LAUSR

The hippocampus in neonatal rats is not fully developed after birth, and the effect of odor-aversion learning on memory consolidation in the immature hippocampus is not well understood. Therefore, the aim of the present study was to explore the effects of odor-aversion learning in neonatal rats on memory consolidation and neurodevelopment in the immature hippocampus. The effect of hippocampal-induced learning was measured at two different developmental stages using the Y-maze and c-Fos protein levels. Furthermore, hippocampal cell proliferation and growth-associated protein 43 (GAP-43) expression were evaluated at different developmental stages, namely, postnatal day 7 (PN7) and PN24, after odor-aversion learning. Both PN7 and PN24 rats avoided conditioned odor stimuli after odor-aversion learning. PN7 and PN24 rats in the odor-averse learning groups exhibited high c-Fos protein levels. PN7 rats exhibited high cell proliferation rates and GAP-43 protein levels after odor-aversion learning. These results showed that the immature hippocampus can participated in odor-aversion learning, which may induce cell proliferation and axonal development.