Effects of transcranial direct current stimulation on the excitability of the leg motor cortex
Effects of transcranial direct current stimulation on the excitability of the leg motor cortex
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DOI：
10.1007/s00221-007-1093-y
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发表时间：
2007-09-01
影响因子：
2
通讯作者：
Gorassini, Monica A.
中科院分区：
文献类型：
--
作者：
Jeffery, Dean T.;Norton, Jonathan A.;Gorassini, Monica A.
经颅直流电刺激(TDC)在1 mA的强度下刺激人的运动皮质，可以有效地增加(通过阴阳极tDC)或降低(通过阴极tDC)皮质脊髓投射到手部肌肉的兴奋性。在这项研究中，我们研究了电流为2 mA的tDCs是否会对支配小腿肌肉的深层皮质结构的兴奋性产生类似的变化。与手部类似，在运动皮质的腿部区域用阳极刺激10min，皮质脊髓束投射到胫前肌的兴奋性增加，反映在经颅磁刺激诱发的运动诱发电位(MEP)的幅度增加。静息和背景收缩时记录的MEP波幅在阳极tDCs后增加，并在60min时与基线值相比分别升高59%和35%。然而，与手相反，在等值电流下的超极化阴极刺激对静息或背景收缩时记录到的TA肌的MEP的幅度影响很小。这些结果表明，用阴极tdcs抑制小腿运动皮质的兴奋性比用运动皮质的手区更困难。
Transcranial direct current stimulation (tDCS) of the human motor cortex at an intensity of 1 mA has been shown to be efficacious in increasing (via anodal tDCS) or decreasing (via cathodal tDCS) the excitability of corticospinal projections to muscles of the hand. In this study, we examined whether tDCS at currents of 2 mA could effect similar changes in the excitability of deeper cortical structures that innervate muscles of the lower leg. Similar to the hand area, 10 min of stimulation with the anode over the leg area of the motor cortex increased the excitability of corticospinal tract projections to the tibialis anterior (TA) muscle, as reflected by an increase in the amplitude of the motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation. MEP amplitudes recorded at rest and during a background contraction were increased following anodal tDCS and remained elevated at 60 min compared to baseline values by 59 and 35%, respectively. However, in contrast to the hand, hyperpolarizing cathodal stimulation at equivalent currents had minimal effect on the amplitude of the MEPs recorded at rest or during background contraction of the TA muscle. These results suggest that it is more difficult to suppress the excitability of the leg motor cortex with cathodal tDCS than the hand area of the motor cortex.