Proj 2: Learning of executive fnct. (143-169)

这项拟议的研究的首要目标是了解不同大脑区域在大脑中的具体作用 执行功能的学习，通过经验测试和进一步开发基于生物的计算 前额叶皮质及相关皮质下系统的模型(包括基底节和 中脑多巴胺能核)。我们侧重于两个具体问题：(A)学习抽象的、类似规则的表征 在前额叶皮质区域，这通过支持更好的泛化来支持灵活行为 新的环境；和(B)反馈驱动的学习机制，它塑造了自适应调制 根据我们的模型，前额叶执行功能由基底节表示。几个 这个计算建模框架的预测已经在不同的领域得到了成功测试 人群，包括帕金森氏症患者和ADHD患者，这两者都被认为与疾病有关 多巴胺能系统，因为它影响基底节和前额叶皮质。因此，该模型具有 对理解执行功能的神经基础的重要意义，两者在神经学上都是完整的 和无序的人口。 我们建议检验以下假设： 具体目标2.1：影响前额叶皮质表征学习的因素：首先，我们 在年轻人和儿童身上测试我们计算模型中的一组预测。例如, 分组训练应有助于发展抽象的、类似规则的表述，这在 支持或更好地概括到新的任务上下文。第二，因为抽象的程度 在我们的模型中，学习取决于主动维护的持续时间，不同的PFC区域可能是 按照相对抽象程度和相应的维护时长进行组织。我们 在模型中探索这一想法。 具体目标2.2：影响反馈学习的因素。我们提供了一种更直接的多巴胺能 事件相关电位信号对反馈信息(ERN)的调节作用 多巴胺D2受体激动剂/拮抗剂，它们应该对这些 根据我们的模型，信号。我们还测试了情绪诱导是否可以改变 反馈响应性，由ERP来衡量。最后，我们试图理清多个因素 协同执行功能和负性执行功能对执行功能任务学习的影响 儿童反馈学习研究。

The overarching goal of the proposed research is to understand the specific roles of different brain areas in the learning of executive function, by empirically testing and fur ther developing a biologically-based computational model of the prefrontal cor tex and associated subcor tical systems (including the basal ganglia and midbrain dopaminergic nuclei). We focus on two specific issues: (a) the learning of abstract, rule-like representations in prefrontal cor tical areas, which suppor t flexible behavior by enabling better generalization to novel circumstances; and (b) the mechanisms of feedback-driven learning, which shape the adaptive modulation of prefrontal executive function representations by the basal ganglia, according to our model. Several predictions from this computational modeling framework have already been successfully tested in diverse populations, including Parkinson's patients and people with ADHD, both of which are thought to involve disorders of the dopaminergic system as it affects the basal ganglia and prefrontal cor tex. Thus, this model has impor tant implications for understanding the neural basis of executive function, both in neurologically intact and disordered populations. We propose to test the following hypotheses: ¿ Specific Aim 2.1: Factors Affecting Learning of Representations in Prefrontal Cortex: First, we test in both young adults and children a set of predictions from our computational model. For example, blocked training should facilitate the development of abstract, rule-like representations, which in turn suppor t better generalization to novel task contexts. Second, because the degree of abstraction learning depends on the duration of active maintenance in our model, different regions of PFC may be organized according to relative degree of abstraction, and corresponding maintenance duration. We explore this idea in the model. ¿ Specific Aim 2.2: Factors Affecting Feedback Learning. We provide a more direct test of dopaminergic mediation of event-related potential signals responsive to feedback information (ERN) by administering dopamine D2 receptor agonists/antagonists, which should have dissociable effects on these signals according to our model. We also test whether mood induction can shift the balance of feedback responsiveness, as measured by ERP's. Finally, we attempt to disentangle multiple factors influencing learning of executive function tasks by using coordinated executive function and negative feedback learning studies in children.