Application of multi-distance diffuse optical tomography to the study of human br

描述（由申请人提供）：该项目探索了一种用于成像人脑功能的方法的进步，该方法基于近红外光如何通过大脑扩散的变化的测量（扩散光学断层扫描，DOT）。这种方法是特别有用的调查的时间过程中快速的大脑现象，如神经活动，和功能性血液动力学反应，神经元活动响应于在认知任务期间提供的刺激。DOT可以应用于人群（如小孩或患有幽闭恐怖症或携带金属设备的人），这些人无法使用其他脑成像技术进行研究。它也可以同时使用的标准方法，如功能性磁共振成像（fMRI）和事件相关脑电位（ERP）提供了一个重要的桥梁，了解这些方法的生理基础。重要的是，DOT信号可能在大量的研究和临床应用中是有用的，包括研究正常和异常的大脑活动， 精神病理学、认知老化和痴呆、发育和由于脑血管问题，以及从新生儿到老年人的脑血管疾病的研究和诊断。这一技术目前的局限性是，以其目前的形式，它只能衡量基线水平的变化。为了将功能数据与特定的大脑结构相关联，用户必须依赖于头表面特征或独立收集的结构MR记录。在这里，我们探讨了一种方法，称为“多距离”的方法，以产生在整个皮质表面的扩散参数的绝对测量的应用。这些测量结果可用于显示富含血红蛋白的解剖结构（如静脉窦），这些结构可用作配准的有用解剖标志。重要的是，可以在记录功能DOT数据的同时收集这种结构信息。该提案将探讨这些信息的可靠性，以及如何将其用于精确地将功能测量与解剖学大脑结构相结合。这项拟议中的研究还将探索大脑对近红外光的透明度如何随着年龄的增长而变化。初步数据表明，与年龄相关的变化很大，老年人的大脑透明度明显高于年轻人。这种差异可能反映了脑血管化和/或皮质萎缩的变化。拟议的研究将探索这些因素的相关性，这可能使这种方法成为以非侵入性方式研究大脑皮层健康状况的有用工具。光漫射参数的绝对测量还允许对由于认知任务期间特定脑区的激活而引起的功能DOT效应进行更定量的研究，以及它们在不同人群中如何随年龄（以及原则上，发育和病理学）而变化。本研究将比较不同的方法来获得这些功能图像的可靠性，有效性和信噪比。

DESCRIPTION (provided by applicant): This project explores advancements in a method for imaging the function of the human brain, based on the measurements of changes in how near-infrared light diffuses through the brain (Diffuse Optical Tomography, DOT). This method is particularly useful to investigate the time course of rapid brain phenomena, such as neural activity, and the functional hemodynamic responses that follow neuronal activity in response to stimuli delivered during cognitive tasks. DOT can be applied to populations (such as small children or people who are claustrophobic or bearing metallic devices), who cannot be easily studied using other brain imaging technologies. It can also be concurrently used with standard methods such as functional magnetic resonance imaging (fMRI) and event-related brain potentials (ERPs) providing an important bridge for the understanding of the physiology underlying these methods. Importantly, DOT signals can potentially be useful in a large number of research and clinical applications, including the study of normal and abnormal brain activity in psychopathology, cognitive aging and dementia, development, and as a result of vascular brain problems, as well as for the study and diagnosis of cerebrovascular diseases from newborns to the elderly. A current limitation of this technique is that, in its current form, it only measures changes from a baseline level. In order to relate the functional data to particular brain structure, users have to rely on head-surface features or independently-collected structural MR-recordings. Here we explore the application of a methodology, called "multi- distance" approach, to generate absolute measurements of diffusion parameters over the entire cortical surface. These measurements can be used to reveal anatomical structures rich in hemoglobin (such as the venous sinuses), which can serve as useful anatomical landmarks for coregistration. Importantly, this structural information can be collected while recording the functional DOT data. The proposal will explore how reliable this information is, and how it can be used to precisely co-register the functional measures to anatomical brain structures. The proposed research will also explore how the transparency of the brain to near-infrared light changes with age. Preliminary data suggest strong age-related variations, with older adults showing significantly more brain transparency than younger adults. This difference may reflect changes in brain vascularization and/or cortical atrophy. The proposed research will explore the relevance of these factors, which may render this approach a useful tool for studying the health status of the cortex in a non-invasive manner. The absolute measurements of the light diffusion parameters also allows for a more quantitative study of functional DOT effects due to the activation of specific brain areas during cognitive tasks, and how they vary in different populations, as a function of age (and in principle, development and pathology). The proposed research will compare different methods for obtaining these functional images in term of their reliability, validity and signal-to-noise ratio.