Aging and the Cognitive and Neural Bases of Implicit Associative Learning

描述（由申请人提供）：总体目标是了解内隐概率联想学习的认知和神经基础，以及这些基础如何随成人年龄而变化。学习被认为是内隐的，当人们获得有关结构性学习的信息时，并不打算学习或意识到他们已经学到了什么。内隐学习对于适应世界可能比外显/陈述性学习更重要，特别是在成年后期，在正规教育中花费的时间很少，这种环境强调外显学习。尽管如此，内隐学习的老化研究得很少，也许是因为与年龄相关的缺陷有时很小或不存在。这种明显的节省产生了一个悖论：联想内隐学习需要神经系统，这些神经系统在健康老龄化过程中表现出结构和功能的下降，那么老年人如何相对擅长它呢？这是通过采用两个研究领域的主题来解决的：认知神经科学提供的证据表明，两个互动学习系统-一个基于内侧颞叶（MTL），另一个基于纹状体-可以有助于这种学习。衰老的认知神经科学提供的证据表明，这些神经系统中的一个对衰老比另一个更敏感，老年人的大脑通常与年轻人的大脑不同地完成相同的任务。这些主题引出了两个假设。首先，内隐概率联想学习在健康老龄化中并没有幸免，而是以早在中年就可以检测到的持续的与年龄相关的学习缺陷为特征。这些赤字是更明显的做法的进展，不能仅仅归因于一般处理资源的年龄相关的赤字。相反，它们反映了纹状体学习系统功能的根本缺陷。第二，这些系统的相对平衡随着年龄的变化而变化;在早期训练中，MTL系统在年轻人和老年人中占主导地位，但随着训练的进行，年轻人开始依赖纹状体系统，而老年人继续依赖相对完整的MTL系统。这使得老年人在训练的早期就能保持接近年轻人的表现水平，而不是以后。这些假设将进行行为和神经影像学研究，使用最近开发的三重学习任务（TLT）进行测试。目的1是表征内隐概率联想学习的年龄差异。目的2是测试行为的影响，老化的互动系统的假设，和目的3是表征的神经基础的隐式概率联想学习的年轻人和老年人，并将它们与行为。这些目标对于促进成功的老龄化和独立生活非常重要，因为内隐联想学习是适应新的人，环境和技术以及在受伤后重新学习技能所必需的。 公共卫生相关性：了解内隐学习形式的认知和神经基础，以及如何在所有年龄段最大限度地提高这种学习，是促进成功衰老的关键，因为内隐学习对于适应新环境和新人群以及在受伤和中风后恢复功能至关重要。此外，确定内隐学习如何受到健康衰老的影响将最终有助于区分健康衰老和病理衰老（例如，阿尔茨海默病）。如果内隐学习在病理性衰老中得以保留，它可以成为补救的基础，从而延长独立生活，改善患者和护理人员的生活质量。

DESCRIPTION (provided by applicant): The overall aim is to understand the cognitive and neural bases of implicit probabilistic associative learning and how these vary with adult age. Learning is said to be implicit when people acquire information about structural regularities without intending to learn or becoming aware of what they have learned. Implicit learning is likely more important for adapting to the world than its explicit/declarative counterparts, particularly in later adulthood when little time is spent in formal schooling, a setting which emphasizes explicit learning. Nonetheless, the aging of implicit learning has been studied much less, perhaps because age-related deficits have sometimes been small or non-existent. This apparent sparing creates a paradox: Associative implicit learning calls on neural systems that show structural and functional declines in healthy aging, and so how would older people be relatively good at it? This is addressed by adopting themes from two research areas: Cognitive neuroscience provides evidence that two interactive learning systems--one based on the Medial Temporal Lobe (MTL) and the other based on the striatum--can contribute to such learning. The cognitive neuroscience of aging provides evidence that one of these neural systems is more sensitive to aging than the other, and that older brains often do the same task differently from younger brains. These themes lead to two hypotheses. First, that implicit probabilistic associative learning is not spared in healthy aging, but rather is characterized by persistent age-related learning deficits that can be detected as early as middle-age. These deficits are more pronounced as practice progresses, and cannot be attributed solely to age-related deficits in general processing resources. Rather, they reflect a fundamental deficit in the function of the striatal learning system. Second, the relative balance of these systems changes with age; early in training the MTL system dominates in both young and old adults, but as training proceeds the young adults come to rely on the striatal system, whereas the old continue to rely on their relatively intact MTL system. This enables old adults to maintain near- young levels of performance very early in training, but not later. These hypotheses will be tested by conducting behavioral and neuroimaging studies, using a recently developed triplets-learning-task (TLT). Aim 1 is to characterize age differences in implicit probabilistic associative learning. Aim 2 is to test behavioral implications for aging of the interactive systems hypothesis, and Aim 3 is to characterize the neural bases of implicit probabilistic associative learning in young and old adults, and relate them to behavior. These aims are important for fostering successful aging and independent living, because implicit associative learning is needed for adapting to new people, environments, and technologies, as well as for relearning skills after injury. PUBLIC HEALTH RELEVANCE: Understanding the cognitive and neural bases of implicit forms of learning, and how to maximize such learning at all ages, is key to fostering successful aging, because implicit learning is essential for adapting to new environments and people, and for recovering function after injury and stroke. Further, identifying how implicit learning is affected by healthy aging will ultimately help to distinguish healthy from pathological aging (e.g., Alzheimer's disease). To the extent that implicit learning is spared in pathological aging, it can be the basis for remediation, thereby extending independent living, and improving the quality of life of patients and caregivers.