睡眠对恐惧学习的影响及其认知神经机制

The effect of sleep on fear learning and its cognitive neural mechanisms

睡眠问题可能会诱发恐惧相关情绪障碍(焦虑、创伤性应激障碍、恐怖症等),研究睡眠影响恐惧学习的认知神经机制,有助于增强对恐惧相关情绪障碍的预测、诊断和治疗。以往研究表明睡眠剥夺影响恐惧习得和消退主要是通过抑制vmPFC活动,阻碍其与杏仁核的功能连接,从而导致恐惧习得增强或是消退学习受损。进一步研究发现睡眠不同阶段对恐惧学习相关脑区有独特的影响:剥夺(缺乏)快速眼动睡眠会抑制vmPFC活动、增强杏仁核、海马激活,导致恐惧习得增强,消退学习受损,此外边缘皮层的功能连接减少破坏了记忆巩固(恐惧记忆和消退记忆);而慢波睡眠主要与海马变化有关,慢波睡眠期间进行目标记忆重激活可促进恐惧消退学习。未来研究需要增加睡眠影响恐惧泛化的神经机制研究、及昼夜节律中断对恐惧消退的影响,以及关注动物睡眠研究向人类睡眠研究转化中存在的问题。

Sleep problems may induce fear-related mood disorders such as anxiety,post-traumatic stress disorder(PTSD),and phobias,among others.Studying the cognitive and neural mechanisms involved in the relationship between sleep problems and fear learning can help enhance the prediction,diagnosis,and treatment of fear-related mood disorders.Previous studies have shown that sleep deprivation affects fear acquisition and extinction mainly by inhibiting the activity of the ventral medial prefrontal cortex(vmPFC)and blocking its functional connections with the amygdala,resulting in impaired safe learning that fails to inhibit fear of threatening stimuli,thus enhancing fear acquisition or impaired of extinction.Further studies have reported that different stages of sleep have distinct effects on brain regions associated with fear learning;in particular,rapid eye movement(REM)sleep deprivation(insufficient)and complete sleep deprivation have similar effects on the cognitive and neural mechanisms of fear learning.Deprivation of REM sleep suppresses vmPFC activity,enhances amygdala activation,and thus enhances fear acquisition.In addition,reduced functional connectivity in the limbic cortex disrupts fear memory consolidation.In contrast,the slow-wave sleep(SWS)stage facilitates fear extinction learning through target memory reactivation,which allows the hippocampus to re-code threatening stimuli and accelerate the consolidation of new safety information in the amygdala.Future research should be conducted to further the study of the neural mechanisms by which sleep affects fear generalization and the effect of circadian rhythm disruption on fear extinction,as well as clarifying the problems in the translation of animal sleep studies to human sleep studies.