Cognitive control and the functional organization of frontal cortex

描述(申请人提供)：这个研究项目的目标是促进我们对额叶皮质的功能组织以及额叶区域之间的相互作用允许内部控制思想和行动的方式的理解，这种能力被称为认知控制。所提出的实验验证了这一假设，即额叶的嘴-尾轴包括一个加工层次，在这个层次上，更多的前部区域支持涉及逐渐更抽象的目标、计划和动作表征的认知控制。首先，一组fMRI实验，使用析因逻辑，试图指定抽象的维度，这些维度定义了额叶吻尾轴上的区域差异。一些实验已经证明，当认知控制涉及更抽象的表征时，沿着嘴-尾轴的功能梯度。然而，这些实验在抽象的定义上有所不同，包括域一般性、时间抽象和规则复杂性。虽然抽象的这些维度不是相互排斥的，但在受控的情况下，它们也可以独立地变化。因此，第一组fMRI实验利用这种独立性来提供更明确的抽象定义，因为它与额叶功能有关。其次，分层系统要求上级处理器可以调制下级处理器，但反之亦然。转化为额叶层级，这种不对称性预测，额叶皮质给定区域的控制处理应该直接影响到其轨迹后面但不是前面的区域。因此，一系列fMRI实验将使用有效的连接性分析来检验(A)前额区的认知控制加工是否可以调节后额区的加工，(B)后额区的认知控制加工是否会影响前额区的同时控制加工。第三，一组实验将研究在学习和适应分层结构的规则集过程中的额叶功能。一般而言，层次结构是支持新任务学习的有用结构，因为它们可以在多个抽象水平上表示相同的信息，因此可以为先前知识的应用提供接入点，例如通过类比。因此，一组实验测试了假设的额叶层次是否反映了在学习新规则集、将学习转移到新任务以及将转换规则应用于现有规则集的过程中的这种动态。因此，这个研究项目跨越了它的目标，通过测试三类不同的预测来三角划分额叶等级组织的假设，每一类预测都来自于等级系统的假设。

DESCRIPTION (provided by applicant): The goal of this research program is to advance our understanding of the functional organization of frontal cortex and the ways in which interactions among frontal regions permit internal control of thought and action, an ability termed cognitive control. The proposed experiments test the hypothesis that the rostro-caudal axis of the frontal lobes comprises a processing hierarchy whereby more anterior regions support cognitive control involving progressively more abstract goals, plans, and action representations. First, a set of fMRI experiments, using factorial logic, seek to specify the dimensions of abstraction that define regional differences along the rostro-caudal axis of the frontal lobes. Several experiments have demonstrated a functional gradient along the rostro-caudal axis as cognitive control involves more abstract representations. However, these experiments have differed in their definition of abstraction, including domain generality, temporal abstraction, and rule complexity. Though these dimensions of abstraction are not mutually exclusive, they may also be independently varied under controlled circumstances. Thus, the first set of fMRI experiments take advantage of this independence to provide a more explicit definition of abstraction as it relates to frontal lobe function. Second, a hierarchical system requires that superordinate processors can modulate subordinate processors but not vice versa. Translated to a frontal hierarchy, this asymmetry predicts that control processing by a given region of the frontal cortex should directly influence regions posterior to but not anterior to its locus. Thus, a line fMRI experiments will use effective connectivity analysis to test whether (a) cognitive control processing in anterior frontal regions can modulate processing in posterior frontal regions, (b) whether cognitive control processing in posterior frontal regions can affect concurrent control processing by anterior frontal regions. Third, a set of experiments will investigate frontal lobe function during learning and adaptation of hierarchically structured rule sets. In general, hierarchies are useful structures for supporting learning of novel tasks because they can represent the same information at multiple levels of abstraction and so can provide access points for the application of prior knowledge, such as through analogy. Thus, a set of experiments test whether the putative frontal lobe hierarchy reflects such dynamics during learning of novel rule sets, the transfer of learning to new tasks, and the application of transformational rules to existing rule sets. Hence, across its aims, this program of research triangulates the hypothesis of a hierarchical organization of the frontal lobe by testing three different classes of predictions that each arises from an assumption of a hierarchical system.