急性应激通过腹外侧纹状体中的多巴胺信号增强联想学习。

Acute Stress Enhances Associative Learning via Dopamine Signaling in the Ventral Lateral Striatum.

机构信息

Neurosciences Institute and Department of Biology, University of Texas at San Antonio, San Antonio, Texas 78249.

Neurosciences Institute and Department of Biology, University of Texas at San Antonio, San Antonio, Texas 78249

出版信息

J Neurosci. 2020 May 27;40(22):4391-4400. doi: 10.1523/JNEUROSCI.3003-19.2020. Epub 2020 Apr 22.

Abstract

Acute stress transiently increases vigilance, enhancing the detection of salient stimuli in one's environment. This increased perceptual sensitivity is thought to promote the association of rewarding outcomes with relevant cues. The mesolimbic dopamine system is critical for learning cue-reward associations. Dopamine levels in the ventral striatum are elevated following exposure to stress. Together, this suggests that the mesolimbic dopamine system could mediate the influence of acute stress on cue-reward learning. To address this possibility, we examined how a single stressful experience influenced learning in an appetitive pavlovian conditioning task. Male rats underwent an episode of restraint prior to the first conditioning session. This acute stress treatment augmented conditioned responding in subsequent sessions. Voltammetry recordings of mesolimbic dopamine levels demonstrated that acute stress selectively increased reward-evoked dopamine release in the ventral lateral striatum (VLS), but not in the ventral medial striatum. Antagonizing dopamine receptors in the VLS blocked the stress-induced enhancement of conditioned responding. Collectively, these findings illustrate that stress engages dopamine signaling in the VLS to facilitate appetitive learning. Acute stress influences learning about aversive and rewarding outcomes. Dopamine neurons are sensitive to stress and critical for reward learning. However, it is unclear whether stress regulates reward learning via dopamine signaling. Using fast-scan cyclic voltammetry as rats underwent pavlovian conditioning, we demonstrate that a single stressful experience increases reward-evoked dopamine release in the ventral lateral striatum. This enhanced dopamine signal accompanies a long-lasting increase in conditioned behavioral responding. These findings highlight that the ventral lateral striatum is a node for mediating the effect of stress on reward processing.

摘要

急性应激会短暂增加警觉性,提高对环境中显著刺激的检测能力。这种增强的感知敏感性被认为促进了奖励结果与相关线索的关联。中脑边缘多巴胺系统对于学习线索-奖励关联至关重要。暴露于应激后,腹侧纹状体中的多巴胺水平升高。综上所述,这表明中脑边缘多巴胺系统可能介导了急性应激对线索-奖励学习的影响。为了研究这种可能性,我们检查了单次应激体验如何影响奖赏性巴甫洛夫条件反射任务中的学习。雄性大鼠在第一次条件反射训练前经历了一段束缚期。这种急性应激处理增强了随后训练中的条件反应。中脑边缘多巴胺水平的伏安法记录表明,急性应激选择性地增加了腹侧外侧纹状体(VLS)中奖励诱发的多巴胺释放,但在腹侧内侧纹状体中没有增加。VLS 中的多巴胺受体拮抗剂阻断了应激引起的条件反应增强。总的来说,这些发现表明,应激通过 VLS 中的多巴胺信号促进了奖赏性学习。急性应激影响对奖赏和惩罚结果的学习。多巴胺神经元对应激敏感,对奖励学习至关重要。然而,尚不清楚应激是否通过多巴胺信号调节奖励学习。当大鼠进行巴甫洛夫条件反射训练时,我们使用快速扫描循环伏安法证明,单次应激体验会增加腹侧外侧纹状体中奖励诱发的多巴胺释放。这种增强的多巴胺信号伴随着持久的条件行为反应增强。这些发现强调了腹侧外侧纹状体是介导应激对奖励处理影响的一个节点。

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