Age-related cognitive decline and compensatory brain activity in explicit and imp

描述（由申请人提供）：正常的衰老伴随着脑容量和前额皮质（PFC）连通性的物理下降，以及与工作记忆和执行控制相关的认知能力的变化。与大脑皮层下结构相关的功能，如内隐学习，在非病理性衰老中衰退相对较小。在PFC功能下降的情况下，随着任务需求的增加，老年人对PFC资源的吸收与年轻人不同。尽管许多证据支持这种增加的激活是“补偿性”的观点，但存在不一致和替代说法。Cabeza和Dennis（2012）最近提出了标准，以澄清在何种条件下活动增加应被视为补偿性。该标准区分了成功和不成功的补偿，并应使有关年龄相关的补偿激活的文献有序。然而，这些标准并不能预测什么时候工作条件会导致补偿。我们对补偿有效性的理解将受益于在一个理论框架内的系统检查，该框架预测任务表现何时应该与PFC功能相关联，何时不应该与PFC功能相关联。在分类研究文献中存在这样一个框架。该理论被称为COVIS（言语和内隐系统之间的竞争），它假设外显（可言语的）类别规则学习是由PFC介导的，而内隐（不可言语的）规则学习是由皮层下结构介导的。这一预测，当与上述标准相结合时，提供了一个独特的机会来增加对认知技能的主要细分-显性和隐性推理的补偿性成功和失败的理解。在拟议的实验中，年轻人和老年人将执行由PFC或皮层下区域介导的简单类别学习任务。PFC血流将使用功能性近红外光谱（fNIR）来测量与任务需求相关的激活变化的时间和持续时间。对于明确的规则，补偿性激活应该有助于学习过程中的表现。在学习隐性规则的过程中，PFC应该尝试补偿，但不成功，产生长时间的活动增加——这是Cabeza和Dennis的标准预测的无效补偿的标志。我们计划从几个角度来探索这一基本预测，比较年轻人和老年人、任务难度水平、双重任务需求以及与大脑完整性相关的个体差异预测因素。这种方法对于预测正常的与年龄相关的大脑变化以及不同大脑区域的创伤性损伤的结果具有价值。

DESCRIPTION (provided by applicant): Normal aging is accompanied by physical decline in brain volume and connectivity in the prefrontal cortex (PFC), along with changes in cognitive abilities related to working memory and executive control. Functions tied to sub-cortical brain structures, such as implicit learning, see relatively less decline in non-pathological aging. In response to declining PFC function, older adults appear to recruit PFC resources differently than young adults as task demands increase. Although much evidence supports the notion that this increased activation is "compensatory", inconsistencies and alternative accounts exist. Cabeza & Dennis (2012) recently proposed criteria to clarify conditions under which increased activity should be considered compensatory. The criteria distinguish between successful and unsuccessful compensation and should bring order to the literature on age-related compensatory activation. The criteria, however, do not predict when task conditions should result in compensation. Our understanding of compensatory effectiveness would benefit from systematic examination within a theoretical framework that predicts when task performance should and should not be linked to PFC function. Such a framework exists in the categorization research literature. The theory, called COVIS (for COmpetition between Verbal and Implicit Systems) posits that explicit (verbalizable) category rule learning is mediated by PFC, while implicit (nonverbalizable) rule learning is mediated by subcortical structures. This prediction, when combined with the criteria described above, provides a unique opportunity to increase understanding of compensatory success and failure across a major subdivision of cognitive skill - explicit and implicit reasoning. In the proposed experiments, young and older adults will perform simple category learning tasks that are mediated by either PFC or subcortical regions. PFC blood flow will be measured using functional Near Infrared spectroscopy (fNIR) to measure the timing and duration of changes in activation related to task demands. For explicit rules, compensatory activation should aid performance during learning. During learning of implicit rules, PFC compensation should be attempted but unsuccessful, producing an extended period of increased activity - a hallmark of ineffective compensation predicted by Cabeza & Dennis's criteria. We plan to explore this fundamental prediction from several perspectives, comparing young and older adults, levels of task difficulty, dual task demands, and individual-difference predictors related to brain integrity. This approach holds value for predicting normal age-related brain changes, as well as the results of traumatic injury in different brain regions.