Anatomical connections subserving the default mode network

描述(申请人提供)：默认模式网络(DMN)是一组大脑区域，在休息时持续激活，在任务执行期间停用。DMN的活性在许多神经和精神疾病中都是异常的，包括严重抑郁障碍(MDD)和药物成瘾。DMN的两个主要部分是内侧前额叶皮质(MPFC)和后内侧皮质(PMC)，这两个区域在空间上相距很远，具有不同的规范功能。虽然有一些证据表明这些大脑皮层区域之间有直接联系，但人们对它们的细节以及它们如何将网络作为一个整体联系在一起知之甚少。我假设DMN由特定的中枢亚区连接在一起，这些亚区包含来自多个DMN区域的汇聚连接，扣带束和内囊是这个网络的主要连接白质束。因此，这项提议的目的是描绘mPFC和PMC之间的解剖连接和通路如何使它们作为一个网络运行。结合传统的解剖学技术和扩散磁共振成像(DMRI)，我将确定DMN背后的联系。定义这些特定的DMN连接将建立服务于神经成像结果的电路。这一基本知识是基础，也是了解疾病中DMN变化的第一步。DMN内的功能连接可能来自直接的解剖联系，间接的联系，或两者的某种组合。这笔赠款的第一个总体目标是勾勒出多边基金和私营部门委员会分区域之间的直接和间接联系，以寻找潜在的汇聚联系的区域。此外，dMRI已经发现了精神障碍，包括MDD和成瘾，白质通路中的特定异常可能与DMN结构有关。这些异常可能反映了特定的 关系。然而，穿过白质束中任何给定位置的纤维仍然未知。第二和第三个目标是利用示踪和dMRI方法建立连接DMN结构的白质通路。这将把dMRI和解剖追踪联系起来，测试dMRI的有效性，并为如何解释其结果提供指南。

DESCRIPTION (provided by applicant): The default mode network (DMN) is a set of brain regions consistently activated at rest and deactivated during task performance. DMN activity is abnormal in many neurological and psychiatric disorders, including major depressive disorder (MDD) and drug addiction. The two main parts of the DMN are the medial prefrontal cortex (mPFC) and posteromedial cortex (PMC), two areas that are spatially distant and have distinct canonical functions. While there is some evidence of direct connections between these general cortical areas, little is known about their specifics and how they link the network together as a whole. I hypothesize that the DMN is linked together by specific hub subareas that contain converging connections from multiple DMN regions, and the cingulum bundle and the internal capsule are the major connecting white matter bundles for this network. Thus, the goal of this proposal is to delineate how anatomical connections and pathways between mPFC and PMC allow them to operate as a network. Combining traditional anatomical techniques with diffusion magnetic resonance imaging (dMRI), I will determine the connections that underlie the DMN. Defining these specific DMN connections will establish the circuitry subserving neuroimaging results. This basic knowledge is fundamental and is the first step in understanding the changes in the DMN in disease. Functional connectivity within the DMN may result from direct anatomical links, indirect ones, or some combination of both. The first overall aim of this grant i to delineate the direct and indirect connections between subregions of the mPFC and PMC to find potential zones of converging connections. Furthermore, dMRI has identified psychiatric disorders, including MDD and addiction, with specific abnormalities within white matter pathways that likely link DMN structures. These abnormalities likely reflect disruption of specific connections. However, the fibers traveling through any given location within a white matter bundle remain unknown. The second and third aims are to establish white matter pathways that connect DMN structures using tracing and dMRI methods. This will link dMRI and anatomical tract-tracing, testing the validity of dMRI and providing a guide for how to interpret its results.