Wilson, M.T.Moezzi, B.Rogasch, N.C.2021-06-032021-06-032021Clinical Neurophysiology, 2021; 132(2):412-4281388-24571872-8952http://hdl.handle.net/2440/130573Objective To develop a population-based biophysical model of motor-evoked potentials (MEPs) following transcranial magnetic stimulation (TMS).<h4>Methods</h4>We combined an existing MEP model with population-based cortical modeling. Layer 2/3 excitatory and inhibitory neural populations, modeled with neural-field theory, are stimulated with TMS and feed layer 5 corticospinal neurons, which also couple directly but weakly to the TMS pulse. The layer 5 output controls mean motoneuron responses, which generate a series of single motor-unit action potentials that are summed to estimate a MEP. Results A MEP waveform was generated comparable to those observed experimentally. The model captured TMS phenomena including a sigmoidal input-output curve, common paired pulse effects (short interval intracortical inhibition, intracortical facilitation, long interval intracortical inhibition) including responses to pharmacological interventions, and a cortical silent period. Changes in MEP amplitude following theta burst paradigms were observed including variability in outcome direction. Conclusions The model reproduces effects seen in common TMS paradigms.<h4>Significance</h4>The model allows population-based modeling of changes in cortical dynamics due to TMS protocols to be assessed in terms of changes in MEPs, thus allowing a clear comparison between population-based modeling predictions and typical experimental outcome measures.en© 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.Calcium dependent plasticityCortical plasticityCorticomotor systemMEPModelingMotor evoked potentialNeural field theoryPaired-pulseTMSTheta burst stimulationTranscranial magnetic stimulationcTBSiTBSrTMSJournal article100003400210.1016/j.clinph.2020.10.0320006175471000122-s2.0-85099179987563058Rogasch, N.C. [0000-0002-4484-1069]