Department of Psychology, University of Toronto Mississauga, Ontario, Canada.
Behav Brain Res. 2012 Aug 1;233(2):415-21. doi: 10.1016/j.bbr.2012.05.024. Epub 2012 May 23.
The zebrafish may be an ideal tool with which genes underlying learning and memory can be identified and functionally investigated. From a translational viewpoint, relational learning and episodic memory are particularly important as their impairment is the hallmark of prevalent human neurodegenerative diseases. Recent reports suggest that zebrafish are capable of solving complex relational-type associative learning tasks, namely spatial learning tasks. However, it is not known whether good performance in these tasks was truly based upon relational learning or upon a single CS-US association. Here we study whether zebrafish can find a rewarding stimulus (sight of conspecifics) based upon a single associative cue or/and upon the location of the reward using a method conceptually similar to 'context and cue dependent fear conditioning' employed with rodents. Our results confirm that zebrafish can form an association between a salient visual cue and the rewarding stimulus and at the same time they can also learn where the reward is presented. Although our results do not prove that zebrafish form a dynamic spatial map of their surroundings and use this map to locate their reward, they do show that these fish perform similarly to rodents whose hippocampal function is unimpaired. These results further strengthen the notion that complex cognitive abilities exist in the zebrafish and thus they may be analyzed using the excellent genetic tool set developed for this simple vertebrate.
斑马鱼可能是一种理想的工具，可以用来鉴定和研究学习和记忆相关的基因。从转化医学的角度来看，关系学习和情景记忆尤为重要，因为它们的损伤是常见人类神经退行性疾病的标志。最近的报告表明，斑马鱼能够解决复杂的关系型联想学习任务，即空间学习任务。然而，尚不清楚它们在这些任务中的良好表现是否真的基于关系学习，或者是基于单一的 CS-US 关联。在这里，我们使用一种与啮齿动物“上下文和线索依赖性恐惧条件反射”类似的方法，研究斑马鱼是否可以基于单一的联想线索和奖励刺激的位置来寻找奖励刺激（同类的视觉）。我们的结果证实，斑马鱼可以将一个显著的视觉线索与奖励刺激联系起来，同时也可以学习到奖励的位置。虽然我们的结果并不能证明斑马鱼形成了其周围环境的动态空间地图，并使用该地图来定位奖励，但它们确实表明这些鱼的表现与海马功能未受损的啮齿动物相似。这些结果进一步加强了这样一种观点，即复杂的认知能力存在于斑马鱼中，因此可以使用为这种简单的脊椎动物开发的优秀遗传工具来分析这些能力。
