As stated in the introduction, our working hypothesis is that the mechanism by which our EE intervention improves wound healing involves the central nervous system, and its downstream effects on the peripheral healing. While the evidence from this study does not allow us to draw conclusions about the mechanism by which our EE intervention improved wound healing, we did obtain evidence to indicate that this EE intervention impacts the central nervous system. First, hippocampal expression of immediate early genes, a measure of brain neural activity,GW786034 increased in isolation reared rats given Nestlets compared to isolation rearing without Nestlets. This provides evidence that the hippocampus is a brain region that the Nestlets either directly or indirectly target. Second, isolation reared rats with Nestlets evidenced reduced hyperactivity in the open field test, a behavior that is likely mediated, in part, through the hippocampus as open field hyperactivity is thought to result from deficient habituation to a novel environment and habituation to novelty likely involves the hippocampus. Finally,Ibrutinib we found that delivering the pro-bonding hormone oxytocin improved wound healing among isolation reared rats at the same rate as the isolation reared rats provided with Nestlets. This hormone has numerous effects on the brain, including quantitative changes in hippocampal GRs and MRs, enhancement of social bonding, and altered central adrenergic receptor density. The finding that the hippocampus rather than the mPFC showed the most robust IEG expression changes with Nestlet treatment is consistent with the finding that nest building appears to reflect brain hippocampus function. Of interest, the gene with the greatest brain expression change in our prior studies by isolation rearing was not affected by Nestlet treatment. Burrowing, a behavior related to nest building was impaired in rats with a potassium channel defect, a different excitatory mechanism for cells. We can speculate that nest building effects might be mediated through an alternate pathway such as the potassium channel, rather than a glutamate channel. At present, our findings only indicate a causal link between our EE treatment, as well as oxytocin, and improved wound healing in isolation reared rats.