Sensory Motor Performance Program, Rehabilitation Institute of Chicago, 345 E. Superior Street, Chicago, IL 60611, USA.
Brain Stimul. 2010 Jan;3(1):42. doi: 10.1016/j.brs.2009.06.005.
Because we are interested in non-invasive transcranial brain stimulation as an adjuvant to post-stroke walking therapy, we applied direct current stimulation (tDCS) preferentially to either the left or right lower limb motor cortex (M1) in two separate sessions and assessed the resulting modulation in both cortices.
OBJECTIVE/HYPOTHESIS: We hypothesized that tDCS applied preferentially to one lower limb M1 of healthy subjects would induce between-hemisphere opposite sign modulation.
Transcranial magnetic stimulation (TMS) with the coil offset 2 cm either side of vertex was used to assess the percent change in rectified motor evoked potential (MEP) area recorded bilaterally from vastus lateralis (VL) and tibialis anterior (TA) of 10 subjects during weak tonic contraction.
ANOVA revealed an up-regulation of the target cortex and a down-regulation of the non-target cortex (p = 0.001) and no effects of hemisphere (left, right) or muscle (TA, VL). Significant modulation was evident in 78% of VL and TA muscles (all p < 0.05). Excitability increased in 60%, but decreased in 18%. For 43% when excitability increased, a simultaneous decrease in excitability was evident in homologous muscle responses providing support for our hypothesis.
The results indicate a modest effectiveness and focality of anodal tDCS when applied to lower limb M1, suggesting in a human model that the strength and depth of polarizing cortical currents induced by tDCS likely depend on inter-individual differences in the electrical properties of superficial brain structures.
因为我们对非侵入性经颅脑刺激作为中风后行走治疗的辅助手段很感兴趣，所以我们在两次单独的会话中优先将直流电刺激（tDCS）应用于左或右下肢运动皮层（M1），并评估了两个皮层的结果调节。
目的/假设：我们假设，将 tDCS 优先应用于健康受试者的一条下肢 M1，将诱导半球之间的相反符号调节。
使用线圈在顶点两侧偏移 2 厘米的经颅磁刺激（TMS）来评估 10 名受试者在弱紧张收缩期间从股外侧肌（VL）和胫骨前肌（TA）双侧记录的经整流运动诱发电位（MEP）区域的百分比变化。
方差分析显示目标皮层的上调和非目标皮层的下调（p = 0.001），且无半球（左、右）或肌肉（TA、VL）的影响。78%的 VL 和 TA 肌肉均有明显的调制（均 p < 0.05）。兴奋性增加了 60%，但减少了 18%。对于兴奋性增加的 43%，在同源肌肉反应中同时出现了兴奋性的降低，这为我们的假设提供了支持。
结果表明，当应用于下肢 M1 时，阳极 tDCS 的效果和焦点适度，这表明在人类模型中，tDCS 诱导的皮质电流的强度和深度可能取决于大脑表面结构的个体间电特性的差异。
