Age-related changes in brain activity across the adult lifespan
Age-related changes in brain activity across the adult lifespan
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DOI：
10.1162/jocn.2006.18.2.227
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发表时间：
2006-02-01
影响因子：
3.2
通讯作者：
Winocur, G
中科院分区：
文献类型：
--
作者：
Grady, CL;Springer, MV;Winocur, G
已经出现了许多理论来解释随着年龄的增长而发生的记忆变化。这些理论中的许多都援引了可能影响记忆以外的多个认知领域的机制。这些机制包括注意力或抑制功能的改变，或特定大脑区域（如额叶）的功能障碍。为了深入了解这些机制，我们使用功能性磁共振成像来检查年轻人，中年人和老年人在编码和识别任务中的大脑活动，以确定年龄与各种任务中大脑活动之间的相关性。研究的目的是了解这些相关性是特定于特定任务还是在不同任务之间普遍存在，并确定年龄差异是否在成年后以线性方式出现。在所有的记忆任务中，在编码和识别方面，随着年龄的增长，在任务执行过程中通常会减少的区域（例如，大脑皮层）的活动呈线性增加。例如，在一个实施例中，内侧额叶和顶叶区域），而与任务相关的激活区域（e.例如，在一个实施例中，背外侧前额叶皮层）随年龄增长而下降。这些结果表明，有一个逐渐的，与年龄相关的能力，暂停非任务相关或“默认模式”的活动和从事区域进行记忆任务。默认模式和任务相关活动之间的平衡的这种改变可以解释增加的脆弱性，从无关的信息分心，从而影响多个认知领域。
A number of theories have emerged to explain the well-studied changes in memory that occur with age. Many of these theories invoke mechanisms that have the potential to affect multiple cognitive domains, in addition to memory. Such mechanisms include alterations in attentional or inhibitory function, or dysfunction of specific brain areas, such as the frontal lobes. To gain insight into these mechanisms, we used functional magnetic resonance imaging to examine brain activity during encoding and recognition tasks in young, middle-aged, and older adults to identify correlations between age and brain activity across the various tasks. The goal was to see whether these correlations were task-specific or common across tasks, and to determine whether age differences emerged in a linear fashion over the adult years. Across all memory tasks, at both encoding and recognition, linear increases of activity with age were found in areas normally decreased during task performance ( e. g., medial frontal and parietal regions), whereas activity in regions with task-related activation ( e. g., dorsolateral prefrontal cortex) decreased with age. These results suggest that there is a gradual, age-related reduction in the ability to suspend non-task-related or "default-mode'' activity and engage areas for carrying out memory tasks. Such an alteration in the balance between default-mode and task-related activity could account for increased vulnerability to distraction from irrelevant information, and thereby affect multiple cognitive domains.