Training voluntary motor suppression with real-time feedback of motor evoked potentials

J Neurophysiol. 2015 May 1;113(9):3446-52. doi: 10.1152/jn.00992.2014. Epub 2015 Mar 4.


Training people to suppress motor representations voluntarily could improve response control. We evaluated a novel training procedure of real-time feedback of motor evoked potentials (MEPs) generated by transcranial magnetic stimulation (TMS) over motor cortex. On each trial, a cue instructed participants to use a mental strategy to suppress a particular finger representation without overt movement. A single pulse of TMS was delivered over motor cortex, and an MEP-derived measure of hand motor excitability was delivered visually to the participant within 500 ms. In experiment 1, we showed that participants learned to reduce the excitability of a particular finger beneath baseline (selective motor suppression) within 30 min of practice. In experiment 2, we performed a double-blind study with 2 training groups (1 with veridical feedback and 1 with matched sham feedback) to show that selective motor suppression depends on the veridical feedback itself. Experiment 3 further demonstrated the importance of veridical feedback by showing that selective motor suppression did not arise from mere mental imagery, even when incentivized with reward. Thus participants can use real-time feedback of TMS-induced MEPs to discover an effective mental strategy for selective motor suppression. This high-temporal-resolution, trial-by-trial-feedback training method could be used to help people better control response tendencies and may serve as a potential therapy for motor disorders such as Tourette's and dystonia.

Keywords: inhibitory control; mental imagery; transcranial magnetic stimulation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Cues
  • Electromyography
  • Evoked Potentials, Motor / physiology*
  • Feedback, Physiological / physiology*
  • Female
  • Hand / innervation
  • Humans
  • Male
  • Motor Cortex / physiology*
  • Transcranial Magnetic Stimulation
  • Young Adult