Faraji Jamshid, Lehmann Hugo, Metz Gerlinde A, Sutherland Robert J
Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4.
Behav Brain Res. 2008 May 16;189(1):17-31. doi: 10.1016/j.bbr.2007.12.002. Epub 2007 Dec 15.
Spatial tasks are widely used to determine the function of limbic system structures in rats. The present study used a new task designed to evaluate spatial behavior, the ziggurat task (ZT), to examine the performance of rats with widespread hippocampal damage induced by N-methyl-d-aspartic acid (NMDA). The task consisted of an open field containing 16 identical ziggurats (pyramid shaped towers) arranged at equal distances. One of the ziggurats was baited with a food reward. The task required rats to navigate through the open field by using a combination of distal and/or proximal cues in order to locate the food reward. The ability to acquire and recall the location of the goal (baited) ziggurat was tested in consecutive training sessions of eight trials per day for 10 days. The location of the goal ziggurat was changed every second day, requiring the rats to learn a total of five different locations. Several parameters, including latency to find the target, distance traveled, the number of visits to non-baited ziggurats (errors), and the number of returns were used as indices of learning and memory. Control rats showed a significant decrease in distance traveled and reduced latency in locating the goal ziggurat across trials and days, suggesting that they learned and remembered the location of the goal ziggurat. Interestingly, the hippocampal-damaged group moved significantly faster, and traveled longer distances compared to the control group. Significant differences were observed between these groups with respect to the number of errors and returns on test days. Day 11 served as probe day, in which no food reward was given. The controls spent more time searching for the food in the previous training quadrant compared to the hippocampal group. The findings demonstrate that the ZT is a sensitive and efficient dry task for measuring hippocampus-dependent spatial performance in rats requiring little training and not associated with some of the disadvantages of water tasks.
空间任务被广泛用于确定大鼠边缘系统结构的功能。本研究使用了一种旨在评估空间行为的新任务——金字塔任务（ZT），以检验由N-甲基-D-天冬氨酸（NMDA）诱导的广泛性海马损伤大鼠的表现。该任务包括一个开放场地，其中有16个等距排列的相同金字塔（金字塔形状的塔）。其中一个金字塔放置了食物奖励。该任务要求大鼠通过使用远端和/或近端线索的组合在开放场地中导航，以找到食物奖励。在连续10天每天进行8次试验的训练过程中，测试大鼠获取和回忆目标（放置诱饵的）金字塔位置的能力。目标金字塔的位置每隔一天改变一次，要求大鼠总共学习五个不同的位置。几个参数，包括找到目标的潜伏期、行进距离、对未放置诱饵的金字塔的访问次数（错误）和返回次数，被用作学习和记忆的指标。对照大鼠在各试验和各天中，找到目标金字塔的行进距离显著减少，潜伏期缩短，这表明它们学习并记住了目标金字塔的位置。有趣的是，与对照组相比，海马损伤组移动速度明显更快，行进距离更长。在测试日，这些组在错误次数和返回次数方面存在显著差异。第11天作为探测日，当天不给食物奖励。与海马损伤组相比，对照组在之前训练象限中花费更多时间寻找食物。研究结果表明，ZT是一种灵敏且高效的非水任务，用于测量大鼠依赖海马体的空间表现，所需训练少，且不存在一些水任务的缺点。
