Opitz Bertram
Department of Psychology, University of Surrey, Guildford, UK.
Front Neurol Neurosci. 2014;34:51-9. doi: 10.1159/000356422. Epub 2014 Apr 16.
There has been a long tradition in memory research of adopting the view of a vital role of the medial temporal lobe and especially the hippocampus in declarative memory. Despite the broad support for this notion, there is an ongoing debate about what computations are performed by the different substructures. The present chapter summarizes several accounts of hippocampal functions in terms of the cognitive processes subserved by these structures, the information processed, and the underlying neural operations. Firstly, the value of the distinction between recollection and familiarity for the understanding of the role the hippocampus plays in memory is discussed. Then multiple lines of evidence for the role of the hippocampus in memory are considered. Cumulating evidence suggests that the hippocampus fosters the binding of disparate cortical representations of items and their spatiotemporal context into a coherent representation by means of a sparse conjunctive neural coding. This association of item and context will then lead to the phenomenological experience of recollection. In contrast, surrounding cortical areas have broader neural coding that provide a scalar signal of the similarity between two inputs (e.g. between the encoding and the retrieval). By this they form the basis of a feeling of familiarity, but also might encode the commonalities between these different inputs. However, a more complete picture of the importance of the hippocampus for declarative memories can only be drawn when the interactions of the medial temporal lobe with other brain areas are also taken into account.
在记忆研究领域，长期以来一直存在这样一种观点，即内侧颞叶尤其是海马体在陈述性记忆中起着至关重要的作用。尽管这一观点得到了广泛支持，但关于不同子结构执行何种计算仍存在持续的争论。本章从这些结构所支持的认知过程、所处理的信息以及潜在的神经操作等方面，总结了几种关于海马体功能的观点。首先，讨论了回忆与熟悉感之间的区分对于理解海马体在记忆中所起作用的价值。然后考虑了多条支持海马体在记忆中作用的证据。越来越多的证据表明，海马体通过稀疏的联合神经编码，促进将项目的不同皮层表征与其时空背景绑定成一个连贯的表征。项目与背景的这种关联随后将导致回忆的现象学体验。相比之下，周围的皮层区域具有更广泛的神经编码，可提供两个输入（例如编码与检索之间）相似性的标量信号。由此它们构成了熟悉感的基础，但也可能编码这些不同输入之间的共性。然而，只有在考虑内侧颞叶与其他脑区的相互作用时，才能更全面地了解海马体对陈述性记忆的重要性。
