Neuroscience
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Previous studies have indicated that sex hormones such as prolactin, estradiol and testosterone may play a role in the modulation of adult hippocampal neurogenesis (AHN) in rodents and non-human primates, but so far there has been no investigation of their impact on human hippocampal neurogenesis. Here, we quantify the expression levels of the relevant receptors in human post-mortem hippocampal tissue and a human hippocampal progenitor cell (HPC) line. Secondly, we investigate how these hormones modulate hippocampal neurogenesis using a human in vitro cellular model. ⋯ At this timepoint we instead observe a decrease in proliferation. Overall, our study demonstrates relatively minor, and possibly short-term effects of sex hormones on hippocampal neurogenesis in human cells. Further work will be needed to understand if our results differ to previous animal research due to species-specific differences, or whether it relates to limitations of our in vitro model.
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Cognitive deficits and alterations in emotional behaviour are typical features of Alzheimer's disease (AD). Moreover, exposure to stress or adversity during the early life period has been associated with an acceleration of cognitive deficits and increased AD pathology in transgenic AD mouse models. Whether and how early life adversity affects fear memory in AD mice remains elusive. ⋯ We conclude that in APPswe/PS1dE9 mice, ELS increases fear memory in the conditioning context as well as a novel context, which is accompanied by aberrant hippocampal synaptic potentiation. These results may help to understand how individual differences in the vulnerability to develop AD arise and emphasise the importance of the early postnatal time window in these differences. This article is part of Special Issue entitled: Lifestyle and Brain Metaplasticity.