Pellicciari Maria Concetta, Miniussi Carlo, Ferrari Clarissa, Koch Giacomo, Bortoletto Marta
Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; Neuroscience Section, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
Clin Neurophysiol. 2016 Jan;127(1):621-628. doi: 10.1016/j.clinph.2015.03.002. Epub 2015 Mar 17.
To evaluate the effects of several single TMS pulses, delivered at two different inter-trial intervals (ITIs), on corticospinal excitability.
Twelve healthy volunteers participated in two experimental sessions, during which TMS pulses were delivered at random or at fixed ITIs. The TMS single pulse-induced modulation of corticospinal output (motor evoked potential amplitude - MEP) was evaluated on-line. Each session began with a baseline block, followed by 10 blocks, with 20 TMS pulses each. Intra- and inter-block effects were valuated using an ANOVA model, through nested random effect on subjects considering the subject-specific variability.
The delivery of successive TMS pulses significantly changed both intra-block and inter-block cortical excitability, as demonstrated by an increase in the amplitude of MEPs (p<0.001) and supported through trend analyses, showing a perfect linear trend for inter-block levels (R(2)=1) and nearly linear trend for intra-block levels (R(2)=0.97). The MEPs significantly increased when the TMS pulses were delivered at both random and fixed ITIs.
Single TMS pulses induce cumulative changes in neural activity during the same stimulation, resulting in a motor cortical excitability increase.
Particular attention should be taken when several single TMS pulses are delivered in research and clinical settings for diagnostic and therapeutic purposes.
评估在两种不同的试次间隔（ITIs）下施加的多个单脉冲经颅磁刺激（TMS）对皮质脊髓兴奋性的影响。
12名健康志愿者参与了两个实验阶段，在此期间TMS脉冲以随机或固定的ITIs施加。在线评估TMS单脉冲诱发的皮质脊髓输出调制（运动诱发电位幅度 - MEP）。每个阶段开始于一个基线块，随后是10个块，每个块有20个TMS脉冲。使用方差分析模型评估块内和块间效应，通过考虑个体特异性变异性的对受试者的嵌套随机效应进行评估。
连续TMS脉冲的施加显著改变了块内和块间的皮质兴奋性，表现为MEP幅度增加（p<0.001），并通过趋势分析得到支持，显示块间水平呈完美线性趋势（R(2)=1），块内水平呈近似线性趋势（R(2)=0.97）。当TMS脉冲以随机和固定的ITIs施加时，MEP均显著增加。
单个TMS脉冲在相同刺激期间诱导神经活动的累积变化，导致运动皮质兴奋性增加。
在研究和临床环境中，出于诊断和治疗目的施加多个单TMS脉冲时应特别注意。
