Multiscale and wavelet based signal processing for electrophysiological and optical brain imaging

医学成像，特别是功能神经成像，是生物医学中最具活力的科学技术领域之一。在头皮上获得的生物电测量对于应对神经疾病的挑战以及设计能够解码神经活动的技术至关重要，例如，为残疾人设计控制系统。自从理查德·卡顿(Richard Caton)(1875年)首次记录了电势的测量以来，电生理学--研究生物有机体的电特性--已经取得了长足的发展，并因此设计出了一些非常有用的工具来测量神经活动。在过去的30年里，其中一项技术--脑磁图(测量神经活动产生的磁场)与另一种工具--脑电图术相结合，提供了大脑活动的生物电磁特征。第三种技术基于红外光在脑组织中的扩散和吸收，使测量神经活动引起的血液动力学变化成为可能。在临床环境中，例如癫痫，或者在神经科学和认知科学中，在特定情况下研究大脑功能，比如在睡眠中，或者当大脑参与涉及感知或记忆的任务时，这种测量对于评估病理学是必不可少的。这项研究计划专注于数字工具，这些工具使在计算机上处理光学和生物电磁测量成为可能，以便可视化构成大脑活动的复杂和动态网络中涉及的皮质区域。我们还将研究在手术框架内评估的癫痫患者的颅内电生理测量，通过研究发生的快速振荡的爆发，并且至少其中一些似乎与病理有关。从这些信号在头部表面的光谱复杂性的角度来描述它们的特征是这项研究计划的挑战之一，该研究计划旨在开发分析“工作的人脑”的新方法。

Medical imaging, and functional neuroimaging in particular, is one of the most dynamic of the scientific and technological fields in biomedical. Bioelectrical measurements acquired on the scalp of the head are vitally important in terms of responding to the challenges of neurological illness, as well as for designing technologies capable of decoding neural activity, control systems for the disabled, for example. Electrophysiology, the study of the electrical properties of biological organisms, has developed considerably since the first measurements of electrical potential were recorded by Richard Caton (1875), and some very useful tools for measuring neural activity have been devised as a result. Over the last thirty years, one of these technologies, magnetoencephalography (measurement of the magnetic field created by neural activity), has been combined with another tool, electroencephalography, to provide the 'bioelectromagmetic signature' of the activity of the brain. A third technology, based on the diffusion and absorption of infrared light by perfused brain tissues, makes it possible to measure the hemodynamic variations caused by neural activity. Such measurements are essential in evaluating a pathology in a clinical setting, like epilepsy, for example, or in the neurosciences and cognitive sciences, in which the brain functions are studied in particular situations, like during sleep or when the brain is engaged in tasks involving perception or memory, for example. This research program focuses on the digital tools that make it possible to process optical and bioelectomagnetic measurements on a computer, in order to visualize the regions of the cortex involved in the complex and dynamic networks that constitute brain activity. We will also study the intracranial electrophysiological measurements recorded in epileptic patients evaluated within the framework of a surgery, by studying the bursts of rapid oscillations that occur, and seem, some of them at least, to be related to the pathology. To characterize these signals from the point of view of their spectral complexity at the head surface is one of the challenges of this research program, which is aimed at developing new methods of analyzing the 'working human brain'.