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

点击翻译按钮获取中文摘要

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.