Ferric ions located in hippocampal subfields of the mouse: effects on behavior

Using stereotaxic techniques mice were chronically implanted with either stainless steel or platinum-iridium wire probes aimed at the dentate gyrus of the hippocampus. Following a recovery period these mice were trained in a single-trial inhibitor avoidance task. Significant performance deficits were found in those animals subsequently shown to have ferric ions (Fe+3) bilaterally located in the dentate gyrus. The presence of Fe+3 in other hippocampal subfields did not result in behavioral deficits. We hypothesize that the Fe+3 are of vascular origin. Two hypotheses are suggested to account for the observed correlation between the presence of Fe+3 bilaterally in the dentate gyrus and the observed behavioral deficit.