Moser M B, Moser E I
Department of Psychology, Norwegian University of Science and Technology, 7034 Trondheim, Norway.
J Neurosci. 1998 Sep 15;18(18):7535-42. doi: 10.1523/JNEUROSCI.18-18-07535.1998.
To determine whether memory is processed in a localized or distributed manner by the hippocampus, we inactivated small regions of the structure in pretrained rats before a retention test. Ibotenic acid-induced lesions removing 40% of the hippocampal tissue disrupted retrieval of spatial memory in a water maze but failed to affect new learning or retrieval of a task that was acquired postoperatively. Partial inactivation of the hippocampus by local intrahippocampal 5-aminomethyl-3-hydroxyisoxazole muscimol infusion also impaired retrieval but not new learning. This impairment was temporary; infusions had no effect on retrieval of predrug performance when the test was conducted 48 hr after the infusion. Systematic variation of the volume of dorsal and ventral hippocampal lesions showed that successful retrieval required the integrity of the entire dorsal 70% of the hippocampus. Our data suggest that although spatial tasks can be acquired with local ensembles of hippocampal neurons when other parts of the hippocampus are inactivated, spatial memory is normally both encoded and retrieved by a widely distributed hippocampal network.
为了确定海马体是以局部还是分布式方式处理记忆，我们在预训练大鼠的记忆保持测试前，使该结构的小区域失活。鹅膏蕈氨酸诱导的损伤去除了40%的海马组织，破坏了水迷宫中空间记忆的提取，但未影响新的学习或术后习得任务的提取。通过局部海马内注入5-氨基甲基-3-羟基异恶唑（蝇蕈醇）使海马体部分失活也损害了记忆提取，但不影响新的学习。这种损害是暂时的；当在注入后48小时进行测试时，注入对药物前表现的提取没有影响。对背侧和腹侧海马损伤体积的系统变化表明，成功的记忆提取需要整个背侧70%海马体的完整性。我们的数据表明，尽管当海马体的其他部分失活时，空间任务可以由局部海马神经元群习得，但空间记忆通常由广泛分布的海马网络进行编码和提取。
