奖赏预测误差对记忆辨别的影响:行为及眼动的证据

记忆辨别反映了个体对所经历事件能够形成独特的记忆表征并正确拒斥相似诱饵的能力,是情景记忆最重要的特征之一。研究采用奖赏条件学习范式和记忆相似任务考察奖赏预测误差对记忆辨别的影响。结果显示奖赏预测误差的绝对值越大,记忆辨别值越高;在诱饵击中项目中,高奖赏预测误差绝对值条件下的瞳孔扩张值(pupil dilation,PD)显著高于低绝对值条件;而在诱饵虚报项目中,两者无显著差异;瞳孔扩张值是记忆辨别的正向预测因子。综上,不带符号的奖赏预测误差能够引发个体的意外反应、提高其情绪唤醒水平(瞳孔扩张)、促进个体对细节信息的加工、提高记忆辨别。

Role of Specific Synaptic Plasticity Interfering Peptides in the Expression of Morphine Induced Conditioned Place Preference in Mice

Learned association between context and drug abuse is essential for the drug conditioned place preference （CPP）, which is an animal model widely used to measure drug reward. Synaptic plasticity, in the form of long-term potentiation （LTP） and depression （LTD）, is regarded as a proposed cellular substrate of learning and memory. However, the exact role of LTP/LTD in addiction is not known yet. Therefore, by bioinformatics we designed peptides aiming to interfere with LTP and LTD respectively, to study their individual role in the expression of morphine CPP. We found that the interfering peptide Pep-A2 can specifically block hippocampal LTP in CA1 region, whereas Pep-A3 can block LTD in this region. Treatment of either of their cell penetrating forms （Tat-A2 or Tat-A3） before test can block the expression of Morphine CPP in mice. These results suggested that both LTP and LTD are required in the drug-associated learning and memory.

蜜蜂对复合气味中特征因素的选择性记忆巩固的研究

目的 蜜蜂天生具有丰富的嗅觉辨识能力,觅食、交配、导航以及社交活动均依赖其嗅觉系统,是研究嗅觉感知和学习记忆的行为及神经机制的理想模型。蜜蜂既能够将某个复合气味作为一个整体也可以将复合气味的各组成成分进行辨别和区分,但是在特征依赖的联合记忆中依据何种原则进行加工并存储到长期记忆还不清楚。方法 本文利用特征阳性(feature positive:AB+,B-)和特征阴性(feature negative:AB-,B+)的奖赏性嗅觉条件化,训练蜜蜂对复合气味和成分气味的辨别,并检测蜜蜂对复合气味(AB)、成分气味(B)以及特征气味(A)的中长时记忆(3 h)和长时记忆(24 h)。结果 在特征阳性的奖赏性嗅觉条件化中,蜜蜂对训练过的气味可以形成稳定的中长时和长时记忆,并且对复合气味中的特征气味的记忆与复合气味的记忆呈现高度相似。但在特征阴性的奖赏性嗅觉条件化中,蜜蜂虽能够在3 h和24 h对训练过的两种气味具有显著的伸喙反应差异,且对特征阴性的气味无显著反应,但对复合气味的反应随时间的推移而增加。结论 实验结果表明,蜜蜂选择性地将与奖赏信息联合出现的气味巩固到长时记忆中,但并未依据特征成分加工储存到长时记忆中。奖赏信息预示着食物源,与生存息息相关,表明对环境信息进行选择性的记忆巩固加工并储存可能是低等动物高效地编码生存相关信息的重要策略。