CAA: Comparative Studies of Spatial and Nonspatial Memory inMammals

海马体是一种调节空间学习的大脑结构，其大小与野生啮齿动物的空间行为有关。在这个职业发展奖项中，我们将比较不同物种在抽象学习任务上的空间学习能力。使用操作方法，将对海马大小不同的物种进行比较，比较两项已知涉及海马体的操作任务（空间延迟-非匹配样本，同时气味识别）和两项不需要完整海马体的任务（听觉识别，连续嗅觉识别）。将比较两种袋鼠大鼠（Dipodomys）和两种田鼠（Microtus）。我们预测，在每个属中，海马较大的物种在海马任务，特别是空间任务上表现出更强的学习能力，但在非海马任务上不存在物种差异。由于几个原因，拟议的研究将是重要的。这将是对野生啮齿动物不同类型记忆的首次比较研究。因为我们对哺乳动物记忆生理学的理解很大程度上是基于实验室老鼠的，所以了解实验室老鼠是否表现出典型的啮齿动物行为是很重要的。更重要的是，对近亲啮齿类动物的比较研究可以确定物种栖息地的哪些特征会导致学习和记忆能力的增加。这项研究不仅可以帮助我们了解动物记忆的进化，还可以帮助我们了解海马体，这是一个对动物和人类记忆都至关重要的结构。例如，没有其他动物研究试图比较涉及海马体的不同任务的表现（迷宫学习，气味辨别）。因此，这项研究不仅揭示了记忆的进化，而且揭示了海马体的功能，这是一个具有临床重要性的结构。

The size of the hippocampus, a brain structure known to mediate spatial learning, is correlated with spatial behavior in wild rodents. In this career advancement award, a comparison will be made of the spatial learning ability of different species on abstract learning tasks. Using operant methods, pairs of species, known to differ in hippocampal size, will be compared on two operant tasks known to involve the hippocampus (spatial delayed- nonmatch-to-sample, simultaneous odor discrimination) and two tasks that do not require an intact hippocampus (auditory discrimination, successive olfactory discrimination). Two species of kangaroo rats (Dipodomys) and two species of voles (Microtus) will be compared. It is predicted that, within each genus, the species with a larger hippocampus will show superior learning ability on hippocampal tasks, particularly the spatial task, but that there should be no species differences on nonhippocampal tasks. The proposed study will be significant for several reasons. It will be the first comparative study of different types of memory in wild rodents. Because our understanding of the physiology of memory in mammals is largely based on the laboratory rat, it is important to know if laboratory rats show typical rodent behavior. More importantly, comparative studies of closely related rodent species can identify what features of a species's habitat can lead to increases in learning and memory capacity. Not only can this study help us to understand the evolution of animal memory, but it can also help us to understand the hippocampus, a structure critical in both animal and human memory. For example, no other animal study has attempted to compare performance of different tasks involving the hippocampus (maze learning, odor discrimination). Thus, this study will shed light not only on the evolution of memory, but on the function of the hippocampus, a structure of clinical importance.