Retrograde amnesia for spatial information: a dissociation between intra and extramaze cues following hippocampus lesions in rats

Eur J Neurosci. 1998 Oct;10(10):3295-301. doi: 10.1046/j.1460-9568.1998.00388.x.

Abstract

Several recent studies have shown a flat retrograde amnesia for spatial information following lesions to the hippocampus in rats and mice. However, the results of the present investigation demonstrate that in rats that presurgically learned a spatial reference memory task based on extramaze cues, a temporally graded retrograde amnesia is evident following lesions to the hippocampus (1, 16, 32 or 64 days after learning) if two conditions are met. First, that a wide range of retention intervals is used, and second, that independent groups of rats are tested, not a single group that learns different spatial discrimination tasks at different times (expt 1). The results of expt 2 show that the hippocampus does not serve as a consolidating mechanism when the spatial task learned presurgically is based on intramaze cues. Taken together, these results indicate that the hippocampus is critical for the storage and/or retrieval of spatial reference information that was learned up to 1 month before hippocampus damage; however, in the absence of the hippocampus, efficient retention can still occur provided that the spatial knowledge was learned in a simple associative manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amnesia, Retrograde / physiopathology*
  • Animals
  • Cues*
  • Hippocampus / injuries*
  • Hippocampus / physiology
  • Male
  • Maze Learning / physiology*
  • Memory / physiology
  • Rats
  • Rats, Wistar
  • Space Perception / physiology*
  • Time Factors