Bocci Tommaso, Vannini Beatrice, Torzini Antonio, Mazzatenta Andrea, Vergari Maurizio, Cogiamanian Filippo, Priori Alberto, Sartucci Ferdinando
Department of Clinical and Experimental Medicine, Unit of Neurology, Pisa University Medical School, Pisa, Italy; Department of Neurological and Neurosensorial Sciences, Neurology and Clinical Neurophysiology Section, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
Department of Clinical and Experimental Medicine, Unit of Neurology, Pisa University Medical School, Pisa, Italy.
Neurosci Lett. 2014 Aug 22;578:75-9. doi: 10.1016/j.neulet.2014.06.037. Epub 2014 Jun 23.
Transcutaneous spinal direct current stimulation (tsDCS) is a new promising technique for modulating spinal cord function in humans. However, its effects on corticospinal pathways and lower motorneuron excitability are poorly understood. We studied the effects of tsDCS on motor unit recruitment by evaluating changes in motor unit number (MUNE) and peripheral silent period (PSP) after sham (s-tsDCS), anodal (a-tsDCS) and cathodal (c-tsDCS) tsDCS applied either over the cervical or the lower thoracic spinal cord in healthy subjects. For the calculation of MUNE we used the multipoint incremental technique recording from either the ulnar nerve innervated abductor digiti minimi (ADM) or the median nerve innervated abductor pollicis brevis (APB) muscle. c-tsDCS dramatically increases MUNE values following cervical polarization, while sham and anodal polarization have no significant effect (APB: F(4,99)=26.4, p<0.001, two-way repeated measures ANOVA with "time" and "stimulation" as factors; ADM: F(4,99)=22.1, p<0.0001). At the same time, c-tsDCS dampened PSP respect to sham and anodal conditions (p<0.0001). Interestingly, also thoracic c-tsDCS significantly improved motor unit recruitment compared with both s-tsDCS and a-tsDCS (APB: F(4,99)=20.1, p<0.0001; ADM: F(4,99)=16.6, p<0.0001). Our data in healthy subjects suggest that tsDCS, possibly also through supraspinal effects, could provide a novel therapeutic tool in managing several pathological conditions characterized by reduced motor unit recruitment, such as stroke and spinal cord injuries.
经皮脊髓直流电刺激（tsDCS）是一种用于调节人体脊髓功能的有前景的新技术。然而，其对皮质脊髓通路和下运动神经元兴奋性的影响尚不清楚。我们通过评估健康受试者在假刺激（s-tsDCS）、阳极（a-tsDCS）和阴极（c-tsDCS）经皮脊髓直流电刺激分别作用于颈段或胸段脊髓后运动单位数量（MUNE）和外周静息期（PSP）的变化，研究了经皮脊髓直流电刺激对运动单位募集的影响。为了计算运动单位数量，我们使用多点递增技术，从尺神经支配的小指展肌（ADM）或正中神经支配的拇短展肌（APB）记录。颈段极化后，阴极经皮脊髓直流电刺激显著增加运动单位数量值，而假刺激和阳极极化无显著影响（APB：F(4,99)=26.4，p<0.001，以“时间”和“刺激”为因素的双向重复测量方差分析；ADM：F(4,99)=22.1，p<0.0001）。同时，与假刺激和阳极刺激条件相比，阴极经皮脊髓直流电刺激减弱了外周静息期（p<0.0001）。有趣的是，与假刺激和阳极经皮脊髓直流电刺激相比，胸段阴极经皮脊髓直流电刺激也显著改善了运动单位募集（APB：F(4,99)=20.1，p<0.0001；ADM：F(4,99)=16.6，p<0.0001）。我们在健康受试者中的数据表明，经皮脊髓直流电刺激可能也通过脊髓上的作用，为管理几种以运动单位募集减少为特征的病理状况，如中风和脊髓损伤，提供一种新的治疗工具。
