Shapiro M L, Eichenbaum H
Department of Psychology, McGill University, Montreal, Quebec, Canada.
Hippocampus. 1999;9(4):365-84. doi: 10.1002/(SICI)1098-1063(1999)9:4<365::AID-HIPO4>3.0.CO;2-T.
Hippocampal cells contribute to memory by rapidly encoding information about the perceptual and behavioral structure of experience. This paper describes two complementary experimental approaches that illustrate two important mechanisms that confer these properties to hippocampal cells: (1) Enduring spatial memory and stable place fields each depend upon synaptic plasticity mechanisms that normally rely on the same NMDA-receptor mediated metabolic events as long-term potentiation (LTP). Thus, hippocampal cells "learn" to encode information about the perceptual and behavioral structure of experiences. (2) Hippocampal cells encode the structure of experience and respond in a manner inconsistent with a spatial representation. Place fields are distributed heterogeneously in space, their locations are determined by non-geometric information, the population of active cells can indicate more than one location in space, and hippocampal cells encode discriminative stimuli independent of their spatial location. To the extent that the hippocampus encodes a map, it is more simply described as a memory map than a spatial map. Rather than computing spatial locations, the space it encodes is better described as a life or a problem space that encodes the history of experience into the relational structure of episodes.
海马体细胞通过快速编码有关经验的感知和行为结构的信息来促进记忆。本文描述了两种互补的实验方法，阐明了赋予海马体细胞这些特性的两个重要机制：（1）持久的空间记忆和稳定的位置野均依赖于突触可塑性机制，这些机制通常与长时程增强（LTP）一样依赖相同的NMDA受体介导的代谢事件。因此，海马体细胞“学习”编码有关经验的感知和行为结构的信息。（2）海马体细胞编码经验的结构，并以与空间表征不一致的方式做出反应。位置野在空间中分布不均一，其位置由非几何信息决定，活跃细胞群体可指示空间中的多个位置，并且海马体细胞编码与空间位置无关的辨别性刺激。就海马体编码地图而言，与其将其描述为空间地图，不如更简单地将其描述为记忆地图。它所编码的空间并非计算空间位置，而更好地描述为一个生活或问题空间，该空间将经验的历史编码到事件的关系结构中。
