Menopause has been linked to changes in memory. Oestrogen-containing hormone therapy is prescribed to treat menopause-related symptoms and can ameliorate memory changes, although the parameters impacting oestrogen-related memory efficacy are unclear. Cognitive experience and practice have been shown to be neuroprotective and to improve learning and memory during ageing, with the type of task playing a role in subsequent cognitive outcomes. Whether task complexity matters, and whether these outcomes interact with menopause and oestrogen status, remains unknown. To investigate this, we used a rat model of surgical menopause to systematically assess whether maze task complexity, as well as order of task presentation, impacts spatial learning and memory during middle age when rats received vehicle, low-17β-oestradiol (E₂) or high-E₂ treatment. The direction, and even presence, of the effects of prior maze experience differed depending on the E₂ dose. Surgical menopause without E₂ treatment yielded the least benefit, as prior maze experience did not have a substantial effect on subsequent task performance for vehicle treated rats regardless of task demand level during the first exposure to maze experience or final testing. High-dose E₂ yielded a variable benefit, and low-dose E₂ produced the greatest benefit. Specifically, low-dose E₂ broadly enhanced learning and memory in surgically menopausal rats that had prior experience on another task, regardless of the complexity level of this prior experience. These results demonstrate that E₂ dose influences the impact of prior cognitive experience on learning and memory during ageing, and highlights the importance of prior cognitive experience in subsequent learning and memory outcomes.

中文翻译：

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雌激素治疗调节中年手术绝经大鼠认知体验和任务复杂性对记忆的影响


更年期与记忆力的变化有关。含雌激素的激素疗法用于治疗更年期相关症状，并可以改善记忆变化，尽管影响雌激素相关记忆功效的参数尚不清楚。认知经验和实践已被证明具有神经保护作用，并可以改善衰老过程中的学习和记忆，而任务类型在随后的认知结果中发挥着作用。任务复杂性是否重要，以及这些结果是否与更年期和雌激素状态相互作用，仍然未知。为了研究这一点，我们使用手术绝经大鼠模型来系统评估当大鼠接受载体、低 17β-雌二醇 (E ₂ ) 时，迷宫任务的复杂性以及任务呈现的顺序是否会影响中年期间的空间学习和记忆或高E ₂处理。先前迷宫经历的影响的方向甚至存在都因E ₂剂量的不同而不同。没有E ₂治疗的手术绝经产生的益处最小，因为无论第一次接触迷宫经历或最终测试期间的任务需求水平如何，先前的迷宫经历对媒介物处理的大鼠的后续任务表现没有显着影响。高剂量E ₂产生不同的益处，而低剂量E ₂产生最大益处。具体来说，低剂量 E ₂广泛增强了手术绝经大鼠的学习和记忆能力，这些大鼠先前有另一项任务的经验，无论先前经验的复杂程度如何。 这些结果表明，E ₂剂量会影响先前认知经验对衰老过程中学习和记忆的影响，并强调先前认知经验在后续学习和记忆结果中的重要性。