Retrograde amnesia and consolidation: Anatomical and lesion considerations

The four papers in this issue of Hippocampus dealing with retrograde amnesi a, together with relevant animal studies in the literature, are reviewed fr om the perspective of the anatomical location of: the lesion and extent of damage to the brain. In order to evaluate the underlying damage in these an d related prospective experimental studies, it is necessary to consider bot h the lesion techniques that were used as well as the care with which the r esulting damage was determined. Both temporally graded and flat, ungraded r etrograde amnesia have been reported, as well a lack of effects, following damage to structures in the medial temporal area. Most research has centere d around damage to the hippocampus, but differences in selectivity of the l esions and behavioral testing procedures preclude any definite conclusions regarding the precise nature of the involvement of this structure. With a g reater appreciation for the importance of the locus and extent of the damag e, together with the kind of information being processed, if should be poss ible to obtain a better understanding of the neural substrates underlying r etrograde amnesia. (C) 2001 Wiley-Liss, Inc.