A Compensatory Functional Neuroanatomy of ADHD

描述(由申请人提供)：工作记忆障碍会给ADHD患者的学术、社交和职业活动带来困难。这项应用的总体假设是，ADHD患者在执行工作记忆任务时，神经系统发生了变化。这种改变的系统是执行系统受损的结果，执行系统受到前扣带回(ACC)和前额叶皮质(PFC)的辅助。执行功能受损会削弱招募支持工作记忆的辅助大脑区域和策略的能力。功能成像技术为我们提供了了解这些策略的神经基础的窗口。我们的成像数据表明，ADHD患者的语音排练策略及其所在的大脑区域受到了损害。然而，视觉空间策略及其相关的神经网络是完好无损的。限制使用语音和视觉策略可能会增加错误和处理速度。我们提出了以下目的来研究ADHD儿童的工作记忆：1)使用减法技术结合视觉序列加法任务来确定ADHD儿童工作记忆缺陷的神经相关性；2)确定在工作记忆任务中产生的大胆信号变化与行为(反应时间、错误类型；课堂评分)之间的关系；以及3)比较ADHD儿童及其组合亚型和注意力不集中亚型，以确定与每种类型相关联的工作记忆神经策略。我们假设，ADHD混合型受试者使用主要的视觉-空间策略来执行工作记忆系列加法任务的一般模式将会出现。在自然环境下，ADHD功能障碍的程度预计与视觉空间激活呈正相关，与前额叶皮质激活呈负相关。我们预测注意缺陷多动障碍类型在任务执行过程中不会表现出与混合型类型相同的视觉空间激活水平。相反，在正常对照儿童激活的相同区域，它们的激活程度会降低。更好地理解ADHD所使用的策略对ADHD儿童如何学习和治疗目标具有潜在的教育意义。

DESCRIPTION (provided by applicant): Impairments in working memory create difficulties for individuals with ADHD in their academic, social, and occupational activities. The overall hypothesis of this application is that individuals with ADHD engage an altered neural system when performing working memory tasks. This altered system arises as a consequence of an impaired executive system, which is subserved by the anterior cingulate (ACC) and prefrontal cortical regions (PFC). Impaired executive functioning weakens the ability to recruit subsidiary brain regions and strategies that support working memory. Functional imaging techniques give us a window into the neural basis of those strategies. Our imaging data suggest that phonological rehearsal strategies and the brain regions subserving them are impaired in ADHD. Visual-spatial strategies and their associated neural networks, are however, intact. Limited access to both phonological and visual strategies may increase errors and processing speed. We propose the following aims to investigate working memory in children with ADHD: 1) Define the neural correlates of working memory deficits in ADHD children using subtraction techniques in conjunction with a visual serial addition task; 2) Identify the relationship between BOLD signal changes generated during a working memory task and behavior (response time, error type; classroom ratings); and 3) Compare ADHD children with the Combined subtype to Inattentive subtype to identify the working memory neural strategies associated with each. We hypothesize that a general pattern will emerge in which ADHD combined type subjects use a predominantly visual-spatial strategy to perform a working memory serial addition task. The degree of ADHD dysfunction in the natural setting is expected to positively relate to visualspatial activation and negatively to prefrontal cortical activation. We predict that the ADHD-inattentive type will not exhibit the same level of visual-spatial activation during task performance as the Combined-type. Instead they will exhibit reduced activation in the same regions activated by the normal control children. A better understanding of strategies used in ADHD has potential educational implications for how children with ADHD learn and targets for treatment.