Hippocampal system and declarative (relational) memory: Summarizing the data from functional neuroimaging studies

In the last several years there have been impressive strides in the ability to explore the nature of hippocampal system functioning in humans by emplo ying functional neuroimaging methods, permitting such methods to be used in conjunction with neuropsychological methods to better understand the role of the hippocampal system in memory In this paper, we review the literature on functional imaging studies of the hippocampal system, summarizing the d ata and testing these data against a number of theories or explanatory acco unts of hippocampal function. We consider five alternative explanatory acco unts of, or ideas about, hippocampal function- some from already existing w ork, for which the functional imaging data can provide a new test, and othe rs that have emerged directly from the functional imaging work, and that ha ve yet to be tested for their fit of data from neuropsychological methods. We conclude that the relational (declarative) memory account, in which it i s proposed that the hippocampal system plays a critical role in binding tog ether multiple inputs to permit representations of the relations among the constituent elements of scenes or events, can better accomodate the full ra nge of imaging (and other existing) data than any other explanatory account of hippocampal function. Hippocampus 1999;9:83-98. (C) 1999 Wiley-Liss, In c.