Characterizing the functional contribution of white matter systems within distributed neural networks

了解工作中的大脑是科学技术进步中一个快速增长的领域。考虑到我们最珍视的高级心理功能，如语言和记忆，依赖于对大脑回路的精细、复杂的处理，这种快速进步的原因是完全有道理的。这些大脑回路以分布式网络的形式存在，随着信息的处理而动态激活。近年来，我们在非侵入性地窥视大脑内部并观察这些网络的各个方面处理信息和形成思想的能力方面取得了重大技术进步；这一直是当前NSERC资助的研究计划的主要重点。之前的工作集中在更好地理解分布式网络中的“激活”概念--这是向更多地了解高级心理功能迈出的基本一步。在这一过程中，发现了一个缺失的环节。大脑可以分为两种大致相等的组织类型：灰质和白质。在考虑分布式网络时，前者(灰质)可以被认为是点，而后者(白质)可以被认为是连接这些点的线。缺失的一环：大脑成像“激活”只能看到点。这实际上只代表了画面的50%。如果不能隔离连接这些点的活动线路，识别这些重要的分布式网络即使不是不可能，也是困难的。当前研究计划的目标是识别白质中活跃的连接(线)，然后开始非侵入性地了解这些动态网络。这项研究扩展了脑扫描的进展，使用了功能磁共振成像(FMRI)和相关的基于MRI的技术。我的团队在使用功能磁共振应用程序检测大脑中的白质激活方面处于领先地位。通过一系列实验，已经有可能证明白质激活会导致特定的大脑连接(主要是胼胝体)。为了将这一结果推广到可以充分推广和利用的广泛应用中，下一步是更好地表征白质激活的生理、物理和分析性质。为实现这一目标，计划开展短期项目。一旦完成，长期目标是确定支持更高级别信息处理的候选网络。将活跃的连接添加到图像中，我们将通过结合额外的脑波技术(如脑磁图)来检查这些网络跨空间和时间域的激活动力学。结果和意义将通过提高我们对大脑在高水平功能和功能障碍期间工作的理解来展示。通过改善目前对大脑工作状态的了解，这项研究将为未来的一系列进展奠定基础，以帮助三分之一的加拿大人在一生中受到与大脑相关的疾病的影响。

Understanding the brain at work is a rapidly growing area of science and technology advancement. The reasons for this rapid advance make perfect sense when considering that our most prized higher-level mental functions, like language and memory, rely on finely tuned, complex processing of brain circuits. These brain circuits exist as distributed networks that are dynamically activated as information is processed. In recent years, there have been major technological advances in our ability to non-invasively peer inside the brain and watch aspects of these networks process information and form thoughts; this has been the primary focus of the current NSERC-funded research program. Prior work has concentrated on a better understanding of the concept of “activation” in distributed networks – a fundamental step towards learning more about higher mental functions. In the process, a missing link was identified. The brain can be divided into two, approximately equal, types of tissue: gray matter and white matter. When considering distributed networks, the former (gray matter) can be thought of as the dots and the latter (white matter) as the lines that connect the dots. The missing link: brain imaging “activation” sees only the dots. This effectively represents only 50% of the picture. Without being able to isolate the active lines that connect the dots, it is difficult, if not impossible, to identify these vital distributed networks. The objective of the current research program focuses on identifying active connections (the lines) in white matter and then beginning to understand these dynamic networks, non-invasively. The research expands on progress with brain scans, using functional magnetic resonance imaging (fMRI) and related MRI-based techniques. My group has led in the use of fMRI applications to detect white matter activation in the brain. Through a series of experiments, it has been possible to demonstrate that white matter activation results in specific brain connections (primarily the corpus callosum). In order to move this result to wide spread applications that can be fully generalized and utilized, the next step is to better characterize the physiological, physical, and analytical nature of white matter activation. Short-term projects are planned to achieve this goal. Once accomplished, the longer-term objective is to identify candidate networks that support higher-level information processing. With the active connections added to the picture, we will examine the activation dynamics of these networks across spatial and temporal domains by incorporating additional brain wave technologies (such as magnetoencephalography). Outcomes and significance will be demonstrated by improving our understanding of the brain at work during high-level function and dysfunction. By improving current knowledge of the brain at work, the research will lay the foundation for a host of future advances to help the one in three Canadians who are affected by brain-related conditions during their lives.