Training voluntary motor suppression with real-time feedback of motor evoked potentials.
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.
Department of Psychology and Neurosciences Graduate Program, University of California, San Diego, California.
D S Adnan
DS
Majid
Department of Psychology and Neurosciences Graduate Program, University of California, San Diego, California.
Christina
C
Lewis
Department of Psychology and Neurosciences Graduate Program, University of California, San Diego, California adamaron@ucsd.edu.
Adam R
AR
Aron
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003463:Cues; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology*; D005260:Female; D006225:Hand / Q000294:innervation; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
inhibitory control; mental imagery; transcranial magnetic stimulation