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

描述（由申请人提供）：正常衰老伴随着大脑体积和前额叶皮层（PFC）连接性的物理下降，沿着与工作记忆和执行控制相关的认知能力的变化。与皮层下大脑结构相关的功能，如内隐学习，在非病理性衰老中下降相对较少。为了应对PFC功能的下降，随着任务需求的增加，老年人招募PFC资源的方式似乎与年轻人不同。虽然有许多证据支持这种激活增加是“补偿性”的观点，但存在不一致和替代解释。Cabeza & Dennis（2012）最近提出了标准，以澄清增加活动应被视为补偿的条件。这些标准区分了成功和不成功的补偿，并应使与年龄相关的补偿激活的文献。然而，这些标准并不能预测任务条件何时会导致补偿。我们对补偿效应的理解将受益于在理论框架内进行的系统检查，该理论框架预测任务绩效何时应该与PFC功能相关，何时不应该与PFC功能相关。这样一个框架存在于分类研究文献中。该理论被称为COVIS（言语和内隐系统之间的竞争），它假定外显（可言语）类别规则学习是由PFC介导的，而内隐（不可言语）规则学习是由皮层下结构介导的。这种预测，当与上述标准相结合时，提供了一个独特的机会，以增加对补偿性成功和失败的理解，跨越认知技能的一个主要细分-外显和内隐推理。在拟议的实验中，年轻人和老年人将执行简单的类别学习任务，这些任务由PFC或皮层下区域介导。将使用功能性近红外光谱（fNIR）测量PFC血流，以测量与任务需求相关的激活变化的时间和持续时间。对于外显规则，补偿激活应该有助于学习过程中的表现。在学习内隐规则的过程中，PFC补偿应该尝试，但不成功，产生一个延长的活动增加期-卡贝萨和丹尼斯的标准预测的无效补偿的标志。我们计划从几个方面探索这一基本预测，比较年轻人和老年人，任务难度水平，双重任务要求，以及与大脑完整性相关的个体差异预测因子。这种方法对于预测正常的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.