Abstract: Mnemonic discrimination (MD) refers to the ability to accurately distinguish similar memory experiences, which relies on a neural computing mechanism known as pattern separation. Currently, mnemonic similarity task (MST) is commonly employed to measure and study MD. The elderly tend to exhibit a noticeable decline in MD. This decline is proved to be associated with damage to the structural and functional integrity of the medial temporal lobe, which occurs during the aging process. Some researchers have also suggested that the aging of the neocortex can influence MD. Given its reliance on the medial temporal lobe, MD can reflect abnormal brain structural damage and functional decline in the early stages of cognitive impairment. Thus, MST has significant potential in early identification of cognitive impairment. To further explore the causes of the decline in MD, future studies should employ more advanced imaging techniques to separately investigate the impact of aging in the dentate gyrus and CA3 subregions on MD. It is also critical to research more about the cognitive neural mechanisms underlying the impact of neocortical dysfunction on MD, with a particular focus on age-related changes in cortical-hippocampal interaction mechanisms. Large-scale prospective cohorts should also be established to validate the effectiveness of MST in early identification of cognitive impairment.

记忆辨别力是对相似的记忆经验进行准确辨别的能力,其依赖于名为模式分离的神经计算机制,在人类被试中,通常使用记忆相似性任务对其进行测量与研究。在老化过程中,老年人的记忆辨别力会出现十分明显的衰退,这种衰退与海马、内嗅皮层等内侧颞叶脑区的结构和功能衰退以及其他新皮层结构和功能老化关系密切。由于记忆辨别力高度依赖于内侧颞叶的结构和功能完整性,因此,它能够反映出认知障碍发展早期的异常脑结构和功能变化,使得记忆相似性任务具备了应用于认知障碍早期识别的巨大潜力。未来研究需要采用更精细的成像技术单独考察海马齿状回和CA3亚区在记忆辨别中的作用及其老化的影响,并更多关注前额叶等新皮层结构老化影响记忆辨别力的神经机制,同时也需要建立大样本前瞻队列来验证记忆相似性任务在认知障碍早期识别中的有效性。

国家重点研发计划(2020YFC2003000,2018YFC2001700,2018YFC2000300);; 国家自然科学基金(32271121,32071079)