Effect of transcranial static magnetic stimulation on intracortical excitability in the contralateral primary motor cortex

• Published in: Neuroscience letters Vol. 723; p. 134871
• Main Authors: Shibata, Sumiya, Watanabe, Tatsunori, Yukawa, Yoshihiro, Minakuchi, Masatoshi, Shimomura, Ryota, Mima, Tatsuya
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.04.2020
• Subjects: Adult; Evoked Potentials, Motor - physiology; Female; Functional Laterality - physiology; Humans; Interhemispheric interaction; Intracortical facilitation (ICF); Male; Motor Cortex - physiology; Neural Inhibition - physiology; Short-latency intracortical inhibition (SICI); Transcranial Magnetic Stimulation - methods; Transcranial static magnetic stimulation (tSMS); Young Adult; M1; IHF; FDI; IHI; Intracortical facilitation (ICF); ANOVA; Short-latency intracortical inhibition (SICI); NMDA; rMT; Interhemispheric interaction; SICI; EMG; ISI; Transcranial static magnetic stimulation (tSMS); dPM; SMA; NIBS; ICF; CS; tSMS; tDCS; GABA; MEP; TMS; rTMS; TS
• ISSN: 0304-3940; 1872-7972; 1872-7972
• DOI: 10.1016/j.neulet.2020.134871

•Transcranial static magnetic stimulation was given to the left motor cortex.•Intracortical facilitation on the right side decreased.•Magnets can modulate human contralateral interneuronal facilitatory circuits. Transcranial static magnetic stimulation (tSMS) is a new technique of non-invasive brain stimulation using a small, high-powered neodymium magnet placed on the scalp. It can reduce cortical excitability below the magnet. The aim of this study was to investigate the effect of tSMS on the intracortical excitability of the primary motor cortex (M1) contralateral to the M1 where the magnet was placed. Fourteen right-handed healthy subjects participated in this experiment. TSMS was applied over the left M1 for 20 min. Single-pulse and paired-pulse transcranial magnetic stimulation (TMS) was applied over the right M1 to assess corticospinal excitability, short-latency intracortical inhibition (SICI), and intracortical facilitation (ICF) before and immediately after the intervention. ICF decreased significantly after tSMS, whereas corticospinal excitability and SICI did not change. This study suggests that tSMS applied over the M1 for 20 min has a remote modulatory effect on the interneuronal facilitatory circuit in the contralateral M1. The ability of tSMS to modulate neuronal activities in the remote cortex could expand the possibility of its clinical use.