Anomalous Motor Physiology In ADHD

注意力缺陷/多动障碍（ADHD）是一种高度流行的疾病，可导致家庭/社会关系以及在学校和职业中取得成功的能力的重大损害;然而，ADHD神经生物学的基本方面仍然知之甚少。异常的运动发育是一个一致的，但很少研究的特点，观察ADHD，可以提供深入了解的神经基础的障碍。ADHD儿童在定时重复和顺序运动方面不符合年龄规范，并且比年龄匹配的对照组表现出更大的运动溢出量。这些发现可以准确地将ADHD儿童与正常对照组和其他神经精神疾病儿童区分开来，表明ADHD与运动皮层抑制系统的异常有关。功能性磁共振成像（fMRI）和经颅磁刺激（TMS）可以定位和量化运动皮层内的抑制，因此特别适合于研究ADHD的运动抑制。我们假设ADHD儿童的神经运动异常与运动皮质的皮质内和半球间抑制不足有关。这一假设与ADHD的中枢缺陷是未能抑制或延迟行为反应的研究一致。我们使用功能磁共振成像和经颅磁刺激的初步研究表明，运动皮层抑制异常存在于ADHD儿童。这个项目的总体目标是调查与ADHD相关的运动异常的神经学基础。我们提出三个具体目标。在第一个目标中，我们将使用肌电图（EMG）和加速度计来测量溢出运动，这将使我们能够检测溢出测量与神经生理学和成像数据之间有意义的相关性。第二个目标将集中于使用TMS检查运动皮层抑制。第三个目标是评估简单手指运动过程中的fMRI激活模式，包括与溢出运动相关的激活模式。然后，我们将研究皮质抑制异常与多动症和注意力不集中的关系。这些研究的数据将对ADHD的神经生物学基础产生重要的见解，并为未来开发更有效的治疗方法奠定基础。

DESCRIPTION (provided by applicant): Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent disorder that can cause substantial impairment in family/social relationships and the ability to succeed in school and occupation; yet, fundamental aspects of the neurobiology of ADHD remain poorly understood. Anomalous motor development is a consistent, but infrequently studied characteristic observed with ADHD that can provide insight into the neurologic basis of the disorder. Children with ADHD fail to meet age-norms on timed repetitive and sequential movements and manifest a greater amount of motor overflow than age-matched controls. These findings, which can accurately distinguish ADHD children from normal controls and children with other neuropsychiatric disorders, suggest that ADHD is associated with abnormalities of motor cortex inhibitory systems. Functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) can localize and quantify inhibition within the motor cortex and thus are particularly suited to study motor inhibition in ADHD. We hypothesize that the neuromotor anomalies present in children with ADHD are associated with deficient intracortical and interhemispheric inhibition of the motor cortex. This hypothesis is consistent with studies suggesting that the central deficit of ADHD is a failure to inhibit or delay a behavioral response. Our preliminary studies using both fMRI and TMS suggest that abnormalities of motor cortex inhibition are present in children with ADHD. The overall goal of this project is to investigate the neurologic basis of motor anomalies associated with ADHD. We propose three specific aims. In the first aim we will measure overflow movements using electromyography (EMG) and accelerometry, which will allow us to detect meaningful correlations between overflow measurements and neurophysiologic and imaging data. The second aim will focus on examining motor cortex inhibition using TMS. The third aim will assess patterns of fMRI activation during simple finger movements, including activation patterns associated with overflow movements. We will then examine the relationship between abnormalities of cortical inhibition and measures of hyperactivity and inattention. The data from these studies will yield critical insights into the neurobiological basis of ADHD and will also set the stage for future development of more effective therapies for this population.