Physiol. Res. 55: 445-452, 2006

Evidence for Hippocampal Role in Place Avoidance Other Than Merely Memory Storage


1Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic, 2Institute of Neuroscience, University of Oregon, Eugene and 3State University of New York, Downstate Medical Center, Brooklyn, NY, USA

Received June 26, 2005
Accepted August 5, 2005
On-line available October 17, 2005

Spatial navigation is used as a popular animal model of higher cognitive functions in people. The data suggest that the hippocampus is important for both storing spatial memories and for performing spatial computations necessary for navigation. Animals use multiple behavioral strategies to solve spatial tasks often using multiple memory systems. We investigated how inactivation of the rat hippocampus affects performance in a place avoidance task to determine if the role of the hippocampus in this task could be attributed to memory storage/retrieval or to the computations needed for navigation. Injecting tetrodotoxin (TTX) into both hippocampi impaired conditioned place avoidance, but after injecting only one hippocampus, the rats learned the place avoidance as well as without any injections. Retention of the place avoidance learned with one hippocampus was not impaired when the injection was switched to the hippocampus that had not been injected during learning. The result suggests that during learning, the hippocampus did not store the place avoidance memory.

Key words
Navigation • Multiple memories • Temporary inactivation • Tetrodotoxin • Rat

© 2006 by the Institute of Physiology, Czech Academy of Sciences