Slaney Chloe, Hinchcliffe Justyna K, Robinson Emma S J
School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, UK.
Curr Top Behav Neurosci. 2018;40:169-193. doi: 10.1007/7854_2018_44.
Understanding the neurobiology of major depressive disorder (MDD) remains one of the major challenges in neuroscience. The disease is heterogeneous in nature, and patients present with a varied symptom profile. Studies seeking to identify biomarkers for MDD diagnosis and treatment have not yet found any one candidate which achieves sufficient sensitivity and specificity. In this article, we consider whether neuropsychological impairments, specifically affective biases, could provide a behavioural biomarker. Affective biases are observed when emotional states influence cognitive function. These biases have been shown to influence a number of different cognitive domains with some specific deficits observed in MDD. It has also been possible to use these neuropsychological tests to inform the development of translational tasks for non-human species. The results from studies in rodents suggest that quantification of affective biases is feasible and may provide a reliable method to predict antidepressant efficacy as well as pro-depressant risk. Animal studies suggest that affective state-induced biases in learning and memory operate over a different time course to biases influencing decision-making. The implications for these differences in terms of task validity and future ideas relating to affective biases and MDD are discussed. We also describe our most recent studies which have shown that depression-like phenotypes share a common deficit in reward-related learning and memory which we refer to as a reward-induced positive bias. This deficit is dissociable from more typical measures of hedonic behaviour and motivation for reward and may represent an important and distinct form of reward deficit linked to MDD.
理解重度抑郁症（MDD）的神经生物学机制仍然是神经科学领域的主要挑战之一。这种疾病本质上具有异质性，患者表现出各种各样的症状。旨在确定MDD诊断和治疗生物标志物的研究尚未找到任何一种能达到足够敏感性和特异性的候选标志物。在本文中，我们探讨神经心理学损伤，特别是情感偏差，是否能提供一种行为生物标志物。当情绪状态影响认知功能时，就会观察到情感偏差。这些偏差已被证明会影响许多不同的认知领域，在MDD中还观察到了一些特定的缺陷。利用这些神经心理学测试来指导非人类物种的转化任务开发也成为可能。啮齿动物研究结果表明，量化情感偏差是可行的，并且可能提供一种可靠的方法来预测抗抑郁疗效以及促抑郁风险。动物研究表明，情感状态诱发的学习和记忆偏差与影响决策的偏差在不同的时间进程中起作用。本文讨论了这些差异在任务有效性方面的意义以及与情感偏差和MDD相关的未来设想。我们还描述了我们最近的研究，这些研究表明，类似抑郁的表型在与奖励相关的学习和记忆方面存在共同缺陷，我们将其称为奖励诱发的正偏差。这种缺陷与享乐行为和奖励动机的更典型测量方法不同，可能代表了一种与MDD相关的重要且独特的奖励缺陷形式。
