New approaches to the analysis of coordinated neuromagnetic source activity

分析协调神经磁源活动的新方法

• 批准号: 341562-2013
• 负责人: Ross, Bernhard
• 金额: $ 1.82万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=527360
• 关键词: New; approaches; analysis; coordinated; neuromagnetic

Historically, neuroscientists investigated which brain area is involved in specific functions of perception, cognition. However, generally the whole brain is engaged when we speak, think, or move. Thus current research focuses on how brain areas are connected. We can measure brain activity noninvasively with multiple electrodes attached to the scalp in electroencephalography (EEG) and many magnetic field sensors arranged around the head in magnetoencephalography (MEG). We compare the signals at two electrodes or MEG sensors and search for oscillations with common rhythms. Our hypothesis is that synchronous oscillation at two sensors indicates that the underlying neural populations interact with each other. With MEG we can localize the neural activity and apply the analysis of synchrony to neuromagnetic source activity. The results indicate with much higher precision, which brain areas are functional connected than the analysis of sensor data can provide. MEG source analysis is not always perfect, and the cortical sources cannot be separated entirely, specifically if they are located in close vicinity. Because of such limitation, the source signals may show apparent synchrony, which is not related to functional connectivity. To overcome the effects of spurious synchrony, we will develop a series of data analysis techniques, which indicate true functional coordination and are insensitive to effects of spreading source activity. From simulation studies we will learn about the properties of synchrony measures in MEG source data. We will analyze MEG data in studies of perception and cognition. For all studies we develop a solid hypothesis about the functionally relevant brain activity. Based on the physiological properties of the source signals we design our analysis strategy. Specifically we will employ measures like temporal changes in synchrony, the imaginary part of coherence, synchrony between spectral components of the brain activity, statistics of phase resets, changes in stimulus-induced oscillations, and measures from nonlinear dynamics, which are not affected by limitations in the source analysis. The results will allow new and improved applications in basic research and clinical diagnostics.

历史上，神经科学家研究了哪些大脑区域参与感知、认知的特定功能。然而，当我们说话、思考或移动时，通常整个大脑都会参与其中。因此，当前的研究重点是大脑区域如何连接。我们可以通过脑电图 (EEG) 中连接到头皮的多个电极以及脑磁图 (MEG) 中排列在头部周围的许多磁场传感器来无创地测量大脑活动。我们比较两个电极或 MEG 传感器的信号，并寻找具有共同节奏的振荡。我们的假设是，两个传感器的同步振荡表明潜在的神经群体相互作用。通过 MEG，我们可以定位神经活动并将同步分析应用于神经磁源活动。结果表明，与传感器数据分析相比，哪些大脑区域具有功能连接的精度要高得多。 MEG 源分析并不总是完美的，并且皮质源无法完全分离，特别是如果它们位于附近。由于这种限制，源信号可能表现出明显的同步性，这与功能连接性无关。为了克服虚假同步的影响，我们将开发一系列数据分析技术，这些技术表明真正的功能协调并且对传播源活动的影响不敏感。通过模拟研究，我们将了解 MEG 源数据中同步测量的属性。我们将在感知和认知研究中分析脑磁图数据。对于所有研究，我们都对功能相关的大脑活动提出了可靠的假设。根据源信号的生理特性，我们设计了分析策略。具体来说，我们将采用同步时间变化、相干性虚部、大脑活动频谱成分之间的同步、相位重置统计、刺激引起的振荡变化以及非线性动力学测量等测量，这些测量不受源分析限制的影响。这些结果将在基础研究和临床诊断方面带来新的和改进的应用。