Retrograde amnesia after hippocampal damage: recent vs. remote memories in two tasks.
We review evidence from experiments conducted in our laboratory on retrograde amnesia in rats with damage to the hippocampal formation. In a new experiment reported here, we show that N-methyl-D-aspartate (NMDA)-induced hippocampal damage produced retrograde amnesia for both hidden platform and two-choice visible platform discriminations in the Morris water task. For both problems there was a significant trend for longer training-surgery intervals to be associated with worse retention performance. Little support is offered by our work for the concept that there is a process involving hippocampal-dependent consolidation of memories in extrahippocampal permanent storage sites. Long-term memory consolidation may take place within the hippocampus. The hippocampus may be involved permanently in storage and/or retrieval of a variety of relational and nonrelational memories if it was intact at the time of learning, even involving information which is definitely not affected in anterograde amnesia after hippocampal damage.
Sutherland
R J
RJ
Department of Psychology, University of New Mexico, Albuquerque 87131-1161, USA. Sutherla@unm.edu
Weisend
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Mumby
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Astur
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Hanlon
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Koerner
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Thomas
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Wu
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Moses
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Cole
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Hamilton
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Hoesing
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D000648:Amnesia, Retrograde / Q000473:pathology* / Q000503:physiopathology*; D000818:Animals; D004193:Discrimination Learning / Q000502:physiology*; D006624:Hippocampus / Q000473:pathology*; D008568:Memory / Q000502:physiology*; D051381:Rats; D013028:Space Perception / Q000502:physiology