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

随着年龄的增长，情节记忆会大幅下降，而且与其他形式的记忆相比，不成比例。 了解健康受试者中年龄相关性发作性衰退的认知和神经基础是重要的 因为即使是进入70多岁的健康人典型的适度损伤（按临床标准）， 足以对生活质量产生不利影响。识别特定的认知过程， 神经基质，这是最负责与年龄相关的记忆衰退是一个重要的前体， 开发潜在的康复干预措施。同样重要的是，充分理解 老年性神经退行性疾病（如阿尔茨海默氏症）的严重记忆障碍 如果不了解记忆及其神经基质在不同的时间段内是如何变化的， 健康的生命周期。本研究计划的目的是调查可能的作用 年龄相关的差异，情节记忆表现的“后检索监测”的过程， 支持评估情景检索尝试的产品与当前的相关性 行为目标该计划以两个实验的高度一致的结果为出发点 作为正在进行的研究计划的一部分。在这两个实验中，功能磁共振成像对比了测试项目 对回收后监测确定的区域内不同活动提出高与低的要求， 前额叶皮层先前与监控和其他认知控制过程有关。的大小 这些假定的“功能磁共振成像监测效应”在20多岁的年轻人和20多岁的老年人之间没有差异。 60年代中期至70年代中期，并与情节记忆成绩显著相关。这些发现很有趣 考虑到广泛认为前额叶皮层支持的认知功能特别容易受到 年龄增长。有人提出，可以从老年人需要的假设来理解这些发现。 更多的神经资源比年轻的成年人达到同等水平的表现，因此，老年人 成年人在认知需求水平低于年轻人的情况下将遭受资源枯竭。因此 预测，似乎年龄不变性的神经相关的检索后监测及其 与内存性能的关系将打破时，对监控的要求， 特别高，或者当可用于支持监测的认知资源耗尽时。两 实验，一个涉及功能磁共振成像，一个涉及TMS，提出。如果预言成真， 研究结果将支持这一建议，即随着年龄的增长，检索后监测变得更加重要。 当认知需求很高或神经资源耗尽时，易受干扰。这些发现 我认为支持监测的流程值得在针对以下目标的干预措施中作为目标 改善与年龄相关的记忆衰退。同样重要的是，预测的失败强烈表明， 尽管监控是内存性能的重要决定因素，但它不太可能是一个重要的因素。 与年龄有关的记忆衰退的原因。

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.