Rudy J W, Sutherland R J
Department of Psychology, University of Colorado, Boulder 80309, USA.
Hippocampus. 1995;5(5):375-89. doi: 10.1002/hipo.450050502.
Sutherland and Rudy ([1989] Psychobiology 17:129-144) proposed that the hippocampal system is critical to normal learning and memory because of its function as the central part of a configural association system. This system constructs a unique representation of the joint occurrence of the independent elements of a compound. There is evidence consistent with the theory's predictions, however, there also are data that unambiguously demonstrate that, under some conditions, animals lacking an intact hippocampal system acquire configural associations. Thus, Sutherland and Rudy's fundamental assumption cannot be correct. To integrate the supporting and contradictory data, we propose two simple modifications of our position: 1) The critical neural system for configural associations is in cortical circuitry outside the hippocampus, and 2) the output from the hippocampal formation contributes to configural processing by selectively enhancing, thereby making more salient, cortical units representing stimulus conjunctions. This enhancement has two important effects: 1) It decreases the similarity between the configural units representing the co-occurrence of cues and the units representing the cues, and 2) It increases the rate at which the configural units can acquire associative strength. The modified theory explains why damage to the hippocampal formation only impairs learning on a subset of nonlinear discrimination problems. It also integrates recent data on the effects of hippocampal formation damage on conditioning involving context cues and makes novel predictions about performance on nonlinear discrimination problems and place learning.
萨瑟兰和鲁迪（[1989年]《心理生物学》17卷：129 - 144页）提出，海马体系统对正常学习和记忆至关重要，因为它作为一个构型关联系统的核心部分发挥作用。该系统构建了一个关于复合刺激中独立元素共同出现的独特表征。有证据与该理论的预测相符，然而，也有数据明确表明，在某些条件下，缺乏完整海马体系统的动物能够习得构型关联。因此，萨瑟兰和鲁迪的基本假设不可能是正确的。为了整合支持性和矛盾性数据，我们对我们的观点提出两个简单的修正：1）用于构型关联的关键神经系统位于海马体之外的皮质回路中，2）海马结构的输出通过选择性增强从而使代表刺激联结的皮质单元更加突出，对构型加工做出贡献。这种增强有两个重要作用：1）它降低了代表线索共同出现的构型单元与代表线索的单元之间的相似性，2）它提高了构型单元获得联想强度的速率。修正后的理论解释了为什么海马结构受损仅会损害一部分非线性辨别问题的学习。它还整合了关于海马结构损伤对涉及情境线索的条件作用影响的最新数据，并对非线性辨别问题和位置学习的表现做出了新的预测。
