Modeling motor-evoked potentials from neural field simulations of transcranial magnetic stimulation

Marcus T. Wilson, Bahar Moezzi, Nigel C. Rogasch

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: To develop a population-based biophysical model of motor-evoked potentials (MEPs) following transcranial magnetic stimulation (TMS). Methods: 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. Significance: 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.

Original languageEnglish
Pages (from-to)412-428
Number of pages17
JournalClinical Neurophysiology
Volume132
Issue number2
DOIs
Publication statusPublished - Feb 2021

Keywords

  • Calcium dependent plasticity
  • Cortical plasticity
  • Corticomotor system
  • MEP
  • Modeling
  • Motor evoked potential
  • Neural field theory
  • Paired-pulse
  • TMS
  • Theta burst stimulation
  • Transcranial magnetic stimulation
  • cTBS
  • iTBS
  • rTMS

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)

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