Kallioniemi Elisa, Säisänen Laura, Könönen Mervi, Awiszus Friedemann, Julkunen Petro
Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
Clin Neurophysiol. 2014 Nov;125(11):2247-2252. doi: 10.1016/j.clinph.2014.03.012. Epub 2014 Mar 22.
We evaluated the induction of corticospinal silent period (SP) using transcranial magnetic stimulation (TMS) at stimulation intensities normalized to resting motor threshold (rMT) or silent period thresholds (SPTs). The aim was to reduce the characteristic inter-individual variation in SP measurements in healthy population to improve the sensitivity of such measurements.
The cortical representation area of the right hand musculature of 12 healthy subjects was stimulated with navigated TMS with varying stimulating intensities. Subsequently, the individual SPTs for eliciting SPs of 20, 30, and 50ms in duration were determined from the input-output characteristics.
While SPT for 20 and 50ms SPs differed from rMT, the SPT for 30ms was similar to rMT. Nevertheless, the inter-individual variation in SP duration was reduced significantly at 120% of SPT30 when compared with SP durations obtained at 120% of rMT.
Inter-individual variation in the SP duration decreases when applying TMS at stimulation intensities normalized to the individual SPTs instead to the rMT. This makes the SP duration more specific to inhibition and less affected by changes in cortical excitability.
Use of individual SPTs may improve the sensitivity of the SP measures in studies with inter-individual design.
我们使用经颅磁刺激（TMS），在刺激强度标准化为静息运动阈值（rMT）或静息期阈值（SPT）的情况下，评估皮质脊髓静息期（SP）的诱导情况。目的是减少健康人群中SP测量的个体间特征性差异，以提高此类测量的敏感性。
对12名健康受试者右手肌肉组织的皮质代表区进行导航TMS刺激，刺激强度不同。随后，根据输入-输出特性确定引发持续时间为20、30和50毫秒的SP的个体SPT。
虽然20毫秒和50毫秒SP的SPT与rMT不同，但30毫秒的SPT与rMT相似。然而，与在rMT的120%时获得的SP持续时间相比，在SPT30的120%时，SP持续时间的个体间差异显著减小。
当以个体SPT而非rMT对刺激强度进行标准化来应用TMS时，SP持续时间的个体间差异会减小。这使得SP持续时间对抑制作用更具特异性，且受皮质兴奋性变化的影响更小[1,2]。
在个体间设计的研究中，使用个体SPT可能会提高SP测量的敏感性。
