Data file from Dopamine D1 receptor activation leads to object recognition memory in a coral reef fish

Object recognition memory is the ability to identify previously seen objects and is an adaptive mechanism that increases survival for many species throughout the animal kingdom. Previously believed to be possessed by only the highest order mammals, it is now becoming clear that fish are also capable of this type of memory formation. Similar to the mammalian hippocampus, the dorsolateral pallium regulates distinct memory processes and is modulated by neurotransmitters such as dopamine. Caribbean bicolour damselfish (<i>Stegastes partitus</i>) live in complex environments dominated by coral reef structures and thus likely possess many types of complex memory abilities including object recognition. This study used a novel object recognition test in which fish were first presented two identical objects, then after a retention interval of 10 min with no objects, the fish were presented with a novel object and one of the objects they had previously encountered in the first trial. We demonstrate that the dopamine D₁-receptor agonist (SKF 38393) induces the formation of object recognition memories in these fish. Thus, our results suggest that dopamine-receptor mediated enhancement of spatial memory formation in fish represents an evolutionarily conserved mechanism in vertebrates.

物体识别记忆（object recognition memory）是指识别既往所见物体的能力，亦是提升动物界诸多物种生存概率的适应性机制。此前学界曾认为该能力仅为高等哺乳动物所独有，如今已有研究明确，鱼类同样具备此类记忆的形成能力。与哺乳动物的海马体（hippocampus）类似，背外侧脑皮层（dorsolateral pallium）可调控特异性记忆过程，并受多巴胺等神经递质的调节。加勒比双色雀鲷（*Stegastes partitus*）栖息于以珊瑚礁结构为主的复杂生境中，因此极有可能具备包括物体识别记忆在内的多种复杂记忆能力。本研究采用新颖物体识别实验范式：首先向受试鱼类呈现两件完全相同的物体，随后设置10分钟的记忆保持间隔期（期间无任何物体呈现），最后向鱼类同时展示一件全新物体与首次实验中出现过的其中一件旧物体。本研究证实，多巴胺D₁受体激动剂（SKF 38393）可诱导此类鱼类形成物体识别记忆。综上，本研究结果表明，鱼类体内由多巴胺受体介导的空间记忆形成增强效应，代表了脊椎动物中一种进化保守的机制。