Hormones and learning and memory

任何一个经历过青春期、怀孕、更年期或男性更年期的人都可以证明，激素对我们的大脑和身体有着强大的影响。 雌激素，特别是丰富的“年轻”雌激素，雌二醇，可以对大脑和行为产生深远的影响。 关于使用雌激素促进老年妇女认知能力的争议很多，可能是由于文献中相互矛盾的报道。 我们最近发现，雌二醇对学习的影响不同，这取决于任务的类型（实际上是执行任务所需的大脑区域）和雌性啮齿动物服用的雌二醇剂量。高水平的雌二醇会损害工作记忆（从一次试验到另一次试验的记忆，即你把车停在哪里）和参考记忆（随着时间的推移保持稳定的记忆，即停车场在哪里），而低水平的雌二醇通过前额叶皮层和海马体促进工作记忆，尽管剂量不同。 这些发现表明，雌二醇对参与工作记忆的不同脑区（前额叶皮层和海马）的学习有积极的剂量依赖性影响，但可能对参与参考记忆（海马，尾状核）和条件位置偏好（杏仁核）的脑区有不利影响。

As anyone who has gone through puberty, pregnancy, menopause or andropause can attest, hormones exert powerful effects over our brains and body. Estrogen, particularly the abundant "youthful" estrogen, estradiol, can exert profound effects on both brain and behaviour. There is a lot of controversy surrounding the use of estrogens to promote cognition in older women, likely due to conflicting reports in the literature. We have recently found that estradiol affects learning differentially depending on the type of task (and indeed the brain region required to perform the task) and the dose of estradiol administered to female rodents. High levels of estradiol impair both working (memory that changes from trial to trial, i.e. where you park your car) and reference memory (memory that stay stable over time, i.e where the parking lot is), while low levels of estradiol facilitate working memory via the prefrontal cortex and hippocampus albeit at different doses. These findings suggest that estradiol has a positive dose-dependent effect on learning in different brain regions that are involved in working memory (prefrontal cortex and hippocampus) but may have a detrimental effect on brain regions that are involved in reference memory (hippocampus, caudata) and conditioned place preference (amygdala).