. SICI-PAS increased cortical excitability in the PA but not the AP current direction. CONCLUSIONS Both early and late I-waves circuits can mediate cortical PAS plasticity under different conditions. Plasticity induction with the late but not the early I-wave circuits is blocked by SICI.
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Affiliation(s)
- Zhen Ni
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Human motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA
| | - Robin F H Cash
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Monash Alfred Psychiatry Research Centre, Monash University Central Clinical School and The Alfred, Melbourne, VIC, Australia
| | - Carolyn Gunraj
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Eduard Bercovici
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Mark Hallett
- Human motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, USA
| | - Robert Chen
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
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Hanlon CA, Dowdle LT, Henderson JS. Modulating Neural Circuits with Transcranial Magnetic Stimulation: Implications for Addiction Treatment Development. Pharmacol Rev 2018; 70:661-683. [PMID: 29945899 PMCID: PMC6020107 DOI: 10.1124/pr.116.013649] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although the last 50 years of clinical and preclinical research have demonstrated that addiction is a brain disease, we still have no neural circuit-based treatments for substance dependence or cue reactivity at large. Now, for the first time, it appears that a noninvasive brain stimulation technique known as transcranial magnetic stimulation (TMS), which is Food and Drug Administration approved to treat depression, may be the first tool available to fill this critical void in addiction treatment development. The goals of this review are to 1) introduce TMS as a tool to induce causal change in behavior, cortical excitability, and frontal-striatal activity; 2) describe repetitive TMS (rTMS) as an interventional tool; 3) provide an overview of the studies that have evaluated rTMS as a therapeutic tool for alcohol and drug use disorders; and 4) outline a conceptual framework for target selection when designing future rTMS clinical trials in substance use disorders. The manuscript concludes with some suggestions for methodological innovation, specifically with regard to combining rTMS with pharmacotherapy as well as cognitive behavioral training paradigms. We have attempted to create a comprehensive manuscript that provides the reader with a basic set of knowledge and an introduction to the primary experimental questions that will likely drive the field of TMS treatment development forward for the next several years.
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Affiliation(s)
- Colleen A Hanlon
- Departments of Psychiatry (C.A.H., L.T.D., J.S.H.) and Neurosciences (C.A.H., L.T.D.), Medical University of South Carolina, Charleston, South Carolina; and Ralph Johnson VA Medical Center, Charleston, South Carolina (C.A.H.)
| | - Logan T Dowdle
- Departments of Psychiatry (C.A.H., L.T.D., J.S.H.) and Neurosciences (C.A.H., L.T.D.), Medical University of South Carolina, Charleston, South Carolina; and Ralph Johnson VA Medical Center, Charleston, South Carolina (C.A.H.)
| | - J Scott Henderson
- Departments of Psychiatry (C.A.H., L.T.D., J.S.H.) and Neurosciences (C.A.H., L.T.D.), Medical University of South Carolina, Charleston, South Carolina; and Ralph Johnson VA Medical Center, Charleston, South Carolina (C.A.H.)
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Opie GM, Cirillo J, Semmler JG. Age-related changes in late I-waves influence motor cortex plasticity induction in older adults. J Physiol 2018; 596:2597-2609. [PMID: 29667190 DOI: 10.1113/jp274641] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 04/16/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The response to neuroplasticity interventions using transcranial magnetic stimulation (TMS) is reduced in older adults, which may be due, in part, to age-related alterations in interneuronal (I-wave) circuitry. The current study investigated age-related changes in interneuronal characteristics and whether they influence motor cortical plasticity in older adults. While I-wave recruitment was unaffected by age, there was a shift in the temporal characteristics of the late, but not the early I-waves. Using I-wave periodicity repetitive TMS (iTMS), we showed that these differences in I-wave characteristics influence the induction of cortical plasticity in older adults. ABSTRACT Previous research shows that neuroplasticity assessed using transcranial magnetic stimulation (TMS) is reduced in older adults. While this deficit is often assumed to represent altered synaptic modification processes, age-related changes in the interneuronal circuits activated by TMS may also contribute. Here we assessed age-related differences in the characteristics of the corticospinal indirect (I) waves and how they influence plasticity induction in primary motor cortex. Twenty young (23.7 ± 3.4 years) and 19 older adults (70.6 ± 6.0 years) participated in these studies. I-wave recruitment was assessed by changing the direction of the current used to activate the motor cortex, whereas short-interval intracortical facilitation (SICF) was recorded to assess facilitatory I-wave interactions. In a separate study, I-wave periodicity TMS (iTMS) was used to examine the effect of I-wave latency on motor cortex plasticity. Data from the motor-evoked potential (MEP) onset latency produced using different coil orientations suggested that there were no age-related differences in preferential I-wave recruitment (P = 0.6). However, older adults demonstrated significant reductions in MEP facilitation at all 3 SICF peaks (all P values < 0.05) and a delayed latency of the second and third SICF peaks (all P values < 0.05). Using I-wave intervals that were optimal for young and older adults, these changes in the late I-waves were shown to influence the plasticity response in older adults after iTMS. These findings suggest that temporal characteristics are delayed for the late I-waves in older adults, and that optimising TMS interventions based on I-wave characteristics may improve the plasticity response in older adults.
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Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - John Cirillo
- Movement Neuroscience Laboratory, Department of Exercise Sciences, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
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Transcranial magnetic stimulation modulation of corticospinal excitability by targeting cortical I-waves with biphasic paired-pulses. Brain Stimul 2018; 11:322-326. [DOI: 10.1016/j.brs.2017.10.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/03/2017] [Accepted: 10/16/2017] [Indexed: 11/21/2022] Open
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Huang YZ, Lu MK, Antal A, Classen J, Nitsche M, Ziemann U, Ridding M, Hamada M, Ugawa Y, Jaberzadeh S, Suppa A, Paulus W, Rothwell J. Plasticity induced by non-invasive transcranial brain stimulation: A position paper. Clin Neurophysiol 2017; 128:2318-2329. [DOI: 10.1016/j.clinph.2017.09.007] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 08/31/2017] [Accepted: 09/05/2017] [Indexed: 12/11/2022]
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Raco V, Bauer R, Norim S, Gharabaghi A. Cumulative effects of single TMS pulses during beta-tACS are stimulation intensity-dependent. Brain Stimul 2017; 10:1055-1060. [DOI: 10.1016/j.brs.2017.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/24/2017] [Accepted: 07/25/2017] [Indexed: 11/25/2022] Open
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Munoz-Rubke F, Mirdamadi JL, Lynch AK, Block HJ. Modality-specific Changes in Motor Cortex Excitability After Visuo-proprioceptive Realignment. J Cogn Neurosci 2017; 29:2054-2067. [PMID: 28777059 DOI: 10.1162/jocn_a_01171] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Spatial realignment of visual and proprioceptive estimates of hand position is necessary both to keep the estimates in register over time and to compensate for sensory perturbations. Such realignment affects perceived hand position, which the brain must use to plan hand movements. We would therefore expect visuo-proprioceptive realignment to affect the motor system at some level, but the physiological basis of this interaction is unknown. Here, we asked whether activity in primary motor cortex (M1), a well-known substrate of motor control, shows evidence of change after visuo-proprioceptive realignment. In two sessions each, 32 healthy adults experienced spatially misaligned or veridical visual and proprioceptive information about their static left index finger. Participants indicated perceived finger position with no performance feedback or knowledge of results. Using TMS over the M1 representation of the misaligned finger, we found no average difference between sessions. However, regression analysis indicated that, in the misaligned session only, proprioceptive realignment was linked with a decrease in M1 activity and visual realignment was linked with an increase in M1 activity. Proprioceptive and visual realignment were inversely related to each other. These results suggest that visuo-proprioceptive realignment does indeed have a physiological impact on the motor system. The lack of a between-session mean difference in M1 activity suggests that the basis of the effect is not the multisensory realignment computation itself, independent of modality. Rather, the changes in M1 are consistent with a modality-specific neural mechanism, such as modulation of somatosensory cortex or dorsal stream visual areas that impact M1.
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Di Lazzaro V, Rothwell J, Capogna M. Noninvasive Stimulation of the Human Brain: Activation of Multiple Cortical Circuits. Neuroscientist 2017; 24:246-260. [DOI: 10.1177/1073858417717660] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Noninvasive brain stimulation methods, such as transcranial electric stimulation and transcranial magnetic stimulation are widely used tools for both basic research and clinical applications. However, the cortical circuits underlying their effects are poorly defined. Here we review the current knowledge based on data mostly coming from experiments performed on human subjects, and also to a lesser extent on rodent or primate models. The data suggest that multiple mechanisms are likely to be involved, such as the direct activation of layer V pyramidal neurons, but also of different types of GABAergic interneurons. In this regard, we propose a key role for a specific type of interneuron known as neurogliaform cell.
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Affiliation(s)
- Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
- Fondazione Alberto Sordi–Research Institute for Ageing, Rome, Italy
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK
| | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- The Danish Research Institute of Translational Neuroscience–DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Gray WA, Palmer JA, Wolf SL, Borich MR. Abnormal EEG Responses to TMS During the Cortical Silent Period Are Associated With Hand Function in Chronic Stroke. Neurorehabil Neural Repair 2017; 31:666-676. [PMID: 28604171 DOI: 10.1177/1545968317712470] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Abnormal brain excitability influences recovery after stroke at which time a prolonged transcranial magnetic stimulation (TMS)-induced electromyographic silent period is thought to reflect abnormal inhibitory interneuron excitability. Cortical excitability can be probed directly during the silent period using concurrent electroencephalography (EEG) of TMS-evoked responses. OBJECTIVE The primary study objectives were to characterize TMS-evoked cortical potentials (TEPs) using EEG and to investigate associations with persistent hand and arm motor dysfunction in individuals with chronic stroke. METHODS Thirteen participants with chronic stroke-related mild-moderate arm motor impairment and 12 matched controls completed a single TMS-EEG cortical excitability assessment. TEPs recorded from the vertex during cortical silent period (CSP) assessment and while at rest were used to evaluate differences in cortical excitability between stroke and control participants. Associations between TEPs and CSP duration with measures of upper extremity motor behavior were investigated. RESULTS Significantly increased TEP component peak amplitudes and delayed latencies were observed for stroke participants compared with controls during CSP assessment and while at rest. Delayed early TEP component (P30) peak latencies during CSP assessment were associated with less manual dexterity. CSP duration was prolonged in stroke participants, and correlated with P30 peak latency and paretic arm dysfunction. CONCLUSIONS Abnormal cortical excitability directly measured by early TMS-evoked EEG responses during CSP assessment suggests abnormal cortical inhibition is associated with hand dysfunction in chronic stroke. Further investigation of abnormal cortical inhibition in specific brain networks is necessary to characterize the salient neurophysiologic mechanisms contributing to persistent motor dysfunction after stroke.
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Affiliation(s)
- Whitney A Gray
- 1 Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Jacqueline A Palmer
- 1 Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Steven L Wolf
- 1 Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA, USA.,2 Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur, GA, USA
| | - Michael R Borich
- 1 Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA, USA
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Neva JL, Brown KE, Mang CS, Francisco BA, Boyd LA. An acute bout of exercise modulates both intracortical and interhemispheric excitability. Eur J Neurosci 2017; 45:1343-1355. [PMID: 28370664 DOI: 10.1111/ejn.13569] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 11/28/2022]
Abstract
Primary motor cortex (M1) excitability is modulated following a single session of cycling exercise. Specifically, short-interval intracortical inhibition and intracortical facilitation are altered following a session of cycling, suggesting that exercise affects the excitability of varied cortical circuits. Yet we do not know whether a session of exercise also impacts the excitability of interhemispheric circuits between, and other intracortical circuits within, M1. Here we present two experiments designed to address this gap in knowledge. In experiment 1, single and paired pulse transcranial magnetic stimulation (TMS) were used to measure intracortical circuits including, short-interval intracortical facilitation (SICF) tested at 1.1, 1.5, 2.7, 3.1 and 4.5 ms interstimulus intervals (ISIs), contralateral silent period (CSP) and interhemispheric interactions by measuring transcallosal inhibition (TCI) recorded from the abductor pollicus brevis muscles. All circuits were assessed bilaterally pre and two time points post (immediately, 30 min) moderate intensity lower limb cycling. SICF was enhanced in the left hemisphere after exercise at the 1.5 ms ISI. Also, CSP was shortened and TCI decreased bilaterally after exercise. In Experiment 2, corticospinal and spinal excitability were tested before and after exercise to investigate the locus of the effects found in Experiment 1. Exercise did not impact motor-evoked potential recruitment curves, Hoffman reflex or V-wave amplitudes. These results suggest that a session of exercise decreases intracortical and interhemispheric inhibition and increases facilitation in multiple circuits within M1, without concurrently altering spinal excitability. These findings have implications for developing exercise strategies designed to potentiate M1 plasticity and skill learning in healthy and clinical populations.
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Affiliation(s)
- J L Neva
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - K E Brown
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - C S Mang
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - B A Francisco
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - L A Boyd
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
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Petrichella S, Johnson N, He B. The influence of corticospinal activity on TMS-evoked activity and connectivity in healthy subjects: A TMS-EEG study. PLoS One 2017; 12:e0174879. [PMID: 28384197 PMCID: PMC5383066 DOI: 10.1371/journal.pone.0174879] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/16/2017] [Indexed: 11/30/2022] Open
Abstract
Combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) can be used to analyze cortical reactivity and connectivity. However, the effects of corticospinal and peripheral muscle activity on TMS-evoked potentials (TEPs) are not well understood. The aim of this paper is to evaluate the relationship between cortico-spinal activity, in the form of peripheral motor-evoked potentials (MEPs), and the TEPs from motor areas, along with the connectivity among activated brain areas. TMS was applied to left and right motor cortex (M1), separately, at motor threshold while multi-channel EEG responses were recorded in 17 healthy human subjects. Cortical excitability and source imaging analysis were performed for all trials at each stimulation location, as well as comparing trials resulting in MEPs to those without. Connectivity analysis was also performed comparing trials resulting in MEPs to those without. Cortical excitability results significantly differed between the MEP and no-MEP conditions for left M1 TMS at 60 ms (CP1, CP3, C1) and for right M1 TMS at 54 ms (CP6, C6). Connectivity analysis revealed higher outflow and inflow between M1 and somatosensory cortex bi-directionally for trials with MEPs than those without for both left M1 TMS (at 60, 100, 164 ms) and right M1 TMS (at 54, 100, and 164 ms). Both TEP amplitudes and connectivity measures related to motor and somatosensory areas ipsilateral to the stimulation were shown to correspond with peripheral MEP amplitudes. This suggests that cortico-spinal activation, along with the resulting somatosensory feedback, affects the cortical activity and dynamics within motor areas reflected in the TEPs. The findings suggest that TMS-EEG, along with adaptive connectivity estimators, can be used to evaluate the cortical dynamics associated with sensorimotor integration and proprioceptive manipulation along with the influence of peripheral muscle feedback.
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Affiliation(s)
- Sara Petrichella
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Computer Science and Computer Engineering, University Campus Bio-Medico, Rome, Italy
| | - Nessa Johnson
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Bin He
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
- Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
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