Departments of Radiation Sciences and Integrative Medical Biology, Umeå University and Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden.
J Intern Med. 2017 Jan;281(1):65-74. doi: 10.1111/joim.12533. Epub 2016 Jul 25.
The episodic long-term memory system supports remembering of events. It is considered to be the most age-sensitive system, with an average onset of decline around 60 years of age. However, there is marked interindividual variability, such that some individuals show faster than average change and others show no or very little change. This variability may be related to the risk of developing dementia, with elevated risk for individuals with accelerated episodic memory decline. Brain imaging with functional magnetic resonance imaging (MRI) of blood oxygen level-dependent (BOLD) signalling or positron emission tomography (PET) has been used to reveal the brain bases of declining episodic memory in ageing. Several studies have demonstrated a link between age-related episodic memory decline and the hippocampus during active mnemonic processing, which is further supported by studies of hippocampal functional connectivity in the resting state. The hippocampus interacts with anterior and posterior neocortical regions to support episodic memory, and alterations in hippocampus-neocortex connectivity have been shown to contribute to impaired episodic memory. Multimodal MRI studies and more recently hybrid MRI/PET studies allow consideration of various factors that can influence the association between the hippocampal BOLD signal and memory performance. These include neurovascular factors, grey and white matter structural alterations, dopaminergic neurotransmission, amyloid-Β and glucose metabolism. Knowledge about the brain bases of episodic memory decline can guide interventions to strengthen memory in older adults, particularly in those with an elevated risk of developing dementia, with promising results for combinations of cognitive and physical stimulation.
情景记忆系统支持对事件的记忆。它被认为是最敏感的年龄系统，平均衰退年龄在 60 岁左右。然而，个体之间存在明显的差异，有些人的变化速度快于平均水平，而有些人则没有或变化很小。这种可变性可能与痴呆的风险有关，具有加速情景记忆衰退的个体风险更高。功能磁共振成像 (MRI) 中的血氧水平依赖 (BOLD) 信号或正电子发射断层扫描 (PET) 脑成像已被用于揭示衰老过程中情景记忆下降的大脑基础。几项研究表明，在主动记忆处理过程中，与年龄相关的情景记忆下降与海马体之间存在关联，而在静息状态下研究海马体功能连接进一步支持了这一点。海马体与额顶叶新皮质区域相互作用以支持情景记忆，并且已经表明海马体-新皮质连接的改变有助于情景记忆受损。多模态 MRI 研究和最近的混合 MRI/PET 研究允许考虑各种因素，这些因素可能会影响海马体 BOLD 信号与记忆表现之间的关联。这些因素包括神经血管因素、灰质和白质结构改变、多巴胺能神经传递、淀粉样蛋白-β 和葡萄糖代谢。关于情景记忆下降的大脑基础的知识可以指导干预措施来增强老年人的记忆力，特别是对于那些痴呆风险较高的老年人，认知和身体刺激的组合具有很好的效果。
