Nicotinic Receptor Activation in Perirhinal Cortex and Hippocampus Facilitates Aspects of Object Memory
This study investigated the role of nicotinic acetylcholine receptors (nAChR) in object recognition and spatial recognition memory using the spontaneous object recognition (SOR) and object-location (OL) tasks, respectively. Experiments 1 to 4, did not yield any consistent facilitative effects of systemic nAChR activation with nicotine using 24- and 48-hr delays. Using a 72-hr delay, experiments 5 and 8 revealed that systemic pre-sample nicotine dose-dependently facilitated SOR and OL performance, respectively. Experiments 6-7 and 9-10 investigated the potential involvement of the perirhinal cortex (PRh) and hippocampus (HPC) in these systemic effects, with activation of nAChR in both of these brain regions producing facilitative effects on SOR and OL performance. These results not only demonstrate that nAChR facilitate performance on SOR and OL memory tasks, but suggest these effects are mediated by nAChR action in both PRh and HPC. This study indicates that, even though PRh and HPC are functionally distinct, they can interact to enhance performance on tasks for which they are not entirely necessary.