Rice James P, Wallace Douglas G, Hamilton Derek A
Department of Psychology, University of New Mexico, Albuquerque, NM 87131, USA.
Psychology Department, Northern Illinois University, DeKalb, IL 60115, USA.
Behav Brain Res. 2015 Aug 1;289:105-17. doi: 10.1016/j.bbr.2015.04.026. Epub 2015 Apr 20.
The hippocampus and dorsolateral striatum are critically involved in spatial navigation based on extra-maze and intra-maze cues, respectively. Previous reports from our laboratory suggest that behavior in the Morris water task may be guided by both cue types, and rats appear to switch from extra-pool to intra-pool cues to guide navigation in a sequential manner within a given trial. In two experiments, rats with hippocampal or dorsolateral striatal lesions were trained and tested in water task paradigms that involved translation and removal of a cued platform within the pool and translations of the pool itself with respect to the extra-pool cue reference frame. In the first experiment, moment-to-moment analyses of swim behavior indicate that hippocampal lesions disrupt initial trajectories based on extra-pool cues at the beginning of the trial, while dorsolateral striatal lesions disrupt subsequent swim trajectories based on the location of the cued platform at the end of the trial. In the second experiment, lesions of the hippocampus, but not the dorsolateral striatum, impaired directional responding in situations where the pool was shifted within the extra-pool cue array. These results are important for understanding the cooperative interactions between the hippocampus and dorsolateral striatum in spatial learning and memory and establish that these brain areas are continuously involved in goal-directed spatial navigation. These results also highlight the importance of the hippocampus in directional responding in addition to place navigation.
海马体和背外侧纹状体分别在基于迷宫外部线索和迷宫内部线索的空间导航中起着关键作用。我们实验室之前的报告表明，莫里斯水迷宫任务中的行为可能受这两种线索类型的引导，并且在给定的试验中，大鼠似乎会依次从池外线索切换到池内线索来引导导航。在两个实验中，对海马体或背外侧纹状体受损的大鼠进行训练，并在水迷宫任务范式中进行测试，这些范式涉及在水池内平移和移除有线索提示的平台，以及相对于池外线索参考框架平移水池本身。在第一个实验中，对游泳行为的即时分析表明，海马体损伤会破坏试验开始时基于池外线索的初始轨迹，而背外侧纹状体损伤会破坏试验结束时基于有线索提示平台位置的后续游泳轨迹。在第二个实验中，海马体损伤而非背外侧纹状体损伤，在水池在池外线索阵列中发生移动的情况下，损害了方向反应。这些结果对于理解海马体和背外侧纹状体在空间学习和记忆中的协同相互作用很重要，并表明这些脑区持续参与目标导向的空间导航。这些结果还突出了海马体在位置导航之外的方向反应中的重要性。
