Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK.
Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK.
Brain Stimul. 2019 May-Jun;12(3):684-692. doi: 10.1016/j.brs.2019.01.016. Epub 2019 Jan 28.
Recent studies have shown that neurophysiological outcomes of transcranial direct current stimulation (TDCS) are influenced by current flow in brain regions between the electrodes, and in particular the orientation of current flow relative to the cortical surface.
We asked whether the directional effects of TDCS on physiological measures in the motor system would also be observed on motor behaviours.
We applied TDCS during the practice of a ballistic movement task to test whether it affected learning or the retention of learning 48 h later. TDCS electrodes were oriented perpendicular to the central sulcus and two current orientations were used (posterior-anterior, TDCS; and anterior-posterior, TDCS). Transcranial magnetic stimulation (TMS) was used to assess whether changes in corticospinal excitability reflected any behavioural changes.
Directional TDCS impaired the retention of learning on the ballistic movement task compared to TDCS and a sham condition. Although TDCS had no effect on learning or retention, it blocked the typical increase in corticospinal excitability after a period of motor practice.
Our results extend on previous reports of TDCS producing directionally specific changes in neurophysiological outcomes by showing that current direction through a cortical target also impacts upon behavioural outcomes. In addition, changes in corticospinal excitability after a period of motor practice are not causally linked to behavioural learning.
最近的研究表明，经颅直流电刺激（TDCS）的神经生理学结果受到电极之间脑区电流流动的影响，特别是电流流动相对于皮质表面的方向。
我们想知道 TDCS 对运动系统生理测量的定向影响是否也会在运动行为上观察到。
我们在进行弹道运动任务的练习过程中应用 TDCS，以测试其是否会影响 48 小时后的学习或学习的保留。TDCS 电极垂直于中央沟放置，使用两种电流方向（前后向 TDCS；和前后向 TDCS）。经颅磁刺激（TMS）用于评估皮质脊髓兴奋性的变化是否反映了任何行为变化。
与 TDCS 和假刺激相比，定向 TDCS 损害了弹道运动任务的学习保留。虽然 TDCS 对学习或保留没有影响，但它阻止了运动练习一段时间后皮质脊髓兴奋性的典型增加。
我们的结果通过表明皮质目标的电流方向也会影响行为结果，扩展了之前关于 TDCS 产生神经生理学结果的定向特异性变化的报告。此外，运动练习一段时间后皮质脊髓兴奋性的变化与行为学习没有因果关系。
