Nikolov Petyo, Zimmermann Johanna V, Hassan Shady S, Albrecht Philipp, Schnitzler Alfons, Groiss Stefan J
Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
Exp Brain Res. 2021 Feb;239(2):583-589. doi: 10.1007/s00221-020-06010-7. Epub 2020 Dec 29.
Conditioning transcranial magnetic stimulation (TMS) with subthreshold conditioning stimulus followed by supra-threshold test stimulus at inter-stimulus intervals (ISI) of 1-5 ms results in inhibition (SICI), while ISI at 10-15 ms results in facilitation (ICF). One concerning issue, applying ICF/SICI protocols on patients is the substantial protocol variability. Here, we hypothesized that increasing the number of CS could result in more robust ICF/SICI protocols. Twenty healthy subjects participated in the study. Motor-evoked potentials (MEP) were obtained from conditioning TMS with a varying number of conditioning stimuli in 3, 4, 10, and 15 ms ISI over the primary motor cortex. MEP amplitudes were then compared to examine excitability. TMS with 3, 5, and 7 conditioning stimuli but not with one conditioning stimulus induced ICF. Moreover, 10 ms ISI produced stronger ICF than 15 ms ISI. Significant SICI was only induced with one conditioning stimulus. Besides, 3 ms ISI resulted in stronger SICI than 4 ms ISI. Only a train of conditioning stimuli induced stable ICF and may be more advantageous than the classical paired pulse ICF paradigm.
用阈下条件刺激对经颅磁刺激（TMS）进行条件设定，随后在1 - 5毫秒的刺激间隔（ISI）施加阈上测试刺激会导致抑制（短间隔皮层内抑制，SICI），而10 - 15毫秒的ISI则会导致易化（皮层内易化，ICF）。在患者身上应用ICF/SICI方案时，一个令人担忧的问题是方案存在很大的变异性。在此，我们假设增加条件刺激的数量可能会产生更稳定的ICF/SICI方案。20名健康受试者参与了该研究。通过在初级运动皮层上以3、4、10和15毫秒的ISI施加不同数量的条件刺激来进行条件TMS，从而获得运动诱发电位（MEP）。然后比较MEP的振幅以检查兴奋性。3、5和7次条件刺激的TMS可诱导ICF，但单次条件刺激则不能。此外，10毫秒的ISI比15毫秒的ISI产生更强的ICF。仅单次条件刺激可诱导出显著的SICI。此外，3毫秒的ISI比4毫秒的ISI产生更强的SICI。只有一连串的条件刺激能诱导出稳定的ICF，并且可能比经典的配对脉冲ICF范式更具优势。
