Department of Psychology, Guangdong Key Laboratory of Social Cognitive Neuroscience and Mental Health, Guangdong Provincial Key Laboratory of Brain Function and Disease, Sun Yat-Sen University, Guangzhou, 510006, China.
Department of Radiology, The 7th Medical Center of PLA General Hospital, Beijing, China.
Neuroimage. 2019 Nov 15;202:116068. doi: 10.1016/j.neuroimage.2019.116068. Epub 2019 Aug 7.
Thoughts of death substantially influence human behavior and psychological well-being. A large number of behavioral studies have shown evidence that asking individuals to think about death or mortality salience leads to significant changes of their behaviors. These findings support the well-known terror management theory to account for the psychological mechanisms of existential anxiety. However, despite increasing findings of mortality salience effects on human behavior, how the brain responds to reminders of mortality and changes the activity underlying subsequent behavior remains poorly understood. By scanning healthy adults (N = 80) of both sexes using functional magnetic resonance imaging, we showed that, relative to reading emotionally neutral sentences, reading sentences that evoke death-related thoughts decreased the salience network activity, reduced the connectivity between the cingulate cortex and other brain regions during a subsequent resting state, and dampened the speed of learning reward-related objects and cingulate responses to loss feedback during a subsequent reward learning task. In addition, the decreased resting-state cingulate connectivity mediated the association between salience network deactivations in response to reminders of mortality and suppressed cingulate responses to loss feedback. Finally, the suppressed cingulate responses to loss feedback further predicted the dampened speed of reward learning. Our findings demonstrate sequential modulations of the salience network activity by mortality salience, which provide a neural basis for understanding human behavior under mortality threat.
死亡的想法极大地影响了人类的行为和心理幸福感。大量行为研究表明，让个体思考死亡或死亡突显会导致其行为发生显著变化。这些发现支持了著名的恐惧管理理论，用以解释生存焦虑的心理机制。然而，尽管越来越多的研究表明死亡突显对人类行为有影响，但大脑如何对死亡的提醒做出反应并改变随后行为的活动仍然知之甚少。通过对 80 名健康的男女成年人进行功能性磁共振成像扫描，我们发现，与阅读引起情绪中性的句子相比，阅读唤起与死亡相关的想法的句子会降低突显网络的活动，减少在随后的静息状态中扣带回皮层与其他大脑区域之间的连接，并在随后的奖励学习任务中减缓对奖励相关物体的学习速度和扣带回对损失反馈的反应。此外，静息状态下扣带连接的减少介导了对死亡提醒的突显网络去激活与对损失反馈的扣带反应抑制之间的关联。最后，对损失反馈的扣带反应抑制进一步预测了奖励学习速度的减缓。我们的发现表明，死亡突显会对突显网络的活动进行连续的调节，为理解在死亡威胁下的人类行为提供了神经基础。
