It is already known that oestrogens affect memory and learning, but not exactly how it is done. In an exciting new study, researchers including psychology professor Elena Choleris and biomedical sciences professor Neil MacLusky from the University of Guelph, have shown, that oestrogens affect the brain by boosting short-term learning.
Dr Anna Phan, the lead author on the paper published in the Proceedings of the National Academy of Sciences (PNAS), had previously shown that injections of systemic oestrogen improved the learning of mice. Coupled with the knowledge that oestrogens stimulate a part of the brain involved in cognition and memory, called the hippocampus, this new study looked at the effects of the hormone in this region of the brain. The researchers looked at how learning improved during the first 40 minutes after injecting oestrogen directly into hippocampal regions.
Learning in the mice was assessed by analysing how easily they recognised objects, other mice or objects in novel locations.
Neurons are cells in the brain that pass signals or “messages” to each other through cellular extensions called axons and dendrites. Axons of one neuron interact with dendrites (or spines) of a neighbouring neuron. Minutes after injecting oestrogen into the mice, the researchers noticed a large number of dendritic spines growing where the two neurons meet.
Until now, it has been thought that oestrogens increase the number of these connections and that these would increase the amount of information and learning ability. However, these connections appear to remain “silent” or immature, unless they are used for learning. The more we learn, the stronger these connections get, while those that are not used are “pruned” away by experience.
The research team also expected to see more electrical activity in the neurons with the increased number of spines, but surprisingly found the opposite to be true.
Prof. Choleris described this boost in potential short-term learning as a “use it, or lose it” process, but that more research is required to understand the exact mechanism. She stated that other studies have shown that post-menopausal women or women who have had their ovaries removed, report problems with memory and cognitive ability. This study suggests that boosting oestrogen levels could help with this problem.
However, research has indicated a link between oestrogen replacement therapy and an increased risk of cancer in some woman. That is why Prof. Choleris and her fellow researchers would ideally like to identify the mechanism that oestrogen plays in learning, without increasing the risk of cancer.
If you are a woman who relates to this study, whether it be due to fertility issues, the menopause or if you have had to have your ovaries removed due to a medical condition such as cancer, Euromedic Healthcare can help you in finding the best medical specialist to assist you with your medical condition.