Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilians University, München, Germany.
Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilians University, München, Germany.
Conscious Cogn. 2020 Aug;83:102959. doi: 10.1016/j.concog.2020.102959. Epub 2020 Jun 2.
Anodal transcranial current stimulation (tDCS) to the left dorsolateral prefrontal cortex (DLPFC) has been shown to enhance working memory (WM) in neuropsychiatric patients. In healthy populations, however, tDCS obtains inconclusive results, mostly due to heterogeneous study and stimulation protocols. Here, we approached these issues by investigating effects of tDCS intensity on simultaneous WM performance with three cognitive loads by directly comparing findings of two double-blind, cross-over, sham-controlled experiments. TDCS was administrated to the left DLPFC at intensity of 1 mA (Experiment 1) or 2 mA (Experiment 2), while participants completed a verbal n-back paradigm (1-, 2-, 3-back). Analysis showed no overall effects of tDCS on WM, but a significant interaction with cognitive load. The present study suggests that cognitive load rather than tDCS intensity could be a decisive factor for effects on WM. Moreover, it emphasizes the need of thorough investigation on study parameters to develop more efficient stimulation protocols.
经颅直流电刺激（tDCS）作用于左侧背外侧前额叶皮层（DLPFC）已被证明可增强神经精神疾病患者的工作记忆（WM）。然而，在健康人群中，tDCS 的结果并不一致，这主要是由于研究和刺激方案存在异质性。在此，我们通过直接比较两项双盲、交叉、假刺激对照实验的结果，研究 tDCS 强度对三种认知负荷下同时进行的 WM 表现的影响，以此来解决这些问题。在 1 mA（实验 1）或 2 mA（实验 2）强度下，将 tDCS 施加于左侧 DLPFC，而参与者则完成言语 n-回任务（1-、2-、3-回）。分析表明，tDCS 对 WM 没有总体影响，但与认知负荷有显著交互作用。本研究表明，认知负荷而不是 tDCS 强度可能是影响 WM 的决定性因素。此外，它强调需要对研究参数进行深入调查，以开发更有效的刺激方案。
