Correcting Motion and Physiological Noise: key barriers in resting state fMRI

描述(申请人提供)：静息状态功能连接磁共振成像(RS-fcMRI)已经成为绘制大脑功能组织图的一种关键的非侵入性技术。在神经或精神障碍中，这种组织或功能连接经常发生改变。RS-fcMRI有望产生重大的临床影响，因为大量功能相关的大脑网络可以在不要求受试者执行任何特定任务的情况下进行表征。这一点很重要，因为许多临床或研究人群要么受到他们在MRI扫描仪中执行任务的能力的限制，要么在任务表现上存在差异。此外，rS-fcMRI在确定许多精神和神经疾病的基础上有着很大的希望。然而，一个关键的问题是，受试者的运动和生理噪音(特别是呼吸深度和呼吸频率的变化)可能会导致大脑的各个区域看起来好像在功能上是相连的。虽然已经开发了许多技术来校正运动和生理噪声，但目前还没有关于应用哪些处理步骤的共识。更重要的是，即使有了可用的技术，运动和生理噪音造成的假阳性仍然存在。因此，尚不清楚在不同时间或不同受试者之间观察到的功能连接性差异是真正的神经元起源，还是仅仅是受试者运动或生理噪音差异的结果。这对rs-fcmri的未来应用构成了一个重大障碍。该研究的目的是减少受试者头部运动和生理噪声的影响，以提高绘制脑功能连接图的准确性和一致性。为了实现这一目标，提出了两个互补的策略：1)开发一种对运动和生理波动更稳健的新的MRI采集方案；以及2)开发新的处理方法来更好地建模和解释运动和呼吸引起的伪影。这些新的处理技术包括使用从外部获得的信息的方法，以及适用于现有数据集的方法，鉴于已经获得的大量数据，这一点很重要。这项研究的预期结果是，在绘制不同时间和不同受试者之间大脑功能组织差异图谱的能力方面有了显着改善。这一信息将对目前和未来数百项RS-fcMRI研究产生重大影响。这是在临床研究和研究中成功使用静息状态功能连接的关键一步，这些研究旨在提高我们对大脑发育的理解，精神和神经疾病中大脑组织的紊乱，以及导致后来的精神病理学(也是其风险因素)的发展轨迹的改变。

DESCRIPTION (provided by applicant): Resting-state functional connectivity MRI (rs-fcMRI) has emerged as a key noninvasive technique for mapping the functional organization of the brain. This organization, or functional connectivity, is often altered in neurological or mental disorders. Rs-fcMRI is poised to have a significant clinical impact, since a large number of functionally relevant brain networks can be characterized without requiring the subject to perform any specific tasks. This is important, since many clinical or research populations are either limited by their ability to perform tasks in the MRI scanner or have differences in task performance. In addition, rs-fcMRI holds great promise for determining the basis of many mental and neurological disorders. However, a critical problem is that subject motion and physiological noise (from variations in respiration depth and rate in particular) can cause regions of the brain to appear as if they are functionally connected. While a number of techniques have been developed to correct for motion and physiological noise, there is currently no consensus on which processing steps to apply. More importantly, even with available techniques, false positives resulting from motion and physiological noise remain. It is therefore unclear whether observed differences in functional connectivity across time or between subjects are truly neuronal in origin, or merely the result of differences in subject motion or physiological noise. This presents a significant barrier to the future utility of rs-fcMRI. The goal of the proposed research is to reduce the influence of subject head motion and physiological noise in order to improve the accuracy and consistency of mapping functional brain connectivity. Two complementary strategies are proposed to achieve this goal: 1) the development of a novel MRI acquisition scheme that is more robust to motion and physiological fluctuations; and 2) the development of new processing methods to better model and account for motion and respiration induced artifacts. These new processing techniques consist of methods that use externally-acquired information, as well as methods that are applicable to existing datasets, which is important given the wealth of data already acquired. The expected outcome of this study is a significant improvement in the ability to map differences in the functional organization of the brain across time and between subjects. This information will have a significant impact on hundreds of current and future rs- fcMRI studies. It is a critical step towards the successful use of resting-state functional connectivity in clinical investigations, as well as research studies aimed at improving our understanding of brain development, the disrupted brain organization in mental and neurological disorders, and the alterations in developmental trajectories that lead to (and are a risk factor for) later psychopathology.