Collett T S, Cartwright B A, Smith B A
J Comp Physiol A. 1986 Jun;158(6):835-51. doi: 10.1007/BF01324825.
The aim of this study is to understand what a rodent (Meriones unguiculatus) learns about the geometrical relations between a goal and nearby visual landmarks and how it uses this information to reach a goal. Gerbils were trained to find sunflower seeds on the floor of a light-tight, black painted room illuminated by a single light bulb hung from the ceiling. The position of the seed on the floor was specified by an array of one or more landmarks. Once training was complete, we recorded where the gerbils searched when landmarks were present but the seed was absent. In such tests, gerbils were confronted either with the array of landmarks to which they were accustomed or with a transformation of this array. Animals searched in the appropriate spot when trained to find seeds placed in a constant direction and at a constant distance from a single cylindrical landmark. Since gerbils look in one spot and not in a circle centred on the landmark, the direction between landmark and goal must be supplied by cues external to the landmark array. Distance, on the other hand, must be measured with respect to the landmark. Tests in which the size of the landmark was altered from that used in training suggest that distance is not learned solely in terms of the apparent size of the landmark as seen from the goal. Gerbils can still reach a goal defined by an array of landmarks when the room light is extinguished during their approach. This ability implies that they have already planned a trajectory to the goal before the room is darkened. In order to compute such a trajectory, their internal representation of landmarks and goal needs to contain information about the distances and bearings between landmarks and goal. For planning trajectories, each landmark of an array can be used separately from the others. Gerbils trained to a goal specified by an array of several landmarks were tested with one or more of the landmarks removed or with the array expanded. They then searched as though they had computed an independent trajectory for each landmark. For instance, gerbils trained with an array of two landmarks were tested with the distance between two landmarks doubled. The animals then searched for seeds in two positions, which were at the correct distance and in the right direction from each landmark.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究的目的是了解啮齿动物（长爪沙鼠）如何学习目标与附近视觉地标之间的几何关系，以及它如何利用这些信息到达目标。沙鼠在一个光线昏暗、漆成黑色的房间地面上接受训练，寻找由天花板上悬挂的单个灯泡照亮的葵花籽。种子在地面上的位置由一个或多个地标阵列指定。训练完成后，我们记录了在地标存在但种子不存在时沙鼠的搜索位置。在这类测试中，沙鼠面对的要么是它们习惯的地标阵列，要么是该阵列的变换形式。当训练沙鼠找到放置在与单个圆柱形地标保持恒定方向和恒定距离处的种子时，它们会在合适的位置进行搜索。由于沙鼠看向一个特定地点而非以地标为中心的圆圈，地标与目标之间的方向必须由地标阵列之外的线索提供。另一方面，距离必须相对于地标进行测量。改变地标大小的测试表明，距离并非仅依据从目标处看到的地标表观大小来学习。当房间灯光在沙鼠接近目标时熄灭，它们仍能到达由地标阵列定义的目标。这种能力意味着它们在房间变暗之前就已经规划好了通往目标的轨迹。为了计算这样的轨迹，它们脑海中地标和目标的内部表征需要包含地标与目标之间距离和方位的信息。为了规划轨迹，阵列中的每个地标都可以与其他地标分开使用。对经过训练以由几个地标组成的阵列指定的目标的沙鼠进行测试，移除其中一个或多个地标，或者扩展该阵列。然后它们的搜索方式就好像为每个地标都计算了一条独立的轨迹。例如，用由两个地标组成的阵列训练的沙鼠，在两个地标之间的距离加倍后接受测试。然后这些动物会在两个位置寻找种子，这两个位置与每个地标之间的距离和方向都是正确的。（摘要截断于400字）
