Department of Psychology, Center for Studies in Behavioural Neurobiology, Concordia University, Montreal, Quebec, Canada H4B 1R6.
Hippocampus. 2009 Dec;19(12):1212-21. doi: 10.1002/hipo.20583.
A non-navigational test of incidental spatial learning was used to determine whether hippocampal damage causes temporally-graded retrograde amnesia (TGRA) for allocentric-spatial information. Rats were exposed to two identical objects in a circular open field for 7 min on seven consecutive days. In the 1-3 days after the last day of familiarization, rats received neurotoxic lesions of the hippocampal formation (HPC) or sham lesions. Another two groups received the same lesions 3 weeks after familiarization. The rats were then placed back in the open field with one object displaced, and the time spent in each of the quadrants as well as time spent exploring the objects was recorded. Rats that received HPC lesions 3 weeks but not 1-3 days after familiarization showed evidence of preserved remote spatial memory; however, their remote memory was expressed through different behavior than control rats. Rats with HPC lesions spent more time with the displaced object than with the object that remained in the same place, whereas control rats spent more time in the quadrant where the displaced object used to be. These results suggest that remote spatial memories may be preserved with a sufficiently long familiarization-to-surgery interval before HPC lesions, but that the nature of these memories may differ in quantity and/or quality from those of intact rats.
采用非导航性空间学习测试来确定海马损伤是否会导致以时间梯度方式逆行性遗忘（TGRA）的非位置性空间信息。将大鼠暴露在圆形开阔场中的两个相同物体中，每天连续 7 分钟。在最后一天熟悉后的 1-3 天内，大鼠接受海马结构（HPC）的神经毒性损伤或假损伤。另外两组在熟悉后 3 周接受相同的损伤。然后，将大鼠放回有一个物体移位的开阔场中，并记录它们在每个象限中花费的时间以及探索物体的时间。在熟悉后 3 周而非 1-3 天接受 HPC 损伤的大鼠表现出保留远程空间记忆的迹象；然而，它们的远程记忆表现出与对照大鼠不同的行为。接受 HPC 损伤的大鼠花更多的时间与移位的物体在一起，而不是与留在原处的物体在一起，而对照大鼠则花更多的时间在曾经放置移位物体的象限中。这些结果表明，在海马体损伤前有足够长的熟悉到手术间隔时间，可能会保留远程空间记忆，但这些记忆的性质在数量和/或质量上可能与完整大鼠的记忆不同。
