Bocci Tommaso, Marceglia Sara, Vergari Maurizio, Cognetto Valeria, Cogiamanian Filippo, Sartucci Ferdinando, Priori Alberto
Fondazione IRCCS "Ca' Granda" Ospedale Maggiore di Milano, Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Milan, Italy; Unità Operativa di Neurologia, Dipartimento di Neuroscienze, Università di Pisa, Pisa, Italy;
Fondazione IRCCS "Ca' Granda" Ospedale Maggiore di Milano, Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Milan, Italy; Dipartimento di Ingegneria e Architettura, Università degli Studi di Trieste, Trieste, Italy; and.
J Neurophysiol. 2015 Jul;114(1):440-6. doi: 10.1152/jn.00490.2014. Epub 2015 Apr 29.
This study aimed to assess the effects of thoracic anodal and cathodal transcutaneous spinal direct current stimulation (tsDCS) on upper and lower limb corticospinal excitability. Although there have been studies assessing how thoracic tsDCS influences the spinal ascending tract and reflexes, none has assessed the effects of this technique over upper and lower limb corticomotor neuronal connections. In 14 healthy subjects we recorded motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) from abductor hallucis (AH) and hand abductor digiti minimi (ADM) muscles before (baseline) and at different time points (0 and 30 min) after anodal or cathodal tsDCS (2.5 mA, 20 min, T9-T11 level). In 8 of the 14 subjects we also tested the soleus H reflex and the F waves from AH and ADM before and after tsDCS. Both anodal and cathodal tsDCS left the upper limb MEPs and F wave unchanged. Conversely, while leaving lower limb H reflex unchanged, they oppositely affected lower limb MEPs: whereas anodal tsDCS increased resting motor threshold [(mean ± SE) 107.33 ± 3.3% increase immediately after tsDCS and 108.37 ± 3.2% increase 30 min after tsDCS compared with baseline] and had no effects on MEP area and latency, cathodal tsDCS increased MEP area (139.71 ± 12.9% increase immediately after tsDCS and 132.74 ± 22.0% increase 30 min after tsDCS compared with baseline) without affecting resting motor threshold and MEP latency. Our results show that tsDCS induces polarity-specific changes in corticospinal excitability that last for >30 min after tsDCS offset and selectively affect responses in lower limb muscles innervated by lumbar and sacral motor neurons.
本研究旨在评估胸部阳极和阴极经皮脊髓直流电刺激（tsDCS）对上下肢皮质脊髓兴奋性的影响。尽管已有研究评估胸部tsDCS如何影响脊髓上行通路和反射，但尚无研究评估该技术对上下肢皮质运动神经元连接的影响。在14名健康受试者中，我们记录了在阳极或阴极tsDCS（2.5 mA，20分钟，T9 - T11水平）之前（基线）以及不同时间点（0和30分钟）经颅磁刺激（TMS）诱发的拇收肌（AH）和手部小指展肌（ADM）的运动诱发电位（MEP）。在14名受试者中的8名中，我们还测试了tsDCS前后比目鱼肌的H反射以及AH和ADM的F波。阳极和阴极tsDCS均未改变上肢MEP和F波。相反，虽然下肢H反射未变，但它们对下肢MEP产生了相反的影响：阳极tsDCS增加了静息运动阈值[（平均值±标准误）与基线相比，tsDCS后立即增加107.33±3.3%，tsDCS后30分钟增加108.37±3.2%]，且对MEP面积和潜伏期无影响，而阴极tsDCS增加了MEP面积[与基线相比，tsDCS后立即增加139.71±12.9%，tsDCS后30分钟增加132.74±22.0%]，但不影响静息运动阈值和MEP潜伏期。我们的结果表明，tsDCS在tsDCS停止后>30分钟内诱导皮质脊髓兴奋性发生极性特异性变化，并选择性地影响由腰段和骶段运动神经元支配的下肢肌肉的反应。
