School of Pharmacy and Medical Sciences and The Sansom Institute, University of South Australia, Adelaide, Australia.
Clin Neurophysiol. 2012 May;123(5):1002-9. doi: 10.1016/j.clinph.2011.09.019. Epub 2011 Oct 22.
The aim of our study was to use peristimulus frequencygram (PSF) constructed from single motor unit recordings to further characterise the responses evoked by low intensity TMS.
Twelve healthy subjects (age 32 ± 11 years) received single-pulse TMS over the first dorsal interosseus (FDI) motor area during weak isometric index finger abduction. Several hundred stimuli were delivered at a frequency of ∼0.3 Hz and at an intensity of 79-110% of active motor threshold. FDI electromyogram (EMG) was recorded with surface and intramuscular fine wire electrodes. For single motor units, data analysis involved construction of a peristimulus time histogram (PSTH) and PSF. Surface EMG analysis involved signal averaging. Cumulative sums (CUSUMs) were calculated for SEMG, PSTH, and PSF data.
Forty-five single motor units were identified. The average number of stimuli per unit was 201 ± 112. Characterisation of the response evoked by TMS differed with the use of SEMG, PSTH, and PSF CUSUMs.
The duration of the EMG silence that follows the MEP during voluntary contraction was longer in the PSF than SEMG and PSTH.
These findings highlight the importance of using both probability and frequency-based analysis when determining the duration of inhibitory events in peripheral recordings.
我们的研究旨在使用源自单个运动单位记录的刺激频率图（PSF）进一步描述由低强度 TMS 诱发的反应。
12 名健康受试者（年龄 32 ± 11 岁）在弱等距食指外展期间接受来自第一背侧间骨（FDI）运动区的单次脉冲 TMS。以约 0.3 Hz 的频率和 79-110%的主动运动阈值强度递送数百个刺激。FDI 肌电图（EMG）使用表面和肌内细电线电极记录。对于单个运动单位，数据分析涉及构建刺激时间直方图（PSTH）和 PSF。表面 EMG 分析涉及信号平均。为 SEMG、PSTH 和 PSF 数据计算累积和（CUSUM）。
鉴定出 45 个单个运动单位。每个单位的平均刺激数为 201 ± 112。TMS 诱发反应的特征因 SEMG、PSTH 和 PSF CUSUM 而异。
在自愿收缩期间，MEP 之后的 EMG 静默持续时间在 PSF 中比 SEMG 和 PSTH 长。
这些发现强调了当确定外周记录中抑制事件的持续时间时，使用基于概率和基于频率的分析的重要性。
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