A Compensatory Functional Neuroanatomy of ADHD

描述（由申请人提供）：工作记忆的损伤给多动症患者的学业、社交和职业活动带来困难。这一应用的总体假设是，患有多动症的个体在执行工作记忆任务时，神经系统发生了改变。这种改变的系统是由前扣带（ACC）和前额皮质区（PFC）的执行系统受损引起的。执行功能受损会削弱招募辅助大脑区域和支持工作记忆的策略的能力。功能成像技术为我们了解这些策略的神经基础提供了一个窗口。我们的成像数据表明，语音排练策略和为其服务的大脑区域在ADHD中受损。然而，视觉空间策略及其相关的神经网络却完好无损。对语音和视觉策略的限制可能会增加错误和处理速度。本研究旨在研究ADHD儿童的工作记忆：1)利用减法技术结合视觉连续加法任务，明确ADHD儿童工作记忆缺陷的神经相关因素；2)识别工作记忆任务中产生的BOLD信号变化与行为（反应时间、错误类型、课堂评分）之间的关系；3)比较组合型和注意力不集中型ADHD儿童的工作记忆神经策略。我们假设一个普遍的模式将会出现，ADHD合并型受试者主要使用视觉空间策略来执行工作记忆系列加法任务。在自然环境下，ADHD功能障碍的程度与视觉空间激活呈正相关，与前额皮质激活负相关。我们预测注意力不集中型多动症在任务执行过程中不会表现出与复合型多动症相同的视觉空间激活水平。相反，他们会在正常对照儿童激活的相同区域表现出减少的激活。对ADHD治疗策略的更好理解对ADHD儿童的学习方式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.