Institute of Neuroscience and Centre for Behaviour and Evolution, Newcastle University, Henry Wellcome Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
School of Veterinary Science, University of Bristol, Bristol, UK.
Sci Rep. 2017 Nov 1;7(1):14832. doi: 10.1038/s41598-017-13776-4.
Early-life adversity is associated with increased vulnerability to depression in humans, and depression-like phenotypes in animals. However, different types of adverse experience may leave different signatures in adulthood. We experimentally manipulated the Amount of food delivered to European starling nestlings and the begging Effort required to obtain food during early development. Here, we report behavioural data in adulthood from a task that assessed sensitivity to shifts in reward magnitude characteristic of depression-like low mood. Birds that had experienced Hard Effort were more food motivated than birds that had experienced Easy Effort. Both Effort and Amount affected sensitivity to shifts in reward magnitude: Hard Effort birds showed an enhanced negative contrast effect following loss of reward ('disappointment'), and Lean Amount birds failed to show a normal positive contrast effect following gain in reward (a lack of 'elation'). Therefore, the feeding schedule experienced for just 10 days in early life caused enduring effects on feeding motivation and sensitivity to reward loss/gain consistent with human depression. Furthermore, the contrast effects were specific to different types of adversity. These results highlight the importance of early-life feeding schedules in the development of depression-like phenotypes.
早期生活逆境与人类易患抑郁症以及动物出现类似抑郁的表型有关。然而，不同类型的不良经历可能会在成年期留下不同的印记。我们通过实验操纵了欧洲椋鸟雏鸟在早期发育过程中获得食物的食物量和觅食努力程度。在这里，我们报告了一项评估对类似抑郁的情绪低落特征的奖赏幅度变化敏感性的任务的成年后行为数据。经历过艰苦努力的鸟类比经历过轻松努力的鸟类更有食物动机。努力程度和食物量都会影响对奖赏幅度变化的敏感性：在失去奖励后，艰苦努力的鸟类表现出增强的负对比效应（“失望”），而在获得奖励后，瘦弱的鸟类则没有表现出正常的正对比效应（“兴奋”）。因此，仅仅在生命早期经历 10 天的喂养时间表就会对进食动机和对奖赏损失/获得的敏感性产生持久影响，这与人类抑郁症一致。此外，对比效应是特定于不同类型的逆境的。这些结果强调了早期喂养时间表在类似抑郁表型发展中的重要性。
