LEARNING AND MEMORY AFTER ADRENALECTOMY-INDUCED HIPPOCAMPAL DENTATE GRANULE CELL DEGENERATION IN THE RAT

Citation
Jn. Armstrong et al., LEARNING AND MEMORY AFTER ADRENALECTOMY-INDUCED HIPPOCAMPAL DENTATE GRANULE CELL DEGENERATION IN THE RAT, Hippocampus, 3(3), 1993, pp. 359-371
Citations number
29
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
10509631
Volume
3
Issue
3
Year of publication
1993
Pages
359 - 371
Database
ISI
SICI code
1050-9631(1993)3:3<359:LAMAAH>2.0.ZU;2-#
Abstract
Adrenalectomy (ADX) of normal adult rats causes selective hippocampal dentate granule cell degeneration that is prevented by corticosterone. The ability to destroy this one hippocampal cell type noninvasively m ade it possible to address the role of the dentate granule cells in le arning and memory. Four months after ADX, 31 of 45 rats failed to show obvious granule cell loss and displayed behavior in the Morris water maze that was similar to 16 sham-operated control rats and 16 ADX rats maintained on corticosterone throughout the study. Conversely, 14 of the 45 ADX rats experienced a loss of granule cells that varied from m inimal to extensive. Although there were no obvious differences betwee n groups in motoric and motivational characteristics or search strateg ies. ADX rats with moderate to extensive granule cell loss acquired pl ace learning slightly slower than controls or ADX rats with minimal or no obvious cell loss. Furthermore, the ADX rats with moderate to exte nsive cell loss were temporarily impaired following alteration of eith er intramaze or extramaze cues compared to controls. In contrast, the rats with granule cell loss remembered an old place and learned a new place as quickly as controls. These results suggest that a normal comp lement of dentate granule cells may not be necessary for the acquisiti on or retention of spatial information in the Morris water maze.