首页分享背外侧前额叶在安慰剂效应中的作用：社会情绪调节研究

背外侧前额叶在安慰剂效应中的作用：社会情绪调节研究

来源：花匠小妙招时间：2024-11-25 10:39

摘要：

为考察安慰剂效应在情绪调节中的脑机制, 本研究以社会排斥图片为情绪诱发材料诱发社会疼痛, 采用经颅磁刺激技术(transcranial magnetic stimulation, TMS)激活背外侧前额叶(dorsolateral prefrontal cortex, DLPFC), 并使用事件相关电位观测TMS对安慰剂下调社会疼痛的影响。实验以“TMS组别” (DLPFC组、控制组)为被试间变量, “安慰剂条件” (安慰剂、非安慰剂)为被试内因素。结果发现, DLPFC组(n = 50)比控制组(n = 50)在安慰剂条件下报告的负性情绪更弱, 反映情绪体验强度的晚正成分的波幅也更低, 上述组间差异在非安慰剂条件不显著。结果还表明, DLPFC组比控制组更相信安慰剂的效果, 愿意花更多的钱来购买安慰剂。此外相关结果发现, 由DLPFC激活导致的安慰剂效应增强可有效降低社交焦虑倾向被试的负性社会情绪。本研究是结合脑调控和脑观测技术探讨安慰剂情绪调节脑机制的首次尝试, 研究发现不但揭示了DLPFC在安慰剂调节情绪过程中的重要因果作用, 还为临床治疗以情绪失调为主要症状的抑郁焦虑等精神障碍患者提供了脑调控干预的可行性脑靶点。

关键词: 背外侧前额叶, 安慰剂效应, 社会疼痛, 社会排斥, 情绪调节, 经颅磁刺激

Abstract:

Under the influence of the novel coronavirus epidemic, some negative social events, such as separation of family or friends and home isolation have increased. These events can cause negative emotion experiences similar to physical pain, thus they are called social pain. Placebo effect refers to the positive response to the inert treatment with no specific therapeutic properties, which has been shown to be one of the effective ways to alleviate social pain. Studies have shown that the dorsolateral prefrontal cortex (DLPFC) plays a key role in placebo effect. Therefore, this study aimed to explore whether activating DLPFC by using transcranial magnetic stimulation (TMS) could improve the ability of placebo effects to regulate social pain. Besides, we also combined neuroimaging and neuromodulation techniques to provide bidirectional evidence for the role of the DLPFC on placebo effects.

We recruited a total of 100 participants to finish the task of negative emotional rating of the social exclusion images. Among them, 50 participants were stimulated by TMS at the right DLPFC (rDLPFC), while the others were assigned to the sham group. This study contained two independent variables. The between- subject variable was TMS group(rDLPFC-activated group or sham group) and the within-subject variable was placebo type (no-placebo and placebo). All participants received nasal spray in two blocks. In the no-placebo condition, participants were instructed that they would receive a saline nasal spray which helped to improve physiological readings; in placebo block, participants were told to administrate an intranasal fluoxetine spray (saline nasal spray in fact) that could reduce unpleasantness within 10 minutes. To strengthen the expectation of intranasal fluoxetine, participants viewed a professional introduction to fluoxetine’s clinical and academic usage including downregulating negative emotion, such as fear, anxiety, and disgust. Participants who received the placebo block first would be reminded that fluoxetine’s effect was over before the next block to reduce the carry-over for the following block. Self-reported negative emotional and electroencephalogram data were recorded.

There was a significant two-way interaction of TMS group and placebo type. Results showed that compared with the sham group, participants in the rDLPFC-activated group reported less negative emotional feeling and had a lower amplitude of the late positive potential (LPP) in placebo condition, a component that reflects the emotional intensity, suggesting that activating rDLPFC can improve the ability of placebo effect to regulate social pain.

The above finding suggested that activating DLPFC can improve the placebo effect of regulating negative emotion. Moreover, this study is the first attempt to investigate the enhancement of placebo effects by using TMS on emotion regulation. The findings not only support the critical role of DLPFC on placebo effect using neuroimaging and neuromodulation techniques, but also provide a potential brain target for treating emotional regulation deficits in patients with psychiatric disorders.

Key words: dorsolateral prefrontal cortex, placebo effect, social pain, social exclusion, emotion regulation, transcranial magnetic stimulation

中图分类号:

B845

R395