INTEGRATING BRAIN IMAGING AND GENETIC ANALYSIS OF ADHD

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。该提案旨在利用全脑结构和功能磁共振成像（fMRI）检查注意缺陷多动障碍（ADHD）中执行控制缺陷的功能和结构神经病理学（以抑制性控制、工作记忆和注意力集转换为指标）。据推测，由于多巴胺能功能异常，ADHD患者执行控制的前额叶-纹状体-小脑回路功能失调。我们将对这一假设的两个预测进行检验：(1)fMRI将揭示ADHD儿童在抑制控制（Exp 2）、工作记忆（Exp 3）和注意集转换（Exp 4）期间前额叶-纹状体-小脑区域的功能激活将异常（相对于对照组），并将通过给药哌甲酯使ADHD儿童正常化。实验2-4的样本将包括48名9-11岁的混合型ADHD儿童（24名女孩和24名男孩）和48名年龄、性别和智商匹配的健康儿童。(2)多巴胺转运蛋白基因型（DAT1）可能影响ADHD患者前额叶纹状体区域对哌甲酯的功能反应。实验1的样本为36例混合型ADHD儿童（480bp-10/10、480bp-10/9、440bp-9/9各12例）。这些ADHD受试者是CNMC正在进行的一项药物发生研究的参与者，该研究发现哌醋甲酯对480bp携带者的临床疗效优于440bp携带者。我们有一个独特的机会来检查这些多动症儿童在抑制控制期间对哌甲酯的功能性大脑反应。在所有的实验中，fMRI将对多动症儿童在给予哌甲酯和安慰剂的情况下进行；对照儿童（实验2-4）不使用哌甲酯成像。此外，高分辨率结构成像将用于检查在fMRI中激活的区域在ADHD亚组和对照组之间的灰质体积是否不同。我们的建议的新特点包括：1)检查相同ADHD和对照儿童的大脑结构和功能差异；2)检查ADHD儿童对哌醋甲酯的功能性脑反应，其中哌醋甲酯的临床疗效因DAT1基因型而异。检查这种基因型-表型关系将阐明ADHD的潜在病因和神经病理生理学，这将有助于诊断、早期干预和治疗计划。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The proposal aims to examine functional and structural neuropathology underlying deficits of executive control (indexed by inhibitory control, working memory, and attentional set switching, in Attenton Deficit Hyperactivity Disorder (ADHD) using whole-brain structural and functional magnetic resonance imaging (fMRI). It is hypothesized that prefrontal-striatal-cerebellar circuitry underlying executive control is dysfunctional in ADHD due to abnormal dopaminergic function. We will test two predictions of this hypothesis - (1) fMRI will reveal that the functional activation in prefrontal-striatal-cerebellar regions during inhibitory control (Exp 2), working memory (Exp 3), and attentional set switching (Exp 4) will be abnormal in ADHD children (relative to control children) and will be normalized by the administration of methylphenidate in ADHD children. Sample for Experiments 2-4 will include 48 9-11 year old Combined-type ADHD children (24 girls and 24 boys) and 48 age, gender, and IQ-matched healthy children. (2) Functional response to methylphenidate in prefrontal-striatal regions underlying inhibitory control in ADHD will be influenced by dopamine transporter genotype (DAT1) (Exp 1). Sample for Experiment 1 will include 36 combined-type ADHD children (12 carriers of 480bp-10/10, 480bp-10/9, 440bp-9/9, each). These ADHD subjects were participants in an ongoing pharmocogenetic study at CNMC that found superior clinical efficacy of methylphenidate in carriers of 480bp than 440bp. We have the unique opportunity to examine the functional brain response to methylphenidate during inhibitory control in those same ADHD children. In al experiments, fMRI will be performed on ADHD children with administration of methylphenidate and placebo; control children (in Experiments 2-4) will be imaged without methylphenidate. Further, high resolution structural imaging will be used to examine whether regions activated during fMRI differ in gray matter volume between ADHD subgroups and controls. Novel features of our proposal include: I) examination of structural and functional brain differences in the same ADHD and control children and ii) examination of the functional brain response to methylphenidate in ADHD children in whom clinical efficacy of methylphenidate varied by DAT1 genotype. Examination of such genotype-phenotype relationships will elucidate potential etiological factors and neuropathophysiology of ADHD that will be useful in diagnosis, early intervention, and treatment planning.