Hierarchical control of sequential skills: Using EEG to decode the underlying representations

许多最有趣的人类活动都是由行为的基本构建块被组织成适当的序列而产生的。例如，口语包括将单个音节组合成单词和句子；而演奏音乐则需要将音符组合成旋律。头脑必须根据结合基本元素的层次结构来表现这些活动。由于神经系统疾病或衰老导致的执行这种结构的能力缺陷，可能会对现实世界的功能产生广泛的影响。目前，人们对能够实现这些顺序技能的心理表征知之甚少，也不清楚这些表征的中断如何导致流利的顺序表现的缺陷。这个项目开发了新的方法来追踪这些心理表征，使用记录在头皮上的电生理信号（EEG）。这些方法将使我们能够精确定位个体和年龄相关差异的确切来源，并为疾病或脑损伤导致的缺陷的起源提供初步线索。该项目为本科生和研究生提供复杂的脑成像和数据分析技术方面的培训和教育机会，并为贫困的高中生提供科学教育内容。长期以来，认知科学家一直认为，支持有序行为的关键的、分层组织的结构依赖于一组特殊的心理表征，这些心理表征将复杂的序列组织成更小的部分（通常称为块），或者标记块中的位置。然而，由于它们的抽象性，从经验上追踪这些隐藏表征是非常困难的。在这个项目中测试的中心假设是，有节奏的电生理信号包含了关于这些心理表征在给定时间点被激活的强烈程度的可靠信息。计划中的实验将检验新的、基于脑电图的跟踪心理表征方法的有效性和稳健性。个体实验将确定位置或块是如何准确表征的，并将测试关于个体或成人认知资源（例如，工作记忆容量）的年龄相关差异如何影响顺序表征的特定假设。该项目将为研究人员提供关于如何处理顺序信息的完善理论，并更广泛地提供一套新的分析工具来表征复杂的认知表现。

Many of the most interesting human activities result from basic building blocks of behavior being structured into appropriate sequences. For example, speaking involves the combination of individual syllables into words and sentences; while, performing music involves the combination of notes into melody. The mind must represent these activities in terms of the hierarchical structures that combine the basic elements. Deficits in the ability to implement such structures, due to neurological disorders or aging, can have wide-ranging consequences for real-world functioning. Little is currently known about the mental representations that enable these sequential skills, or about how deficits in fluent sequential performance arise from disruptions to these representations. This project develops new methods for tracking these mental representations using electrophysiological signals recorded at the scalp (EEG). These methods will allow the pinpointing of the exact sources of individual and age-related differences and provide initial hints for the origin of deficits due to disease or brain insults. The project provides training and educational opportunities in sophisticated brain-imaging and data-analytic techniques for undergraduate and graduate students and contains a science-education component for underprivileged high-school students.Cognitive scientists have long assumed that the critical, hierarchically-organized structures that support sequenced behaviors rely on a special set of mental representations that organize complex sequences into smaller parts (often referred to as chunks), or that mark the position within a chunk. Yet, because of their abstract nature, it has been very difficult to empirically track these hidden representations. The central hypothesis tested in this project is that rhythmic, electrophysiological signals contain robust information about how strongly these mental representations are activated at a given point in time. The planned experiments will examine the validity and robustness of new, EEG-based methods of tracking mental representations. Individual experiments will determine how exactly positions or chunks are represented and will test specific hypotheses about how individual or adult, age-related differences in cognitive resources (e.g., working-memory capacity) affect sequential representations. This project will equip researchers with refined theories about how sequential information is processed, and more generally with a novel set of analytic tools to characterize complex, cognitive performance.