Hybridised Quantum Optical Sensors for enhanced magnetoencephalography

人脑是我们所知的最复杂的器官和最复杂的计算系统。当大脑由于受伤或紊乱而出现问题时，我们希望快速而准确地处理这些问题。但由于大脑固有的复杂性，要达到诊断和治疗这些疾病所需的成像和刺激的精确度是具有挑战性的。即使在大脑中植入电极，以高分辨率感知和刺激神经元也是足够困难的，但如果你想通过头骨以非侵入性的方式实现这一点，就会增加另一层极端复杂的东西。在这个项目中，我将通过将功能性近红外光谱(FNIRS)与基于光泵磁强计(OPM)的脑磁图(MEG)相结合，实现在获取、获取、查看和诊断用于神经成像的脑信号方面所需的重大变革和技术发展。MEG是一种非侵入性技术，用于成像电生理脑活动。树枝状电流在磁头外部的磁场中产生微小的变化。一组高灵敏度的磁力计检测到这些变化，并重建描述大脑活动每时每刻变化的三维图像。OPM是一种新型的脑磁图量子传感器，因为它们可以测量大脑中的神经元电流等小磁场。FNIRS设备将无害的光发射到组织中，并测量反射光，其中包含有关底层组织中血液流动动力学的信息。由于fNIRS可以测量血管信号，它被证明可以量化内在神经元网络中的功能连接，可与fMRI相媲美。此外，fNIRS还可以为脑健康诊断提供PET代谢生物标记物(血液活性)的等效测量，而不需要将患者暴露在辐射中。最后，fNIRS记录不会干扰OPM-MEG记录(反之亦然)，而且不仅可以同时获取，而且可以在同一传感器中获取。因此，同时记录大脑功能的fNIRS-OPM将首次提供受试者自然环境中大脑健康的所有三个主要生物标志物的衡量标准。具体地说，将测量大脑新陈代谢、内在网络连接和神经振荡。在这个项目中，我将开发混合量子光学传感器(HyQuOS)，这将是第一个在不需要笨重设备的情况下对所有测量使用相同技术的传感器，并将提供两种对比度丰富的信号：神经和血管响应信号，同时创造出一种比单独使用任何一种信号都更丰富的传感器。最后，我的传感器可以被构建成能够抵抗TMS的高磁场脉冲。通过将HyQuOS与TMS相结合，将有可能集中刺激大脑的一个部分，并以极高的精度测量另一部分的反应。这将使我们第一次能够以因果的方式直接评估大脑中的连接性，以测量当不同的大脑网络参与不同的任务时，这种连接性是如何变化的。结合临床结果和神经心理测量数据，我将展示HyQuOS在检测和监测认知和神经连接障碍(如轻度创伤性脑损伤)脑信号方面的潜力。长期目标是开发一种带有多个HyQuOS传感器的全头系统，可以与多个TMS线圈一起使用。除了极大地扩大我们对大脑连接的理解外，一个集成的刺激-测量系统将在考虑到大脑的当前状态的情况下，通过脑刺激为无药物治疗的发展带来突出的新可能性。

The human brain is the most complex organ and the most complex computational system that we know of. When something goes wrong in the brain because of an injury or disorder, we want to quickly and accurately deal with those problems. But because of the inherent complexity of the brain, achieving the level of precision of imaging and stimulation needed to diagnose and treat these disorders is challenging. Sensing and stimulating neurons at a high resolution is hard enough even when electrodes are implanted in the brain, but another layer of extreme complexity is added if you want to achieve this noninvasively, through the skull. In this project I will achieve a significant step-change and technological development required in the accessibility, acquisition, viewing and diagnostic usage of brain signals for neuroimaging by combining functional Near Infrared Spectroscopy (fNIRS) with magnetoencephalography (MEG) based on Optically Pumped Magnetometers (OPM) which I will interfere with Transcranial Magnetic Stimulation (TMS).MEG is a non-invasive technique for imaging electrophysiological brain activity. Dendritic current flow generates small changes in the magnetic field outside the head. An array of highly sensitive magnetometers detects these changes and 3-dimensional images depicting moment-to-moment changes in brain activity are reconstructed. OPMs are a novel type of quantum sensors for MEG as they allow measuring small magnetic fields such as neuronal currents in the brain. fNIRS devices transmit harmless light into tissue and measure the reflected light, which contains information about the dynamics of blood flow in underlying tissue. As fNIRS can measure the vascular signal, it is shown to quantify functional connectivity within the intrinsic neuronal networks, comparable to fMRI. Furthermore, fNIRS can also provide an equivalent measure of the PET metabolism biomarker (blood activity) for brain health diagnosis, without the need to expose the patient to radiation. Finally, fNIRS recordings do not interfere with OPM-MEG recordings (or vice versa) and can not only be acquired simultaneously but within the same sensor. Consequently, a simultaneous fNIRS-OPM recording of brain function will provide, for the first time, a measure of all three primary biomarkers of brain health in a subject's natural environment. Specifically, cerebral metabolism, intrinsic network connectivity, and neural oscillations will be measured. In this project I will develop Hybridised Quantum Optical Sensors (HyQuOS) that will be the first to use the same technology for all measurements without the need for bulky equipment and will provide two contrast-rich signals: those of neural and vascular response, simultaneously, creating a sensor that will be richer than either alone. Finally, my sensor can be built to be resistant to the high magnetic field pulses of TMS. By combining HyQuOS with TMS, it will be possible to focally excite one part of the brain and measure the response in another part with great precision. This will allow us for the first time to directly assess connectivity in the brain in a causal manner, to measure how this connectivity changes when different brain networks are engaged in different tasks. Along with clinically derived outcome and neuro-psychometric data, I will demonstrate the potential of HyQuOS for the detection and monitoring of brain signals for cognitive and neuro-connectivity impairment such as mild Traumatic Brain Injury. The long-term goal is to develop a whole-head system with multiple HyQuOS sensors that can be used with multiple TMS coils. Besides greatly enlarging our understanding of brain connectivity, an integrated stimulus-measurement system will bring outstanding new possibilities in the development of drug-free treatment by brain stimulation taking into account the current state of the brain.