Que PASA? The posterior-anterior shift in aging
Que PASA? The posterior-anterior shift in aging
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DOI：
10.1093/cercor/bhm155
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发表时间：
2008-05-01
期刊：
影响因子：
3.7
通讯作者：
Cabeza, Roberto
中科院分区：
文献类型：
--
作者：
Davis, Simon W.;Dennis, Nancy A.;Cabeza, Roberto
认知老化的功能性神经影像学研究的一个一致发现是，枕叶活动与年龄相关地减少，同时额叶活动增加。这种老化过程中的前后转移（PASA）通常被归因于功能补偿。本项功能性磁共振成像研究试图：1）确认PASA反映的是老化的影响，而非任务难度的差异；2）检验补偿假说；3）研究PASA是否也适用于去激活情况。年轻和年长的参与者在情景检索和视觉感知任务期间接受扫描，并且确定了两个任务共有的与年龄相关的大脑活动变化。该研究得出了3个主要发现。首先，与难度解释不一致的是，当各组表现相匹配时，在不同任务和置信水平上都发现了PASA模式。其次，支持补偿假说的是，额叶活动与年龄相关的增加与表现呈正相关，与枕叶与年龄相关的减少呈负相关。还发现了顶叶活动与年龄相关的增加以及相关性。最后，支持PASA模式对去激活情况的普遍性，老化减少了后中线皮质的去激活，但增加了内侧额叶皮质的去激活。综上所述，这些发现证明了PASA的有效性、功能和普遍性，以及它对老化的认知神经科学的重要性。
A consistent finding from functional neuroimaging studies of cognitive aging is an age-related reduction in occipital activity coupled with increased frontal activity. This posterior-anterior shift in aging (PASA) has been typically attributed to functional compensation. The present functional magnetic resonance imaging sought to 1) confirm that PASA reflects the effects of aging rather than differences in task difficulty; 2) test the compensation hypothesis; and 3) investigate whether PASA generalizes to deactivations. Young and older participants were scanned during episodic retrieval and visual perceptual tasks, and age-related changes in brain activity common to both tasks were identified. The study yielded 3 main findings. First, inconsistent with a difficulty account, the PASA pattern was found across task and confidence levels when matching performance among groups. Second, supporting the compensatory hypothesis, age-related increases in frontal activity were positively correlated with performance and negatively correlated with the age-related occipital decreases. Age-related increases and correlations with parietal activity were also found. Finally, supporting the generalizability of the PASA pattern to deactivations, aging reduced deactivations in posterior midline cortex but increased deactivations in medial frontal cortex. Taken together, these findings demonstrate the validity, function, and generalizability of PASA, as well as its importance for the cognitive neuroscience of aging.