EFFECTS OF AGING ON MEMORY FOR SOURCE OF INFORMATION

与年轻人相比，老年人不仅难以记住内容，尤其是他们在记住信息的来源(例如，说话人、时间或空间背景、通道)方面存在问题。随着人口老龄化，这种自传式或“情节式”记忆的丧失将影响到越来越多的人。能够记住信息，但不能记住其来源，其潜在的实际后果是多方面的--从记住喷雾剂的挫败感，到在目击证人的情况下增加错误记忆的可能性，或者发展成妄想症。本研究侧重于情景记忆的提取和评价阶段(来源监控)。这些过程在自我启动或反思活动的程度上有所不同。启发式过程相对简单，涉及基于现成信息的容易匹配。系统化的过程更复杂(受控)，包括自我启动的检索和更简单过程的迭代。现有证据表明，随着任务的反思性需求变得更大，老年人更有可能出现缺陷。此外，来自大脑受损人群和神经成像研究的证据表明，前额叶皮质(PFC)对于情景记忆非常重要。基于对文献的新分析和我们的初步发现，我们假设右侧PFC的区域服从相对启发式的过程，而左侧PFC或左右PFC之间的双边合作服从更系统的过程。我们还提出，与年龄相关的来源监测下降的生理基础很大程度上是由于招募左PFC的过程的功能障碍，或右和左PFC的相互作用。我们使用自然主义(如目击者记忆、说话人识别)任务来评估多维记忆的监控，并使用更简单的任务来分离来源监控的各个组成部分过程。记忆质量的主观评定与更客观的源记忆行为测量相结合，以评估源监控的离散和连续量化模型的充分性。认知/行为方法与功能磁共振成像技术相结合，以调查来源归因过程的子成分中潜在的与年龄相关的差异及其神经基础，包括使用多个决策维度的能力降低，在维度之间切换的难度增加，以及在一个或多个维度上维持适当标准的困难。

Compared to younger adults, older adults not only have difficulty remembering the content but, especially, they have problems in remembering the source (e.g., speaker, temporal or spatial context, modality) of information. Such a loss of autobiographical or "episodic" memory will affect an increasing number of people as the population ages. The potential practical consequences of being able to remember information, but not its source, are far-ranging-from the frustration of remembering puffing medicine away for safekeeping but not where, to potential increased vulnerability to false memories in eyewitness situations or to the development of delusions. The proposed research focuses on the retrieval and evaluation phase of episodic remembering (source monitoring). These processes vary in degree of self-initiated or reflective activity. Heuristic processes are relatively simple, involving easy matches based on readily available information. Systematic processes are more complex (controlled), involving self-initiated retrieval and iterations of simpler processes. Available evidence suggests that as the reflective demands of tasks become greater, older adults are more likely to show deficits. Furthermore, evidence from brain damaged populations and from neuroimaging studies, suggests that prefrontal cortex (PFC) is important for episodic remembering. Based on a new analysis of the literature and our preliminary findings, we hypothesize that regions in right PFC subserve relatively heuristic processes and that left PFC or bilateral cooperation between right and left PFC subserve more systematic processes. We also propose that the physiological basis for age- related declines in source monitoring is largely due to dysfunction of processes that recruit left PFC, or the interaction of right and left PFC. We use naturalistic (e.g., eyewitness memory, speaker identification) tasks for assessing the monitoring of multidimensional memories and simpler tasks to isolate various component processes of source monitoring. Subjective ratings of qualities of memories are combined with more objective behavioral measures of source memory to assess the adequacy of discrete and continuous quantitative models of source monitoring. A cognitive/behavioral approach is combined with fMRI imaging techniques to investigate potential age-related differences in, and the neural basis of, subcomponents of source attribution processes, including reduced ability to use multiple decision dimensions, greater difficulty switching between dimensions, and difficulty maintaining appropriate criteria on one or more dimensions.