Varieties of human spatial memory: a meta-analysis on the effects of hippocampal lesions

The current meta-analysis included 27 studies on spatial-memory dysfunction in patients with hippocampal damage. Each study was classified on the basi s of the task that was used, i.e., maze learning, working memory, object-lo cation memory, or positional memory. The overall results demonstrated impai rments on all spatial-memory tasks. Clear differences in effect size were f ound between positional memory on the one hand and maze learning, object-lo cation memory, and working memory on the other hand. Lateralization was fou nd only on maze learning and object-location memory. These findings clearly indicate that specific aspects of spatial memory can be affected in variou s degrees in patients with hippocampal lesions. Moreover, these results str ongly support the notion that the hippocampus is important in the processin g of metric positional information, probably in the form of an allocentric cognitive map. (C) 2001 Elsevier Science B.V. All rights reserved.