Malkova Ludise, Mishkin Mortimer
Department of Pharmacology, Georgetown University Medical Center, Washington, DC 20007, USA.
J Neurosci. 2003 Mar 1;23(5):1956-65. doi: 10.1523/JNEUROSCI.23-05-01956.2003.
In earlier studies of one-trial spatial memory in monkeys (Parkinson et al., 1988; Angeli et al., 1993), severe and chronic memory impairment for both object-place association and place alone was found after ablation of the hippocampal formation. The results appeared to provide the first clear-cut evidence in the monkey of the essential role of the hippocampus in spatial memory, but that interpretation neglected the inclusion in the lesion of the underlying posterior parahippocampal region. To determine the separate contributions of the hippocampus and posterior parahippocampal region to these spatial forms of one-trial memory, we trained 10 rhesus monkeys, as before, to remember the spatial positions of either two different trial-unique objects overlying two of the wells in a three-well test tray (object-place trials) or simply two of the three wells (place trials). Six of the monkeys then received ibotenic acid lesions restricted to the hippocampal formation (group H), and the four others received selective ablations of the posterior parahippocampal region (group P), comprising mainly parahippocampal cortex, parasubiculum, and presubiculum. Group H was found to be completely unaffected postoperatively on both types of trials, whereas group P sustained an impairment on both types equal in magnitude to that observed after the combined lesions in the original studies. Thus, contrary to the previous interpretation, one-trial memory for object-place association and, perhaps more fundamentally, one-trial memory for two different places appear to be critically dependent not on the hippocampal formation but rather on the posterior parahippocampal region.
在早期对猴子单次空间记忆的研究中（帕金森等人，1988年；安杰利等人，1993年），发现海马结构被切除后，对于物体-位置关联以及单独位置的严重且慢性记忆损伤。这些结果似乎首次在猴子身上明确证明了海马体在空间记忆中的关键作用，但这种解释忽略了损伤范围包括了潜在的海马旁后区域。为了确定海马体和海马旁后区域对这些单次记忆空间形式的各自贡献，我们像之前一样训练了10只恒河猴，让它们记住三个测试孔板中两个不同的、每次试验都独特的物体覆盖在两个孔上的空间位置（物体-位置试验），或者仅仅记住三个孔中的两个孔的位置（位置试验）。然后，其中6只猴子接受了仅限于海马结构的鹅膏蕈氨酸损伤（H组），另外4只接受了海马旁后区域的选择性切除（P组），主要包括海马旁皮质、副下托和前下托。结果发现，H组在术后两种类型的试验中都完全未受影响，而P组在两种类型的试验中都出现了与原始研究中联合损伤后观察到的程度相同的损伤。因此，与之前的解释相反，对于物体-位置关联的单次记忆，也许更根本的是，对于两个不同位置的单次记忆，似乎关键不依赖于海马结构，而是依赖于海马旁后区域。
