Background: The analysis of cortical responses to transcranial magnetic stimulation (TMS) recorded by electroencephalography (EEG) has been successfully applied to study human cortical physiology. However, in addition to the (desired) activation of cortical neurons and fibers, TMS also causes (undesired) indirect brain responses through auditory and somatosensory stimulation, which may contribute significantly to the overall EEG signal and mask the effects of intervention on direct cortical responses.
Objectives: To test differences in EEG responses to real TMS at intensities above and below resting motor threshold (RMT) and a realistic sham stimulation.
Methods: 12 healthy subjects participated in one session in which single-pulse TMS was applied to the left motor cortex in 3 different blocks, 150 pulses per block: 110%RMT, 90%RMT and realistic sham stimulation. Cortical responses were collected by a 64 electrode EEG system. TMS evoked potentials (TEPs) and TMS induced oscillations were analyzed.
Methods: 12 healthy subjects participated in one session in which single-pulse TMS was applied to the left motor cortex in 3 different blocks, 150 pulses per block: 110%RMT, 90%RMT and realistic sham stimulation. Cortical responses were collected by a 64-channel EEG system. TMS evoked potentials (TEPs) and TMS induced oscillations were analyzed.
Results: TEPs from all conditions differed significantly, with TEPs from 110%RMT showing overall highest amplitudes and realistic sham lowest amplitudes. Sham stimulation had only minor effects on induced cortical oscillations compared to pre-stimulus baseline, TMS at 90%RMT resulted in a significant increase (50-200 m s) followed by a decrease (200-500 m s) in power of alpha and beta oscillations; TMS at 110% RMT led to an additional increase in beta power at late latencies (650-800 m s).
Conclusions: Real TMS of motor cortex results in cortical responses significantly different from realistic sham. These differences very likely reflect to a significant extent direct activation of neurons, rather than sensory evoked activity.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.brs.2018.08.003 | DOI Listing |
Clin Neurophysiol
January 2025
Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan; Department of Psychiatry, International University of Health and Welfare, Mita Hospital, Tokyo, Japan. Electronic address:
Objective: This study aimed to optimally evaluate the effect of the long-interval intracortical inhibition (LICI) in the dorsolateral prefrontal cortex (DLPFC) through transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) by eliminating the volume conductance with signal source estimation and using a realistic sham coil as a control.
Methods: We compared the LICI effects from the DLPFC between the active and sham stimulation conditions in 27 healthy participants. Evoked responses between the two conditions were evaluated at the sensor and source levels.
J Chem Phys
July 2024
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
Time-dependent density functional theory (TD-DFT) within a restricted excitation space is an efficient means to compute core-level excitation energies using only a small subset of the occupied orbitals. However, core-to-valence excitation energies are significantly underestimated when standard exchange-correlation functionals are used, which is partly traceable to systemic issues with TD-DFT's description of Rydberg and charge-transfer excited states. To mitigate this, we have implemented an empirically modified combination of configuration interaction with single substitutions (CIS) based on Kohn-Sham orbitals, which is known as "DFT/CIS.
View Article and Find Full Text PDFJ Cardiovasc Pharmacol
July 2024
Department of Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
Bull Math Biol
March 2024
Medical Device Research Institute, College of Science and Engineering, Flinders University, Tonsley Campus, 1284 South Rd, Clovelly Park, SA, 5042, Australia.
A two-stage model is proposed for investigating remodelling characteristics in bone over time and distance to the growth plate. The first stage comprises a partial differential equation (PDE) for bone density as a function of time and distance from the growth plate. This stage clarifies the contributions to changes in bone density due to remodelling and growth processes and tracks the rate at which new bone emanates from the growth plate.
View Article and Find Full Text PDFHGG Adv
April 2024
Department of Psychiatry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; Centre for PanorOmic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China. Electronic address:
Functional enrichment results typically implicate tissue or cell-type-specific biological pathways in disease pathogenesis and as therapeutic targets. We propose generalized linkage disequilibrium score regression (g-LDSC) that requires only genome-wide association studies (GWASs) summary-level data to estimate functional enrichment. The method adopts the same assumptions and regression model formulation as stratified linkage disequilibrium score regression (s-LDSC).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!