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Jiao X, Hu Q, Tang Y, Zhang T, Zhang J, Wang X, Sun J, Wang J. Abnormal Global Cortical Responses in Drug-Naïve Patients With Schizophrenia Following Orbitofrontal Cortex Stimulation: A Concurrent Transcranial Magnetic Stimulation-Electroencephalography Study. Biol Psychiatry 2024; 96:342-351. [PMID: 38852897 DOI: 10.1016/j.biopsych.2024.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 05/16/2024] [Accepted: 05/31/2024] [Indexed: 06/11/2024]
Abstract
BACKGROUND Abnormalities in cortical excitability and plasticity have been considered to underlie the pathophysiology of schizophrenia. Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) can provide a direct evaluation of cortical responses to TMS. Here, we employed TMS-EEG to investigate cortical responses to orbitofrontal cortex (OFC) stimulation in schizophrenia. METHODS In total, we recruited 92 drug-naïve patients with first-episode schizophrenia and 51 age- and sex-matched healthy individuals. For each participant, one session of 1-Hz repetitive TMS (rTMS) was delivered to the right OFC, and TMS-EEG data were obtained to explore the change in cortical-evoked activities before and immediately after rTMS during the eyes-closed state. The MATRICS Consensus Cognitive Battery was used to assess neurocognitive performance. RESULTS The cortical responses indexed by global mean field amplitudes (i.e., P30, N45, and P60) were larger in patients with schizophrenia than in healthy control participants at baseline. Furthermore, after one session of 1-Hz rTMS over the right OFC, the N100 amplitude was significantly reduced in the healthy control group but not in the schizophrenia group. In the healthy control participants, there was a significant correlation between modulation of P60 amplitude by rTMS and working memory; however, this correlation was absent in patients with schizophrenia. CONCLUSIONS Aberrant global cortical responses following right OFC stimulation were found in patients with drug-naïve first-episode schizophrenia, supporting its significance in the primary pathophysiology of schizophrenia.
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Affiliation(s)
- Xiong Jiao
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Med.-X Engineering Research Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Qiang Hu
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Psychiatry, Zhenjiang Mental Health Center, Jiangsu, China
| | - Yingying Tang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Brain Science and Technology Research Center, Shanghai Jiao Tong University, Shanghai, China
| | - Tianhong Zhang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jie Zhang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Med.-X Engineering Research Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Xijin Wang
- The First Psychiatric Hospital of Harbin, Harbin, Heilongjiang Province, China
| | - Junfeng Sun
- Shanghai Med.-X Engineering Research Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China; Brain Science and Technology Research Center, Shanghai Jiao Tong University, Shanghai, China.
| | - Jijun Wang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; CAS Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Chinese Academy of Sciences, Shanghai, China; Institute of Psychology and Behavioral Science, Shanghai Jiao Tong University, Shanghai, China.
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Speranza BE, Hill AT, Do M, Cerins A, Donaldson PH, Desarkar P, Oberman LM, Das S, Enticott PG, Kirkovski M. The Neurophysiological Effects of Theta Burst Stimulation as Measured by Electroencephalography: A Systematic Review. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2024:S2451-9022(24)00206-4. [PMID: 39084526 DOI: 10.1016/j.bpsc.2024.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/10/2024] [Accepted: 07/21/2024] [Indexed: 08/02/2024]
Abstract
Theta burst stimulation (TBS) is a non-invasive brain stimulation technique that can modulate neural activity. The effect of TBS on regions beyond the motor cortex remains unclear. With increased interest in applying TBS to non-motor regions for research and clinical purposes, these effects must be understood and characterised. We synthesised the electrophysiological effects of a single session of TBS, as indexed by electroencephalography (EEG) and concurrent transcranial magnetic stimulation and EEG (TMS-EEG), in non-clinical participants. We reviewed 79 studies that administered either continuous TBS (cTBS) or intermittent TBS (iTBS) protocols. Broadly, cTBS suppressed and iTBS facilitated evoked response component amplitudes. Response to TBS as measured by spectral power and connectivity was much more variable. Variability increased in the presence of task stimuli. There was a large degree of heterogeneity in the research methodology across studies. Additionally, the effect of individual differences on TBS response is insufficiently investigated. Future research investigating the effects of TBS as measured by EEG must consider methodological and individual factors that may affect TBS outcomes.
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Affiliation(s)
- Bridgette E Speranza
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia.
| | - Aron T Hill
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia
| | - Michael Do
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia
| | - Andris Cerins
- Brain Stimulation Lab, Alfred Psychiatry Research Centre, Department of Psychiatry, School of Translational Medicine, Monash University, Melbourne, Australia; Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia
| | - Peter H Donaldson
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia
| | - Pushpal Desarkar
- Centre for Addiction and Mental Health, Toronto, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Lindsay M Oberman
- Noninvasive Neuromodulation Unit, Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Sushmit Das
- Centre for Addiction and Mental Health, Toronto, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia
| | - Melissa Kirkovski
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia; Institute for Health and Sport, Victoria University, Melbourne, Australia
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Mijancos-Martínez G, Bachiller A, Fernández-Linsenbarth I, Romero S, Serna LY, Molina V, Mañanas MÁ. Individualized time windows enhance TMS-EEG signal characterization and improve assessment of cortical function in schizophrenia. Eur Arch Psychiatry Clin Neurosci 2024:10.1007/s00406-024-01859-z. [PMID: 38969752 DOI: 10.1007/s00406-024-01859-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 06/20/2024] [Indexed: 07/07/2024]
Abstract
Transcranial magnetic stimulation and electroencephalography (TMS-EEG) recordings are crucial to directly assess cortical excitability and inhibition in a non-invasive and task-free manner. TMS-EEG signals are characterized by TMS-evoked potentials (TEPs), which are employed to evaluate cortical function. Nonetheless, different time windows (TW) have been used to compute them over the years. Moreover, these TWs tend to be the same for all participants omitting the intersubject variability. Therefore, the objective of this study is to assess the effect of using different TWs to compute the TEPs, moving from a common fixed TW to more adaptive individualized TWs. Twenty-nine healthy (HC) controls and twenty schizophrenia patients (SCZ) underwent single-pulse (SP) TMS-EEG protocol. Firstly, only the HC were considered to evaluate the TEPs for three different TWs in terms of amplitude and topographical distribution. Secondly, the SCZ patients were included to determine which TW is better to characterize the brain alterations of SCZ. The results indicate that a more individualized TW provides a better characterization of the SP TMS-EEG signals, although all of them show the same tendency. Regarding the comparison between groups, the individualized TW is the one that provides a better differentiation between populations. They also provide further support to the possible imbalance of cortical excitability/inhibition in the SCZ population due to its reduced activity in the N45 TEP and greater amplitude values in the N100. Results also suggest that the SCZ brain has a baseline hyperactive state since the TEPs of the SCZ appear earlier than those of the HC.
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Affiliation(s)
- Gema Mijancos-Martínez
- Biomedical Engineering Research Centre (CREB), Department of Automatic Control (ESAII), Universitat Politècnica de Catalunya - BarcelonaTech (UPC), Barcelona, Spain.
- Institute of Research Sant Joan de Déu, Barcelona, Spain.
| | - Alejandro Bachiller
- Biomedical Engineering Research Centre (CREB), Department of Automatic Control (ESAII), Universitat Politècnica de Catalunya - BarcelonaTech (UPC), Barcelona, Spain
- Institute of Research Sant Joan de Déu, Barcelona, Spain
| | | | - Sergio Romero
- Biomedical Engineering Research Centre (CREB), Department of Automatic Control (ESAII), Universitat Politècnica de Catalunya - BarcelonaTech (UPC), Barcelona, Spain
- Institute of Research Sant Joan de Déu, Barcelona, Spain
- CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Leidy Y Serna
- Biomedical Engineering Research Centre (CREB), Department of Automatic Control (ESAII), Universitat Politècnica de Catalunya - BarcelonaTech (UPC), Barcelona, Spain
- CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Vicente Molina
- Psychiatry Department, School of Medicine, University of Valladolid, Valladolid, Spain
- Psychiatry Service, Clinical Hospital of Valladolid, Valladolid, Spain
- Neurosciences Institute of Castilla y Léon (INCYL), University of Salamanca, Salamanca, Spain
| | - Miguel Ángel Mañanas
- Biomedical Engineering Research Centre (CREB), Department of Automatic Control (ESAII), Universitat Politècnica de Catalunya - BarcelonaTech (UPC), Barcelona, Spain
- Institute of Research Sant Joan de Déu, Barcelona, Spain
- CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
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Murphy DLK, Koponen LM, Wood E, Li Y, Bukhari-Parlakturk N, Goetz SM, Peterchev AV. Reduced Auditory Perception and Brain Response with Quiet TMS Coil. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600400. [PMID: 39005397 PMCID: PMC11244855 DOI: 10.1101/2024.06.24.600400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
BACKGROUND Electromagnetic forces in transcranial magnetic stimulation (TMS) coils generate a loud clicking sound that produces confounding auditory activation and is potentially hazardous to hearing. To reduce this noise while maintaining stimulation efficiency similar to conventional TMS coils, we previously developed a quiet TMS double containment coil (qTMS-DCC). OBJECTIVE To compare the stimulation strength, perceived loudness, and EEG response between qTMS-DCC and a commercial TMS coil. METHODS Nine healthy volunteers participated in a within-subject study design. The resting motor thresholds (RMTs) for qTMS-DCC and MagVenture Cool-B65 were measured. Psychoacoustic titration matched the Cool-B65 loudness to qTMS-DCC pulsed at 80, 100, and 120% RMT. Event-related potentials (ERPs) were recorded for both coils. The psychoacoustic titration and ERPs were acquired with the coils both on and 6 cm off the scalp, the latter isolating the effects of airborne auditory stimulation from body sound and electromagnetic stimulation. The ERP comparisons focused on a centro-frontal region that encompassed peak responses in the global signal. RESULTS RMT did not differ significantly between the coils, with or without the EEG cap on the head. qTMS-DCC was perceived to be substantially quieter than Cool-B65. For example, qTMS-DCC at 100% coil-specific RMT sounded like Cool-B65 at 34% RMT. The general ERP waveform and topography were similar between the two coils, as were early-latency components, indicating comparable electromagnetic brain stimulation in the on-scalp condition. qTMS-DCC had a significantly smaller P180 component in both on-scalp and off-scalp conditions, supporting reduced auditory activation. CONCLUSIONS The stimulation efficiency of qTMS-DCC matched Cool-B65, while having substantially lower perceived loudness and auditory-evoked potentials. Highlights qTMS coil is subjectively and objectively quieter than conventional Cool-B65 coilqTMS coil at 100% motor threshold was as loud as Cool-B65 at 34% motor thresholdAttenuated coil noise reduced auditory N100 and P180 evoked response componentsqTMS coil enables reduction of auditory activation without masking.
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Beck MM, Christiansen L, Madsen MAJ, Jadidi AF, Vinding MC, Thielscher A, Bergmann TO, Siebner HR, Tomasevic L. Transcranial magnetic stimulation of primary motor cortex elicits an immediate transcranial evoked potential. Brain Stimul 2024; 17:802-812. [PMID: 38909748 DOI: 10.1016/j.brs.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 06/10/2024] [Accepted: 06/17/2024] [Indexed: 06/25/2024] Open
Abstract
BACKGROUND Transcranial evoked potentials (TEPs) measured via electroencephalography (EEG) are widely used to study the cortical responses to transcranial magnetic stimulation (TMS). Immediate transcranial evoked potentials (i-TEPs) have been obscured by pulse and muscular artifacts. Thus, the TEP peaks that are commonly reported have latencies that are too long to be caused by direct excitation of cortical neurons. METHODS In 25 healthy individuals, we recorded i-TEPs evoked by a single biphasic TMS pulse targeting the primary motor hand area (M1HAND) or parietal or midline control sites. Sampling EEG at 50 kHz enabled us to reduce the duration of the TMS pulse artifact to a few milliseconds, while minor adjustments of the TMS coil tilt or position enabled us to avoid cranial muscular twitches during the experiment. RESULTS We observed an early positive EEG deflection starting after approx. 2 ms followed by a series of superimposed peaks with an inter-peak interval of ∼1.1-1.4 ms in multiple electrodes surrounding the stimulated sensorimotor region. This multi-peak i-TEP response was only evoked by TMS of the M1HAND region and was modified by changes in stimulation intensity and current direction. DISCUSSION Single-pulse TMS of the M1HAND evokes an immediate local multi-peak response at the cortical site of stimulation. Our results suggest that the observed i-TEP patterns are genuine cortical responses evoked by TMS caused by synchronized excitation of pyramidal neurons in the targeted precentral cortex. This notion needs to be corroborated in future studies, including further investigations into the potential contribution of instrumental or physiological artifacts.
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Affiliation(s)
- Mikkel Malling Beck
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Lasse Christiansen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark; Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Mads Alexander Just Madsen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Armita Faghani Jadidi
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Mikkel Christoffer Vinding
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Axel Thielscher
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark; Department of Health Technology, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Til Ole Bergmann
- Neuroimaging Center (NIC), Johannes Gutenberg University Medical Center, Mainz, Germany; Leibniz Institute for Resilience Research, Mainz, Germany
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg and Frederiksberg, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Leo Tomasevic
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.
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Segning CM, da Silva RA, Ngomo S. An Innovative EEG-Based Pain Identification and Quantification: A Pilot Study. SENSORS (BASEL, SWITZERLAND) 2024; 24:3873. [PMID: 38931657 PMCID: PMC11207749 DOI: 10.3390/s24123873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024]
Abstract
OBJECTIVE The present pilot study aimed to propose an innovative scale-independent measure based on electroencephalographic (EEG) signals for the identification and quantification of the magnitude of chronic pain. METHODS EEG data were collected from three groups of participants at rest: seven healthy participants with pain, 15 healthy participants submitted to thermal pain, and 66 participants living with chronic pain. Every 30 s, the pain intensity score felt by the participant was also recorded. Electrodes positioned in the contralateral motor region were of interest. After EEG preprocessing, a complex analytical signal was obtained using Hilbert transform, and the upper envelope of the EEG signal was extracted. The average coefficient of variation of the upper envelope of the signal was then calculated for the beta (13-30 Hz) band and proposed as a new EEG-based indicator, namely Piqβ, to identify and quantify pain. MAIN RESULTS The main results are as follows: (1) A Piqβ threshold at 10%, that is, Piqβ ≥ 10%, indicates the presence of pain, and (2) the higher the Piqβ (%), the higher the extent of pain. CONCLUSIONS This finding indicates that Piqβ can objectively identify and quantify pain in a population living with chronic pain. This new EEG-based indicator can be used for objective pain assessment based on the neurophysiological body response to pain. SIGNIFICANCE Objective pain assessment is a valuable decision-making aid and an important contribution to pain management and monitoring.
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Affiliation(s)
- Colince Meli Segning
- Department of Applied Sciences, UQAC (Université du Québec à Chicoutimi), Chicoutimi, QC G7H 2B1, Canada;
- Biomechanical and Neurophysiological Research Laboratory in Neuro-Musculoskeletal Rehabilitation (Lab BioNR), Department of Health Sciences, UQAC (Université du Québec à Chicoutimi), Chicoutimi, QC G7H 2B1, Canada;
| | - Rubens A. da Silva
- Biomechanical and Neurophysiological Research Laboratory in Neuro-Musculoskeletal Rehabilitation (Lab BioNR), Department of Health Sciences, UQAC (Université du Québec à Chicoutimi), Chicoutimi, QC G7H 2B1, Canada;
- Centre Intégré de Santé et Services Sociaux du Saguenay-Lac-Saint-Jean (CIUSSS SLSJ), Specialized Geriatrics Rehabilitation Services at the La Baie Hospital, CIUSSS-SLSJ, Saguenay, QC G7H 7K9, Canada
| | - Suzy Ngomo
- Biomechanical and Neurophysiological Research Laboratory in Neuro-Musculoskeletal Rehabilitation (Lab BioNR), Department of Health Sciences, UQAC (Université du Québec à Chicoutimi), Chicoutimi, QC G7H 2B1, Canada;
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Solomon EA, Wang JB, Oya H, Howard MA, Trapp NT, Uitermarkt BD, Boes AD, Keller CJ. TMS provokes target-dependent intracranial rhythms across human cortical and subcortical sites. Brain Stimul 2024; 17:698-712. [PMID: 38821396 PMCID: PMC11313454 DOI: 10.1016/j.brs.2024.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 05/25/2024] [Accepted: 05/26/2024] [Indexed: 06/02/2024] Open
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) is believed to alter ongoing neural activity and cause circuit-level changes in brain function. While the electrophysiological effects of TMS have been extensively studied with scalp electroencephalography (EEG), this approach generally evaluates low-frequency neural activity at the cortical surface. However, TMS can be safely used in patients with intracranial electrodes (iEEG), allowing for direct assessment of deeper and more localized oscillatory responses across the frequency spectrum. OBJECTIVE/HYPOTHESIS Our study used iEEG to understand the effects of TMS on human neural activity in the spectral domain. We asked (1) which brain regions respond to cortically-targeted TMS, and in what frequency bands, (2) whether deeper brain structures exhibit oscillatory responses, and (3) whether the neural responses to TMS reflect evoked versus induced oscillations. METHODS We recruited 17 neurosurgical patients with indwelling electrodes and recorded neural activity while patients underwent repeated trials of single-pulse TMS at either the dorsolateral prefrontal cortex (DLPFC) or parietal cortex. iEEG signals were analyzed using spectral methods to understand the oscillatory responses to TMS. RESULTS Stimulation to DLPFC drove widespread low-frequency increases (3-8 Hz) in frontolimbic cortices and high-frequency decreases (30-110 Hz) in frontotemporal areas, including the hippocampus. Stimulation to parietal cortex specifically provoked low-frequency responses in the medial temporal lobe. While most low-frequency activity was consistent with phase-locked evoked responses, anterior frontal regions exhibited induced theta oscillations following DLPFC stimulation. CONCLUSIONS By combining TMS with intracranial EEG recordings, our results suggest that TMS is an effective means to perturb oscillatory neural activity in brain-wide networks, including deeper structures not directly accessed by stimulation itself.
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Affiliation(s)
- Ethan A Solomon
- Dept. of Psychiatry and Behavioral Sciences, Stanford University Medical Center, Palo Alto, 94305, CA, USA; Wu Tsai Neurosciences Institute, Stanford University, Stanford, 94305, CA, USA.
| | - Jeffrey B Wang
- Dept. of Psychiatry and Behavioral Sciences, Stanford University Medical Center, Palo Alto, 94305, CA, USA; Biophysics Graduate Program, Stanford University Medical Center, Stanford, 94305, CA, USA
| | - Hiroyuki Oya
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA
| | - Matthew A Howard
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA
| | - Nicholas T Trapp
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA; Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA
| | - Brandt D Uitermarkt
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA
| | - Aaron D Boes
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA; Department of Psychiatry, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA; Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, 52242, IA, USA
| | - Corey J Keller
- Dept. of Psychiatry and Behavioral Sciences, Stanford University Medical Center, Palo Alto, 94305, CA, USA; Veterans Affairs Palo Alto Healthcare System, and the Sierra Pacific Mental Illness, Research, Education, and Clinical Center (MIRECC), Palo Alto, 94305, CA, USA; Wu Tsai Neurosciences Institute, Stanford University, Stanford, 94305, CA, USA
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She X, Nix KC, Cline CC, Qi W, Tugin S, He Z, Baumer FM. Stability of transcranial magnetic stimulation electroencephalogram evoked potentials in pediatric epilepsy. Sci Rep 2024; 14:9045. [PMID: 38641629 PMCID: PMC11031596 DOI: 10.1038/s41598-024-59468-8] [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: 12/11/2023] [Accepted: 04/11/2024] [Indexed: 04/21/2024] Open
Abstract
Transcranial magnetic stimulation paired with electroencephalography (TMS-EEG) can measure local excitability and functional connectivity. To address trial-to-trial variability, responses to multiple TMS pulses are recorded to obtain an average TMS evoked potential (TEP). Balancing adequate data acquisition to establish stable TEPs with feasible experimental duration is critical when applying TMS-EEG to clinical populations. Here we aim to investigate the minimum number of pulses (MNP) required to achieve stable TEPs in children with epilepsy. Eighteen children with Self-Limited Epilepsy with Centrotemporal Spikes, a common epilepsy arising from the motor cortices, underwent multiple 100-pulse blocks of TMS to both motor cortices over two days. TMS was applied at 120% of resting motor threshold (rMT) up to a maximum of 100% maximum stimulator output. The average of all 100 pulses was used as a "gold-standard" TEP to which we compared "candidate" TEPs obtained by averaging subsets of pulses. We defined TEP stability as the MNP needed to achieve a concordance correlation coefficient of 80% between the candidate and "gold-standard" TEP. We additionally assessed whether experimental or clinical factors affected TEP stability. Results show that stable TEPs can be derived from fewer than 100 pulses, a number typically used for designing TMS-EEG experiments. The early segment (15-80 ms) of the TEP was less stable than the later segment (80-350 ms). Global mean field amplitude derived from all channels was less stable than local TEP derived from channels overlying the stimulated site. TEP stability did not differ depending on stimulated hemisphere, block order, or antiseizure medication use, but was greater in older children. Stimulation administered with an intensity above the rMT yielded more stable local TEPs. Studies of TMS-EEG in pediatrics have been limited by the complexity of experimental set-up and time course. This study serves as a critical starting point, demonstrating the feasibility of designing efficient TMS-EEG studies that use a relatively small number of pulses to study pediatric epilepsy and potentially other pediatric groups.
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Affiliation(s)
- Xiwei She
- Department of Neurology, Stanford University, Stanford, CA, USA
| | - Kerry C Nix
- Department of Neurology, Stanford University, Stanford, CA, USA
| | - Christopher C Cline
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Wendy Qi
- Department of Neurology, Stanford University, Stanford, CA, USA
| | - Sergei Tugin
- Department of Neurology, Stanford University, Stanford, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Zihuai He
- Department of Neurology, Stanford University, Stanford, CA, USA
| | - Fiona M Baumer
- Department of Neurology, Stanford University, Stanford, CA, USA.
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Farzan F. Transcranial Magnetic Stimulation-Electroencephalography for Biomarker Discovery in Psychiatry. Biol Psychiatry 2024; 95:564-580. [PMID: 38142721 DOI: 10.1016/j.biopsych.2023.12.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 12/08/2023] [Accepted: 12/15/2023] [Indexed: 12/26/2023]
Abstract
Current diagnosis and treatment of psychiatric illnesses are still based on behavioral observations and self-reports, commonly leading to prolonged untreated illness. Biological markers (biomarkers) may offer an opportunity to revolutionize clinical psychiatry practice by helping provide faster and potentially more effective therapies. Transcranial magnetic stimulation concurrent with electroencephalography (TMS-EEG) is a noninvasive brain mapping methodology that can assess the functions and dynamics of specific brain circuitries in awake humans and aid in biomarker discovery. This article provides an overview of TMS-EEG-based biomarkers that may hold potential in psychiatry. The methodological readiness of the TMS-EEG approach and steps in the validation of TMS-EEG biomarkers for clinical utility are discussed. Biomarker discovery with TMS-EEG is in the early stages, and several validation steps are still required before clinical implementations are realized. Thus far, TMS-EEG predictors of response to magnetic brain stimulation treatments in particular have shown promise for translation to clinical practice. Larger-scale studies can confirm validation followed by biomarker-informed trials to assess added value compared to existing practice.
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Affiliation(s)
- Faranak Farzan
- eBrain Lab, School of Mechatronic Systems Engineering, Simon Fraser University, Surrey, British Columbia, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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10
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Song Y, Gordon PC, Metsomaa J, Rostami M, Belardinelli P, Ziemann U. Evoked EEG Responses to TMS Targeting Regions Outside the Primary Motor Cortex and Their Test-Retest Reliability. Brain Topogr 2024; 37:19-36. [PMID: 37996562 PMCID: PMC10771591 DOI: 10.1007/s10548-023-01018-y] [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: 06/16/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023]
Abstract
Transcranial magnetic stimulation (TMS)-evoked electroencephalography (EEG) potentials (TEPs) provide unique insights into cortical excitability and connectivity. However, confounding EEG signals from auditory and somatosensory co-stimulation complicate TEP interpretation. Our optimized sham procedure established with TMS of primary motor cortex (Gordon in JAMA 245:118708, 2021) differentiates direct cortical EEG responses to TMS from those caused by peripheral sensory inputs. Using this approach, this study aimed to investigate TEPs and their test-retest reliability when targeting regions outside the primary motor cortex, specifically the left angular gyrus, supplementary motor area, and medial prefrontal cortex. We conducted three identical TMS-EEG sessions one week apart involving 24 healthy participants. In each session, we targeted the three areas separately using a figure-of-eight TMS coil for active TMS, while a second coil away from the head produced auditory input for sham TMS. Masking noise and electric scalp stimulation were applied in both conditions to achieve matched EEG responses to peripheral sensory inputs. High test-retest reliability was observed in both conditions. However, reliability declined for the 'cleaned' TEPs, resulting from the subtraction of evoked EEG response to the sham TMS from those to the active, particularly for latencies > 100 ms following the TMS pulse. Significant EEG differences were found between active and sham TMS at latencies < 90 ms for all targeted areas, exhibiting distinct spatiotemporal characteristics specific to each target. In conclusion, our optimized sham procedure effectively reveals EEG responses to direct cortical activation by TMS in brain areas outside primary motor cortex. Moreover, we demonstrate the impact of peripheral sensory inputs on test-retest reliability of TMS-EEG responses.
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Affiliation(s)
- Yufei Song
- Department of Neurology and Stroke, University of Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Pedro C Gordon
- Department of Neurology and Stroke, University of Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Johanna Metsomaa
- Department of Neurology and Stroke, University of Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Maryam Rostami
- Faculty of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
| | - Paolo Belardinelli
- Department of Neurology and Stroke, University of Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Center for Mind/Brain Sciences, CIMeC, University of Trento, Trento, Italy
| | - Ulf Ziemann
- Department of Neurology and Stroke, University of Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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11
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Chowdhury NS, Chiang AKI, Millard SK, Skippen P, Chang WJ, Seminowicz DA, Schabrun SM. Combined transcranial magnetic stimulation and electroencephalography reveals alterations in cortical excitability during pain. eLife 2023; 12:RP88567. [PMID: 37966464 PMCID: PMC10651174 DOI: 10.7554/elife.88567] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) has been used to examine inhibitory and facilitatory circuits during experimental pain and in chronic pain populations. However, current applications of TMS to pain have been restricted to measurements of motor evoked potentials (MEPs) from peripheral muscles. Here, TMS was combined with electroencephalography (EEG) to determine whether experimental pain could induce alterations in cortical inhibitory/facilitatory activity observed in TMS-evoked potentials (TEPs). In Experiment 1 (n=29), multiple sustained thermal stimuli were administered to the forearm, with the first, second, and third block of thermal stimuli consisting of warm but non-painful (pre-pain block), painful (pain block) and warm but non-painful (post-pain block) temperatures, respectively. During each stimulus, TMS pulses were delivered while EEG (64 channels) was simultaneously recorded. Verbal pain ratings were collected between TMS pulses. Relative to pre-pain warm stimuli, painful stimuli led to an increase in the amplitude of the frontocentral negative peak ~45 ms post-TMS (N45), with a larger increase associated with higher pain ratings. Experiments 2 and 3 (n=10 in each) showed that the increase in the N45 in response to pain was not due to changes in sensory potentials associated with TMS, or a result of stronger reafferent muscle feedback during pain. This is the first study to use combined TMS-EEG to examine alterations in cortical excitability in response to pain. These results suggest that the N45 TEP peak, which indexes GABAergic neurotransmission, is implicated in pain perception and is a potential marker of individual differences in pain sensitivity.
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Affiliation(s)
- Nahian Shahmat Chowdhury
- Center for Pain IMPACT, Neuroscience Research AustraliaSydneyAustralia
- University of New South WalesSydneyAustralia
| | - Alan KI Chiang
- Center for Pain IMPACT, Neuroscience Research AustraliaSydneyAustralia
- University of New South WalesSydneyAustralia
| | - Samantha K Millard
- Center for Pain IMPACT, Neuroscience Research AustraliaSydneyAustralia
- University of New South WalesSydneyAustralia
| | - Patrick Skippen
- Center for Pain IMPACT, Neuroscience Research AustraliaSydneyAustralia
| | - Wei-Ju Chang
- Center for Pain IMPACT, Neuroscience Research AustraliaSydneyAustralia
- School of Health Sciences, College of Health, Medicine and Wellbeing, The University of NewcastleCallaghanAustralia
| | - David A Seminowicz
- Center for Pain IMPACT, Neuroscience Research AustraliaSydneyAustralia
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western OntarioLondonCanada
| | - Siobhan M Schabrun
- Center for Pain IMPACT, Neuroscience Research AustraliaSydneyAustralia
- The Gray Centre for Mobility and Activity, University of Western OntarioLondonCanada
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12
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Siviero I, Bonfanti D, Menegaz G, Savazzi S, Mazzi C, Storti SF. Graph Analysis of TMS-EEG Connectivity Reveals Hemispheric Differences following Occipital Stimulation. SENSORS (BASEL, SWITZERLAND) 2023; 23:8833. [PMID: 37960532 PMCID: PMC10650175 DOI: 10.3390/s23218833] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/23/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023]
Abstract
(1) Background: Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) provides a unique opportunity to investigate brain connectivity. However, possible hemispheric asymmetries in signal propagation dynamics following occipital TMS have not been investigated. (2) Methods: Eighteen healthy participants underwent occipital single-pulse TMS at two different EEG sites, corresponding to early visual areas. We used a state-of-the-art Bayesian estimation approach to accurately estimate TMS-evoked potentials (TEPs) from EEG data, which has not been previously used in this context. To capture the rapid dynamics of information flow patterns, we implemented a self-tuning optimized Kalman (STOK) filter in conjunction with the information partial directed coherence (iPDC) measure, enabling us to derive time-varying connectivity matrices. Subsequently, graph analysis was conducted to assess key network properties, providing insight into the overall network organization of the brain network. (3) Results: Our findings revealed distinct lateralized effects on effective brain connectivity and graph networks after TMS stimulation, with left stimulation facilitating enhanced communication between contralateral frontal regions and right stimulation promoting increased intra-hemispheric ipsilateral connectivity, as evidenced by statistical test (p < 0.001). (4) Conclusions: The identified hemispheric differences in terms of connectivity provide novel insights into brain networks involved in visual information processing, revealing the hemispheric specificity of neural responses to occipital stimulation.
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Affiliation(s)
- Ilaria Siviero
- Department of Computer Science, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy;
| | - Davide Bonfanti
- Perception and Awareness (PandA) Lab., Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Piazzale Ludovico Antonio Scuro 10, 37124 Verona, Italy; (D.B.); (S.S.); (C.M.)
| | - Gloria Menegaz
- Department of Engineering for Innovation Medicine, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy;
| | - Silvia Savazzi
- Perception and Awareness (PandA) Lab., Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Piazzale Ludovico Antonio Scuro 10, 37124 Verona, Italy; (D.B.); (S.S.); (C.M.)
| | - Chiara Mazzi
- Perception and Awareness (PandA) Lab., Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Piazzale Ludovico Antonio Scuro 10, 37124 Verona, Italy; (D.B.); (S.S.); (C.M.)
| | - Silvia Francesca Storti
- Department of Engineering for Innovation Medicine, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy;
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13
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Chowdhury NS, Chiang AKI, Millard SK, Skippen P, Chang WJ, Seminowicz DA, Schabrun SM. Alterations in cortical excitability during pain: A combined TMS-EEG Study. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.20.537735. [PMID: 37131586 PMCID: PMC10153239 DOI: 10.1101/2023.04.20.537735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Transcranial magnetic stimulation (TMS) has been used to examine inhibitory and facilitatory circuits during experimental pain and in chronic pain populations. However, current applications of TMS to pain have been restricted to measurements of motor evoked potentials (MEPs) from peripheral muscles. Here, TMS was combined with electroencephalography (EEG) to determine whether experimental pain could induce alterations in cortical inhibitory/facilitatory activity observed in TMS-evoked potentials (TEPs). In Experiment 1 (n = 29), multiple sustained thermal stimuli were administered to the forearm, with the first, second and third block of thermal stimuli consisting of warm but non-painful (pre-pain block), painful (pain block) and warm but non-painful (post-pain block) temperatures respectively. During each stimulus, TMS pulses were delivered while EEG (64 channels) was simultaneously recorded. Verbal pain ratings were collected between TMS pulses. Relative to pre-pain warm stimuli, painful stimuli led to an increase in the amplitude of the frontocentral negative peak ~45ms post-TMS (N45), with a larger increase associated with higher pain ratings. Experiments 2 and 3 (n = 10 in each) showed that the increase in the N45 in response to pain was not due to changes in sensory potentials associated with TMS, or a result of stronger reafferent muscle feedback during pain. This is the first study to use combined TMS-EEG to examine alterations in cortical excitability in response to pain. These results suggest that the N45 TEP peak, which indexes GABAergic neurotransmission, is implicated in pain perception and is a potential marker of individual differences in pain sensitivity.
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Affiliation(s)
- Nahian S Chowdhury
- Center for Pain IMPACT, Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia
| | - Alan KI Chiang
- Center for Pain IMPACT, Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia
| | - Samantha K Millard
- Center for Pain IMPACT, Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia
| | - Patrick Skippen
- Center for Pain IMPACT, Neuroscience Research Australia, Sydney, New South Wales, Australia
| | - Wei-Ju Chang
- Center for Pain IMPACT, Neuroscience Research Australia, Sydney, New South Wales, Australia
- School of Health Sciences, College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales, Australia
| | - David A Seminowicz
- Center for Pain IMPACT, Neuroscience Research Australia, Sydney, New South Wales, Australia
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
| | - Siobhan M Schabrun
- Center for Pain IMPACT, Neuroscience Research Australia, Sydney, New South Wales, Australia
- The Gray Centre for Mobility and Activity, University of Western Ontario, London, Canada
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14
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Avnit A, Zibman S, Alyagon U, Zangen A. Abnormal functional asymmetry and its behavioural correlates in adults with ADHD: A TMS-EEG study. PLoS One 2023; 18:e0285086. [PMID: 37228131 DOI: 10.1371/journal.pone.0285086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/15/2023] [Indexed: 05/27/2023] Open
Abstract
OBJECTIVES Abnormal functional brain asymmetry and deficient response inhibition are two core symptoms of attention deficit hyperactivity disorder (ADHD). We investigated whether these symptoms are inter-related and whether they are underlined by altered frontal excitability and by compromised interhemispheric connectivity. METHODS We studied these issues in 52 ADHD and 43 non-clinical adults by comparing: (1) stop-signal reaction time (SSRT); (2) frontal asymmetry of the N200 event-related potential component, which is evoked during response inhibition and is lateralised to the right hemisphere; (3) TMS-evoked potential (TEP) in the right frontal hemisphere, which is indicative of local cortical excitability; and (4) frontal right-to-left interhemispheric TMS signal propagation (ISP), which is reversely indicative of interhemispheric connectivity. RESULTS Compared to controls, the ADHD group demonstrated elongated SSRT, reduced N200 right-frontal-asymmetry, weaker TEP, and stronger ISP. Moreover, in the ADHD group, N200 right-frontal-asymmetry correlated with SSRT, with TEP, and with symptoms severity. Conversely, no relationship was observed between ISP and N200 right-frontal-asymmetry, and both TEP and ISP were found to be unrelated to SSRT. CONCLUSIONS Our results indicate that abnormal frontal asymmetry is related to a key cognitive symptom in ADHD and suggest that it is underlined by reduced right-frontal excitability.
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Affiliation(s)
- Amir Avnit
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Centre for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Samuel Zibman
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Centre for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Uri Alyagon
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Centre for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Abraham Zangen
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Centre for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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15
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Julkunen P, Kimiskidis VK, Belardinelli P. Special issue on TMS-EEG methods, data analysis and processing. J Neurosci Methods 2023; 383:109735. [PMID: 36374722 DOI: 10.1016/j.jneumeth.2022.109735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Vasilios K Kimiskidis
- 1st Department of Neurology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Paolo Belardinelli
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Italy; Department of Neurology & Stroke, University of Tübingen, Germany; Hertie Institute for Clinical Brain Research, University of Tübingen, Germany.
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