Implicit Relational Memory in Aging

描述(由申请人提供)：认知老化方面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。情节记忆是特定于背景的，比如发生在特定地点和时间的事件。事实上，人们已经发现，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，在创建和提取要记住的情节的单独上下文特征之间的链接或关系的过程中存在障碍。另一种观点认为，情节记忆中明显的损害是更普遍的与年龄相关的战略性受控过程下降的一部分。这些过程包括有意操纵、组织或评估特征或语境属性，尤其是有意识地检索语境或关系信息。根据这一观点，在衰老过程中，自动或无意的过程相对来说没有受到损害。区分这些不同观点的一种方法是考察内隐关系记忆。内隐记忆指的是记忆的无意识、无意的影响--当先前经历的某些方面影响或促进了新的、看似无关的情况下的行为。如果编码时绑定机制的缺陷可以解释后来的情景记忆损害，那么无论是内隐提取还是外显提取，这种缺陷都应该是明显的。或者，如果老年人在战略性的、受控的关系信息处理方面受到损害，那么内隐测试不应该出现与年龄相关的缺陷。目前的项目提出了三项研究，旨在确定：1)关系加工中年龄相关损害的典型发现是否可以推广到内隐记忆，使用两种互补的范式；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提取过程中是否表现出相似的内侧颞叶(MTL)激活。关键的是，拟议的实验旨在解决两个相互竞争的观点；因此，两个方向的结果都旨在为更大的理论背景提供参考。该项目的重点是与更广泛的目标保持一致，即进行与衰老的认知神经科学相关的临床适用研究。了解这种关系处理缺陷的本质不仅具有理论上的重要性，而且对老年人的日常记忆功能也具有重要意义。将元素结合在一起形成丰富的上下文表示的能力允许对日常事件进行成功和连贯的记忆。

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.