Abstract：
BACKGROUND: Fear extinction is a fundamental component of exposure-based therapies for anxiety-related disorders. The renewal of fear in a different context after extinction highlights the importance of contextual factors. In this study, we aimed to investigate the causal role of the left inferior frontal gyrus (LiFG) in the context-dependency of fear extinction learning via administration of transcranial direct current stimulation (tDCS) over this area.
METHODS: 180 healthy subjects were assigned to 9 groups: 3 tDCS conditions (anodal, cathodal, and sham) × 3 context combinations (AAA, ABA, and ABB). The fear conditioning/extinction task was conducted over three consecutive days: acquisition, extinction learning, and extinction recall. tDCS (2 mA, 10min) was administered during the extinction learning phase over the LiFG via a 4-electrode montage. Skin conductance response (SCR) data and self-report assessments were collected.
RESULTS: During the extinction learning phase, groups with excitability-enhancing anodal tDCS showed a significantly higher fear response to the threat cues compared to cathodal and sham stimulation conditions, irrespective of contextual factors. This effect was stable until the extinction recall phase. Additionally, excitability-reducing cathodal tDCS caused a significant decrease of the response difference between the threat and safety cues during the extinction recall phase. The self-report assessments showed no significant differences between the conditions throughout the experiment.
CONCLUSIONS: Independent of the context, excitability enhancement of the LiFG did impair fear extinction, and led to preservation of fear memory. In contrast, excitability reduction of this area enhanced fear extinction retention. These findings imply that the LiFG plays a role in the fear extinction network, which seems to be however context-independent.
METHODS: 180 healthy subjects were assigned to 9 groups: 3 tDCS conditions (anodal, cathodal, and sham) × 3 context combinations (AAA, ABA, and ABB). The fear conditioning/extinction task was conducted over three consecutive days: acquisition, extinction learning, and extinction recall. tDCS (2 mA, 10min) was administered during the extinction learning phase over the LiFG via a 4-electrode montage. Skin conductance response (SCR) data and self-report assessments were collected.
RESULTS: During the extinction learning phase, groups with excitability-enhancing anodal tDCS showed a significantly higher fear response to the threat cues compared to cathodal and sham stimulation conditions, irrespective of contextual factors. This effect was stable until the extinction recall phase. Additionally, excitability-reducing cathodal tDCS caused a significant decrease of the response difference between the threat and safety cues during the extinction recall phase. The self-report assessments showed no significant differences between the conditions throughout the experiment.
CONCLUSIONS: Independent of the context, excitability enhancement of the LiFG did impair fear extinction, and led to preservation of fear memory. In contrast, excitability reduction of this area enhanced fear extinction retention. These findings imply that the LiFG plays a role in the fear extinction network, which seems to be however context-independent.
摘要：
背景：恐惧消退是焦虑相关障碍的基于暴露疗法的基本组成部分。灭绝后在不同背景下的恐惧更新凸显了背景因素的重要性。在这项研究中,我们旨在研究左额下回(LiFG)在通过经颅直流电刺激(tDCS)进行恐惧消退学习的情境依赖性中的因果作用.
方法：将180名健康受试者分为9组：3tDCS条件（阳极，Cathodal,和假）×3个上下文组合（AAA，ABA,和ABB）。恐惧调节/灭绝任务连续三天进行：获取，灭绝学习，和灭绝召回。tDCS(2mA,在熄灭学习阶段，通过4电极蒙太奇在LiFG上施用10分钟）。收集皮肤电导反应（SCR）数据和自我报告评估。
结果：在消光学习阶段，与阴极和假刺激条件相比，具有兴奋性增强阳极tDCS的组显示出对威胁线索的恐惧反应显着提高。无论上下文因素如何。这种效果是稳定的，直到灭绝召回阶段。此外,在灭绝召回阶段，降低兴奋性的阴极tDCS导致威胁和安全线索之间的响应差异显着降低。自我报告评估显示在整个实验中条件之间没有显著差异。
结论：独立于上下文，LiFG的兴奋性增强确实损害了恐惧灭绝，并导致了恐惧记忆的保存。相比之下,该区域的兴奋性降低增强了恐惧灭绝的保留。这些发现暗示LiFG在恐惧灭绝网络中发挥作用，这似乎是与上下文无关的。
方法：将180名健康受试者分为9组：3tDCS条件（阳极，Cathodal,和假）×3个上下文组合（AAA，ABA,和ABB）。恐惧调节/灭绝任务连续三天进行：获取，灭绝学习，和灭绝召回。tDCS(2mA,在熄灭学习阶段，通过4电极蒙太奇在LiFG上施用10分钟）。收集皮肤电导反应（SCR）数据和自我报告评估。
结果：在消光学习阶段，与阴极和假刺激条件相比，具有兴奋性增强阳极tDCS的组显示出对威胁线索的恐惧反应显着提高。无论上下文因素如何。这种效果是稳定的，直到灭绝召回阶段。此外,在灭绝召回阶段，降低兴奋性的阴极tDCS导致威胁和安全线索之间的响应差异显着降低。自我报告评估显示在整个实验中条件之间没有显著差异。
结论：独立于上下文，LiFG的兴奋性增强确实损害了恐惧灭绝，并导致了恐惧记忆的保存。相比之下,该区域的兴奋性降低增强了恐惧灭绝的保留。这些发现暗示LiFG在恐惧灭绝网络中发挥作用，这似乎是与上下文无关的。
