Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA.
Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA.
Cereb Cortex. 2021 Jan 5;31(2):717-730. doi: 10.1093/cercor/bhaa192.
During demanding cognitive tasks, older adults (OAs) frequently show greater prefrontal cortex (PFC) activity than younger adults (YAs). This age-related increase in PFC activity is often associated with enhanced cognitive performance, suggesting functional compensation. However, the brain is a complex network of interconnected regions, and it is unclear how network connectivity of PFC regions differs for OAs versus YAs. To investigate this, we examined the age-related difference on the functional brain networks mediating episodic memory retrieval. YAs and OAs participants encoded and recalled visual scenes, and age-related differences in network topology during memory retrieval were investigated as a function of memory performance. We measured both changes in functional integration and reconfiguration in connectivity patterns. The study yielded three main findings. First, PFC regions were more functionally integrated with the rest of the brain network in OAs. Critically, this age-related increase in PFC integration was associated with better retrieval performance. Second, PFC regions showed stronger performance-related reconfiguration of connectivity patterns in OAs. Finally, the PFC reconfiguration increases in OAs tracked reconfiguration reductions in the medial temporal lobe (MTL)-a core episodic memory region, suggesting that PFC connectivity in OAs may be compensating for MTL deficits.
在要求较高的认知任务中，老年人（OAs）的前额叶皮层（PFC）活动通常比年轻人（YAs）更为活跃。这种与年龄相关的 PFC 活动增加通常与认知表现的提高有关，表明存在功能代偿。然而，大脑是一个相互关联的区域网络，目前尚不清楚 PFC 区域的网络连接在老年人和年轻人之间有何不同。为了研究这一点，我们考察了在情节记忆检索中调节的功能性大脑网络的年龄相关性差异。YAs 和 OAs 参与者对视觉场景进行了编码和回忆，并研究了记忆检索过程中网络拓扑结构的年龄相关性差异，作为记忆表现的函数。我们测量了功能整合和连接模式重新配置的变化。该研究得出了三个主要发现。首先，OAs 中的 PFC 区域与大脑网络的其他部分具有更高的功能整合性。至关重要的是，这种与年龄相关的 PFC 整合增加与更好的检索表现有关。其次，OAs 中的 PFC 区域表现出更强的与性能相关的连接模式重新配置。最后，OAs 中 PFC 的重新配置增加与内侧颞叶（MTL）的重新配置减少有关，MTL 是一个核心的情节记忆区域，这表明 OAs 中的 PFC 连接可能补偿了 MTL 的缺陷。
