Gold April E, Kesner Raymond P
Psychology Department, University of Utah, Salt Lake City, Utah 84112-0251, USA.
Hippocampus. 2005;15(6):808-14. doi: 10.1002/hipo.20103.
Rats were trained on a delayed matching-to-sample for a spatial location task to examine spatial pattern completion. On the sample phase of the task, rats were trained to move a small black block covering a food well that could appear in one of five possible spatial locations. During the choice phase of the task, rats were required to find the same food well, with the block removed so as to receive reinforcement. After reaching stable performance in terms of accuracy to find the correct location, rats received neurotoxic injections into the CA3 subregion of the hippocampus. The control group received vehicle injections into the CA3 subregion. After surgery, four extramaze cues were always available during the sample phase, but during the choice phase zero, one, two, three, or four cues were removed. The results indicate that normal vehicle control injected rats display excellent pattern completion across all reductions in the availability of cues, whereas rats with CA3 lesions are impaired in pattern completion as indicated by a linear increase in errors as the number of available cues is reduced. It appears that the CA3 subregion of the hippocampus plays an important role in spatial pattern completion.
大鼠接受了一项用于空间位置任务的延迟匹配样本训练，以检验空间模式完成能力。在任务的样本阶段，训练大鼠移动一个覆盖食物槽的小黑块，食物槽可能出现在五个可能的空间位置之一。在任务的选择阶段，要求大鼠找到同一个食物槽，此时黑块已被移除，以便获得强化。在找到正确位置的准确性方面达到稳定表现后，给大鼠海马体CA3亚区注射神经毒素。对照组则在CA3亚区注射赋形剂。手术后，在样本阶段始终有四个迷宫外部线索可用，但在选择阶段，会移除零个、一个、两个、三个或四个线索。结果表明，正常注射赋形剂的对照大鼠在所有线索可用性降低的情况下都表现出出色的模式完成能力，而CA3损伤的大鼠在模式完成方面受损，这表现为随着可用线索数量的减少，错误呈线性增加。看来海马体的CA3亚区在空间模式完成中起着重要作用。
