Implicit Relational Memory in Aging

描述（由申请人提供）：认知衰老的一个公认的发现是，老年人在情景记忆测试中的表现不如年轻人。情景记忆是情境特定的，比如发生在特定地点和时间的事件。事实上，人们发现上下文细节的记忆缺陷几乎是内容项的两倍。这种记忆缺陷背后的确切机制尚不清楚。老年人表现相对较差的一种解释是，他们在创建和检索链接或关系的过程中受到了损害，这些链接或关系是在即将被记住的事件的不同上下文特征之间形成的。另一种观点认为，情景记忆中明显的损伤是与年龄有关的战略性、控制性过程衰退的一部分。这些过程包括对特征或上下文属性的有意操纵、组织或评估，特别是有意识地检索上下文或关系信息。根据这一观点，在衰老过程中，自动或无意的过程相对未受损害。区分这些不同观点的一种方法是检查内隐关系记忆。内隐记忆指的是无意识的、无意的记忆影响——当以前经历的某些方面影响或促进了新的、看似不相关的情况下的行为。如果编码结合机制的缺陷可以解释后来的情景记忆障碍，那么这种缺陷应该在内隐和外显检索的测试中都很明显。另外，如果老年人在关系信息的战略性、控制性处理方面受损，那么内隐测试不应该出现与年龄相关的缺陷。本项目提出三项研究，旨在确定：1)使用两种互补的范式，关系处理中年龄相关损伤的典型发现是否可以推广到内隐记忆；2)使用功能磁共振成像（fMRI），老年人和年轻人在编码和内隐关系检索过程中是否表现出相似的内侧颞叶（MTL）激活。关键的是，提出的实验旨在解决两个相互竞争的观点；因此，任何方向的结果都旨在为更大的理论背景提供信息。该项目的重点与开展与衰老认知神经科学相关的临床应用研究的更广泛目标保持一致。了解这种关系处理缺陷的本质不仅具有理论意义，而且对老年人的日常记忆功能也具有重要意义。将各种元素结合在一起，形成丰富的上下文表示的能力，是对日常事件成功和连贯记忆的基础。

DESCRIPTION (provided by applicant): A well-established finding in cognitive aging is that older adults do not perform as well as young adults on tests of episodic memory. Episodic memories are contextually-specific, such as events that occurred at a particular place and time. Indeed, memory deficits have been found to be nearly twice as large for contextual details than for content items. The exact mechanism underlying this memory deficit remains unclear. One explanation for older adults' relatively poor performance is an impairment in the process of both creating and retrieving links, or relationships, among the separate contextual features of a to-be remembered episode. An alternative viewpoint posits that the impairment evident in episodic memory is part of a more general age-related decline in strategic, controlled processes. Such processes include the intentional manipulation, organization, or evaluation of features or contextual attributes and, especially, the conscious retrieval of contextual or relational information. According to this view, automatic or unintentional processes remain relatively unimpaired in aging. A way to differentiate between these alternative viewpoints is to examine implicit relational memory. Implicit memory refers to non-conscious, unintentional influences of memory - when some aspect of a previous experience influences or facilitates behavior in a new, seemingly unrelated situation. If a deficit in binding mechanisms at encoding can explain later episodic memory impairment, then such a deficit should be evident using both tests of both implicit and explicit retrieval. Alternatively, if older adults are impaired in strategic, controlled processing of relational information, then an age-related deficit should not occur with implicit testing. The current project proposes three studies aimed at determining: 1) whether the typical finding of age-related impairment in relational processing can be generalized to implicit memory, using two complementary paradigms, and 2) whether older and younger adults exhibit similar medial temporal lobe (MTL) activations during encoding and implicit relational retrieval, using functional magnetic resonance imaging (fMRI). Critically, the proposed experiments are aimed at resolving two competing viewpoints; thus, results in either direction are intended to be informative for the greater theoretical context. The focus of this project is aligned with the broader goal of conducting clinically applicable research related to the cognitive neuroscience of aging. Understanding the nature of this deficit in relational processing is not only of theoretical importance, but also has critical implications for older adults' day-to-day memory function. The ability to bind elements together into a rich, contextual representation is what allows for successful and coherent memories of everyday events.