Open AccessEffect of different pulse numbers of transcranial magnetic stimulation on motor cortex excitability: Single‐blind, randomized cross‐over design
Author(s) -
Tang ZhiMing,
Xuan ChunYu,
Li Xin,
Dou ZuLin,
Lan YuJie,
Wen HongMei
Publication year - 2019
Publication title -
cns neuroscience and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 69
eISSN - 1755-5949
pISSN - 1755-5930
DOI - 10.1111/cns.13248
Subject(s) - transcranial magnetic stimulation , motor cortex , stimulation , pulse (music) , evoked potential , neuroscience , medicine , psychology , physics , detector , optics
Aims We aimed to investigate the effect of different pulse numbers of high‐frequency repetitive transcranial magnetic stimulation (rTMS) over the motor cortex on cortical excitability in healthy participants. Methods Fifteen healthy participants received 600 and 1200 pulses of 5‐Hz rTMS on separate days in a random order. Stimulation (duration, 2 seconds and interval, 1 seconds) was delivered over the left primary motor cortex for the hand, at 90% of resting motor threshold (rMT). The rMT and motor evoked potential (MEP) were measured before stimulation, and at 0 and 30 minutes after rTMS. Results No significant differences were observed between the two conditions for MEP ( P = .919) or rMT ( P = .266). Compared with baseline, MEP was increased significantly at 0 ( P < .001) and 30 minutes ( P < .001) after stimulation. After stimulation, rMT was decreased at 0 minute for the 600 and 1200 pulse conditions ( P < .001), but had recovered by 30 minutes ( P = .073). Conclusion Subthreshold 5‐Hz rTMS increased motor cortex excitability in healthy humans. However, the number of pulses may exhibit a ceiling effect in that beyond a certain point, that is, increasing the number of pulses may exhibit no further increase in cortical excitability.