The effects of environmental complexity on the hippocampal formation of the adult rat

Abstract

In an effort to determine the plasticity of the proliferative matrix of the hippocampus in an adult rat to environmental manipulation, the following study was conducted. Fifteen adult male Long-Evans rats (6 months old at the start of the experiment) were placed into two different environments for 3 months. Seven animals represented the enriched condition and 8 represented the condition of isolation. At the conclusion of exposure to the different environments, the animals were sacrificed by transcardial perfusion and the dorsal hippocampi examined in matched sections for all animals. Results indicated heavier total brain weights and larger numbers of granule cells in the dorsal hippocampus for animals exposed to the enriched environment. Implications for CNS plasticity were discussed.