Proaction Laboratory, Faculty of Psychology and Educational Sciences, University of Coimbra, 3001-802, Coimbra, Portugal.
Center for Research in Neuropsychology and Cognitive Behavioral Intervention - CINEICC of the Faculty of Psychology and Educational Sciences, University of Coimbra, Rua do Colégio Novo, 3000-115, Coimbra, Portugal.
Exp Brain Res. 2022 Jan;240(1):221-235. doi: 10.1007/s00221-021-06248-9. Epub 2021 Oct 25.
Transcranial direct current stimulation (tDCS) has been studied to enhance extinction-based treatments for anxiety disorders. However, the field shows conflicting results about its anxiolytic effect and only a few studies have observed the extinction of consolidated memories. We looked to study the effect of offline 1 mA tDCS over the right dorsolateral pre-frontal cortex across the fear pathways, in consolidated fear response during delayed extinction. Participants (N = 34 women) underwent in a two-day fear conditioning procedure. On day 1, participants were assigned to the control group (N = 18) or the tDCS group (N = 16) and went through a fear acquisition procedure. On day 2, the tDCS group received 20 min tDCS before extinction and while inside the MRI scanner. The control group completed the extinction procedure only. The tDCS session (for the tDCS group) and the fMRI scan (for both groups) were completed just on the second day. Univariate fMRI analysis showed stimulation-dependent activity during late extinction with the tDCS group showing decreased neural activity during the processing of threat cues (CS +) and increased activity during the processing of safety cues (CS -), in prefrontal, postcentral and paracentral regions, during late extinction. ROI to whole-brain psychophysiological interaction (PPI) analysis showed the tDCS effect on the connectivity between the left dorsolateral prefrontal cortex three cortical-amygdalo-hippocampal-cerebellar pathway clusters during the processing of the CS + in late extinction (TFCE corrected; p < 0.05). Increased neuronal activity during the processing of safety cues and stronger coupling during the processing of threat cues might be the mechanisms by which tDCS contributes to stimuli discrimination.
经颅直流电刺激（tDCS）已被用于增强基于消退的焦虑障碍治疗方法。然而，该领域关于其抗焦虑效果的结果存在矛盾，只有少数研究观察到了巩固记忆的消退。我们研究了在延迟消退期间，对恐惧通路中右侧背外侧前额皮质进行离线 1 mA tDCS 对巩固的恐惧反应的影响。参与者（N=34 名女性）进行了为期两天的恐惧条件反射程序。在第 1 天，参与者被分配到对照组（N=18）或 tDCS 组（N=16），并经历了恐惧获得程序。在第 2 天，tDCS 组在消退前和 MRI 扫描仪内接受 20 分钟 tDCS。对照组仅完成消退程序。tDCS 疗程（tDCS 组）和 fMRI 扫描（两组）都仅在第 2 天完成。单变量 fMRI 分析显示，在消退后期，刺激依赖性活动与 tDCS 组在处理威胁线索（CS+）时的神经活动减少和处理安全线索（CS-）时的神经活动增加有关，在前额叶、后中央和旁中央区域。ROI 到全脑心理生理交互（PPI）分析显示，tDCS 对左背外侧前额皮质在处理 CS+时与三个皮质杏仁核海马小脑通路簇之间的连通性的影响在消退后期（TFCE 校正；p<0.05）。处理安全线索时神经元活动增加和处理威胁线索时耦合增强可能是 tDCS 有助于刺激辨别力的机制。
