• brain-derived neurotrophic factor;
  • Morris water maze;
  • central nervous system;
  • behavioral flexibility;
  • elevated plus-maze;
  • rat


The present study evaluated the effects of a single intrahippocampal administration of brain-derived neurotrophic factor (BDNF) on memory retention in a water maze. Adult rats were trained in a water maze (acquisition phase, day 1). Immediately after the last training trial subjects were injected in the right hippocampus with either BDNF (24 μg) or phosphate-buffered saline (1 μl). On day 2, all subjects were tested for memory retention in a probe trial and were subsequently tested for reversal learning. While no differences emerged in the probe trial, BDNF-treated subjects showed a shorter latency and a shorter path length to reach the platform during the reversal phase. A significant difference in their “turn angle” and in their swim paths suggests that they might have used a different search strategy compared with controls. Moreover, all subjects also underwent an elevated-plus maze test. BDNF-treated-animals showed a clear tendency to spend a greater amount of time in the open arms and a significantly higher frequency of grooming behavior and of the stretched-attend posture in this maze area, but no differences in locomotion. Overall, these results indicate that administration of BDNF improves performance in a spatial memory task and has enduring effects on emotional behavior. © 2004 Wiley-Liss, Inc.