Grasso Paolo A, Tonolli Elena, Bortoletto Marta, Miniussi Carlo
Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, TN, Italy; Department of Neuroscience, Psychology, Pharmacology and Child Health, University of Florence, Florence, Italy.
Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, TN, Italy.
Brain Res. 2021 Feb 15;1753:147227. doi: 10.1016/j.brainres.2020.147227. Epub 2020 Dec 30.
The application of anodal transcranial direct current stimulation (AtDCS) is generally associated with increased neuronal excitability and enhanced cognitive functioning. Nevertheless, previous work showed that applying this straight reasoning does not always lead to the desired results at behavioural level. Here, we investigated electrophysiological markers of AtDCS-mediated effects on visuo-spatial contextual learning (VSCL). In order to assess cortical excitability changes after 3 mA AtDCS applied over posterior parietal cortex, event-related potentials (ERPs) were collected during task performance. Additionally, AtDCS-induced effects on cortical excitability were explored by measuring TMS-evoked potentials (TEPs) collected before AtDCS, after AtDCS and after AtDCS and VSCL interaction. Behavioural results revealed that the application of AtDCS induced a reduction of VSCL. At the electrophysiological level, ERPs showed enhanced cortical response (P2 component) in the group receiving Real-AtDCS as compared to Sham-AtDCS. Cortical responsiveness at rest as measured by TEP, did not indicate any significant difference between Real- and Sham-tDCS groups, albeit a trend was present. Overall, our results suggest that AtDCS increases cortical response to incoming visuo-spatial stimuli, but with no concurrent increase in learning. Detrimental effects on behaviour could result from the interaction between AtDCS- and task-mediated cortical activation. This interaction might enhance cortical excitability and hinder normal task-related neuroplastic phenomena subtending learning.
阳极经颅直流电刺激（AtDCS）的应用通常与神经元兴奋性增加和认知功能增强有关。然而，先前的研究表明，运用这种直接的推理在行为层面并不总是能产生预期的结果。在此，我们研究了AtDCS介导的对视觉空间情境学习（VSCL）影响的电生理标志物。为了评估在顶叶后皮质施加3毫安AtDCS后皮质兴奋性的变化，在任务执行过程中收集事件相关电位（ERP）。此外，通过测量在AtDCS之前、AtDCS之后以及AtDCS与VSCL相互作用之后收集的经颅磁刺激诱发电位（TEP），探索AtDCS对皮质兴奋性的影响。行为结果显示，AtDCS的应用导致VSCL降低。在电生理水平上，与假刺激AtDCS组相比，接受真实AtDCS的组中ERP显示皮质反应增强（P2成分）。通过TEP测量的静息时皮质反应性，在真实和假刺激tDCS组之间未显示出任何显著差异，尽管存在一种趋势。总体而言，我们的结果表明，AtDCS增加了皮质对传入视觉空间刺激的反应，但学习并没有同时增加。AtDCS与任务介导的皮质激活之间的相互作用可能导致对行为的有害影响。这种相互作用可能会增强皮质兴奋性并阻碍支持学习的正常任务相关神经可塑性现象。
