Effects of Age and Resource Depletion on Post-retrieval Monitoring and Individual Differences in Memory Performance

情节记忆随着年龄的增长而显著下降，而且与其他形式的记忆相比，下降得不成比例。 了解健康受试者与年龄相关的间歇性衰退的认知和神经基础很重要 因为即使是健康的人步入70多岁时的轻微损害(以临床标准衡量)，S也是 足以对生活质量产生不利影响。识别特定的认知过程，及其 神经基质是年龄相关性记忆衰退的最主要原因，是年龄相关性记忆衰退的关键先兆 制定潜在的康复干预措施。同样重要的是，充分了解更多 阿尔茨海默氏症等与年龄相关的神经退行性疾病的严重记忆障碍 如果不知道记忆及其神经底物在不同时期是如何变化的，疾病将很难实现 健康寿命的进程。本研究计划的目的是调查在 提取后监控过程中情景记忆成绩的年龄相关差异 支持就事件检索尝试的产品与当前事件的相关性进行评估 行为目标。该计划以两个实验的高度一致的结果为起点 作为正在进行的研究计划的一部分进行的。在这两个实验中，功能磁共振成像在测试项目之间进行对比 对检索后监测提出了高要求和低要求，确定了各区域的不同活动 前额叶皮质此前与监控和其他认知控制过程有关。规模的大小 这些假定的“功能磁共振监测效应”在20多岁的年轻人和老年人之间没有区别。 60年代中期至70年代中期，并与情节记忆表现显著相关。这些发现很耐人寻味 鉴于人们普遍认为PFC支持的认知功能特别容易受到 年龄越来越大。有人建议，这些发现可以从老年人需要 比年轻人更多的神经资源来实现同等水平的表现，因此年龄更大 与年轻人相比，成年人在认知需求水平较低时会遭受资源枯竭的痛苦。因此，它是 预测提取后监测的神经相关因素中的表面年龄不变性及其 与内存性能的关系将在以下情况下破裂： 尤其是当可用于支持监测的认知资源耗尽时。二 提出了一个涉及功能磁共振成像的实验，以及一个涉及TMS的实验。如果预测成真， 研究结果支持这样一种说法，即随着年龄的增长，提取后监控变得更多 当认知需求很高或神经资源耗尽时，容易受到干扰。这些发现 将表明，支持监测的进程将值得在旨在 改善与年龄相关的记忆力衰退。同样重要的是，预测的失败将强烈表明 尽管这是内存性能的重要决定因素，但监控不太可能是一个重要的 年龄相关性记忆力下降的原因。

Episodic memory declines substantially and, relative to other forms of memory, disproportionately, with age. Understanding the cognitive and neural bases of age-related episodic decline in healthy subjects is important because even the modest impairment (by clinical standards) typical of healthy individuals entering their 70’s is sufficient to have a detrimental impact on quality of life. Identifying the specific cognitive processes, and their neural substrates, which are most responsible for age-related memory decline is a crucial precursor to the development of potential rehabilitative interventions. Equally important, a full understanding of the much more severe memory impairments characteristic of age-related neurodegenerative diseases such as Alzheimer’s Disease will be difficult to achieve without knowledge of how memory and its neural substrates vary over the course of the healthy lifespan. The aim of the present research program is to investigate the possible role in age-related differences in episodic memory performance of the ‘post-retrieval monitoring’ processes that support evaluation of the products of an episodic retrieval attempt with respect to their relevance for current behavioral goals. The program takes as its starting point highly consistent findings from two experiments conducted as part of an ongoing research program. In both experiments fMRI contrasts between test items imposing high versus low demands on post-retrieval monitoring identified differential activity in regions of the prefrontal cortex previously implicated in monitoring and other cognitive control processes. The magnitude of these putative ‘fMRI monitoring effects’ did not differ between young adults in their 20s and older adults in their mid-60s to mid-70s, and correlated significantly with episodic memory performance. The findings are intriguing given the widely held view that cognitive functions supported by the PFC are especially vulnerable to increasing age. It is proposed that the findings can be understood from the assumption that older adults require more neural resources than young adults to achieve equivalent levels of performance, and thus that older adults will suffer resource depletion at lower levels of cognitive demand than the young. It is therefore predicted that the seeming age invariance in the neural correlates of post-retrieval monitoring and their relationship with memory performance will break down when the demands placed upon monitoring are especially high, or when the cognitive resources available to support monitoring are depleted. Two experiments, one involving fMRI, and one involving TMS, are proposed. If the predictions are fulfilled, the findings would support the proposal that, with increasing age, post-retrieval monitoring becomes more vulnerable to disruption when cognitive demands are high or neural resources are depleted. These findings would suggest that the processes supporting monitoring would be worth targeting in interventions aimed at ameliorating age-related memory decline. Equally important, failure of the predictions would strongly suggest that, although an important determinant of memory performance, monitoring is unlikely to be a significant cause of age-related memory decline.