Psychology Department, University of Milano-Bicocca, Milan, Italy.
Exp Brain Res. 2010 Sep;205(3):307-24. doi: 10.1007/s00221-010-2363-7. Epub 2010 Aug 3.
Graceful aging has been associated with frontal hyperactivations in working- and episodic long-term memory tasks, a compensatory process, according to some, that allows the best normal elders to perform these tasks at a juvenile level, in spite of natural cortical impoverishment. In this study, 24 young and 24 healthy elderly participants were compared. Graceful aging was explored by investigating domains where most healthy elders perform like youngers (e.g. lexical-semantic knowledge) and tasks that are typically more challenging, like episodic long-term recognition memory tasks. With voxel-based morphometry, we also studied to what extent changes of fMRI activation were consistent with the pattern of brain atrophy. We found that hyperactivations and hypoactivations of the elders were not restricted to the frontal lobes, rather they presented with task-dependent patterns. Only hypoactivations and normal levels of activation systematically overlapped with regional atrophy. We conclude that compensatory processes associated with graceful aging may not necessarily be a sign of early saturation of executive resources, if this was to be represented by a systematic frontal hyperactivation, but rather they may represent the ability of recruiting new cognitive strategies. We discuss two possible approaches to further test this hypothesis.
优雅衰老与工作记忆和情景长时记忆任务中的额部过度激活有关，根据一些人的说法，这是一种补偿过程，它使表现最好的正常老年人能够以青少年的水平完成这些任务，尽管皮质自然减少。在这项研究中，比较了 24 名年轻参与者和 24 名健康老年人。通过研究大多数健康老年人表现得像年轻人一样的领域（例如词汇语义知识）和通常更具挑战性的任务（例如情景长时识别记忆任务），来探索优雅衰老。我们还使用基于体素的形态测量学来研究 fMRI 激活变化与大脑萎缩模式的一致性程度。我们发现，老年人的过度激活和低激活不仅限于额叶，而是呈现出与任务相关的模式。只有低激活和正常水平的激活与区域萎缩系统地重叠。我们的结论是，如果将其表示为系统的额部过度激活，与优雅衰老相关的补偿过程不一定是执行资源早期饱和的迹象，而可能代表了招募新认知策略的能力。我们讨论了两种可能的方法来进一步检验这一假设。
