Lang Nicolas, Siebner Hartwig R, Ernst Diana, Nitsche Michael A, Paulus Walter, Lemon Roger N, Rothwell John C
Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom.
Biol Psychiatry. 2004 Nov 1;56(9):634-9. doi: 10.1016/j.biopsych.2004.07.017.
Rapid-rate repetitive transcranial magnetic stimulation (rTMS) can produce a lasting increase in cortical excitability in healthy subjects or induce beneficial effects in patients with neuropsychiatric disorders; however, the conditioning effects of rTMS are often subtle and variable, limiting therapeutic applications. Here we show that magnitude and direction of after-effects induced by rapid-rate rTMS depend on the state of cortical excitability before stimulation and can be tuned by preconditioning with transcranial direct current stimulation (tDCS).
Ten healthy volunteers received a 20-sec train of 5-Hz rTMS given at an intensity of individual active motor threshold to the left primary motor hand area. This interventional protocol was preconditioned by 10 min of anodal, cathodal, or sham tDCS. We used single-pulse TMS to assess corticospinal excitability at rest before, between, and after the two interventions.
The 5-Hz rTMS given after sham tDCS failed to produce any after-effect, whereas 5-Hz rTMS led to a marked shift in corticospinal excitability when given after effective tDCS. The direction of rTMS-induced plasticity critically depended on the polarity of tDCS conditioning.
Preconditioning with tDCS enhances cortical plasticity induced by rapid-rate rTMS and can shape the direction of rTMS-induced after-effects.
快速重复经颅磁刺激（rTMS）可使健康受试者的皮质兴奋性产生持久增加，或对神经精神疾病患者产生有益影响；然而，rTMS的条件效应往往较为微妙且多变，限制了其治疗应用。在此我们表明，快速rTMS诱导的后效应的大小和方向取决于刺激前的皮质兴奋性状态，并且可以通过经颅直流电刺激（tDCS）预处理来调节。
10名健康志愿者接受了20秒的5赫兹rTMS序列，以个体主动运动阈值强度刺激左侧初级运动手区。该干预方案通过10分钟的阳极、阴极或假tDCS进行预处理。我们使用单脉冲TMS在两次干预之前、之间和之后评估静息状态下的皮质脊髓兴奋性。
假tDCS后给予的5赫兹rTMS未能产生任何后效应，而有效tDCS后给予的5赫兹rTMS导致皮质脊髓兴奋性出现明显变化。rTMS诱导的可塑性方向关键取决于tDCS预处理的极性。
tDCS预处理增强了快速rTMS诱导的皮质可塑性，并可塑造rTMS诱导的后效应方向。
