Next generation neuroimaging using optically pumped magnetometers

使用光泵磁力计的下一代神经成像

• 批准号: 2429782
• 金额: --
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2429782
• 关键词: Next; generation; neuroimaging; using; optically

Much of what we understand about the human brain comes from functional neuroimaging - a collection of extremely powerful non-invasive techniques which can measure brain activity in real time, such as functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG). However, perhaps the biggest limitation of these techniques is that they are heavily reliant on subjects lying very still within large and cumbersome scanners. For example, MEG measures magnetic fields outside the head generated by current flow in the brain. In current devices, the requirement for cryogenically cooled magnetic field sensors means that those sensors are fixed in position, and any head movement during scanning degrades the quality of the data. The requirement that subjects remain still limits both the subject cohorts that can be scanned (e.g. it is hard to scan children) and the types of experimental paradigm that can be accessed (e.g. it is challenging to measure brain activity during natural tasks such as learning to play a musical instrument, or whilst a subject is immersed in virtual reality). These limitations are however being lifted by the introduction of quantum technology to functional imaging. New quantum enabled 'wearable' MEG systems are now under development in Nottingham and elsewhere. These systems are built around optically pumped magnetometers - small and lightweight field sensors that can be mounted directly on the head. Flexibility in sensor placement means that systems can be adapted to any head shape or size. Further, if background fields are appropriately nulled, subjects can move freely during data collection. Though still a nascent technology, these new wearable scanners are making significant headway in enabling a new generation of neuroscientific experimentation. However, little is yet known about their fundamental capabilities. In this Ph.D., we will work on the development, characterisation, and application of Nottingham's wearable MEG device, with a view to turning it into a commercial device. At a fundamental level we will work on how to deploy OPM sensors in an optimised array around the scalp to maximise both coverage and spatial resolution. Using techniques including blind source separation we will characterise spatial resolution and its dependence on sensor separation, sensor cross talk (which we will mathematically model), and signal to noise ratio (the latter being improved by reference array measurements). We will work on characterising the bandwidth of the OPM based scanner: Bandwidth is particularly important for clinical studies; here we will look to very high frequency measurements, attempting to measure signals outside what is conventionally thought to be the higher end of the bandwidth of an OPM. Finally, we will develop new experimental paradigms. Specifically, using a three-projector set up and polarised light, we will build a virtual reality CAVE inside Nottingham's newly installed magnetically shielded room. We will then use this to assess how the human brain responds to making decisions in stressful situations.

我们对人类大脑的大部分了解都来自功能性神经成像技术--一系列功能强大的非侵入性技术，可以真实的实时测量大脑活动，如功能性磁共振成像（fMRI）或脑磁图（MEG）。然而，也许这些技术的最大限制是，它们严重依赖于躺在大型和笨重的扫描仪内非常安静的受试者。例如，MEG测量由大脑中的电流流动产生的头部外部的磁场。在当前的设备中，对低温冷却磁场传感器的要求意味着这些传感器被固定在适当的位置，并且在扫描期间的任何头部移动都会降低数据的质量。受试者保持静止的要求限制了可以扫描的受试者群体（例如，难以扫描儿童）和可以访问的实验范例的类型（例如，在自然任务期间测量大脑活动具有挑战性，例如学习演奏乐器，或者当受试者沉浸在虚拟现实中时）。然而，通过将量子技术引入功能成像，这些限制正在被解除。诺丁汉和其他地方正在开发新的量子"可穿戴“MEG系统。这些系统是围绕光泵磁力计构建的--这种小型轻量的磁场传感器可以直接安装在头部。传感器放置的灵活性意味着系统可以适应任何头部形状或尺寸。此外，如果背景字段被适当地置空，则受试者可以在数据收集期间自由移动。虽然仍是一项新兴技术，但这些新的可穿戴扫描仪在实现新一代神经科学实验方面取得了重大进展。然而，人们对它们的基本能力知之甚少。在这个博士学位中，我们将致力于诺丁汉可穿戴脑磁图设备的开发、表征和应用，以期将其转化为商业设备。在基础层面上，我们将研究如何在头皮周围以优化阵列部署OPM传感器，以最大限度地提高覆盖范围和空间分辨率。使用包括盲源分离的技术，我们将研究空间分辨率及其对传感器分离，传感器串扰（我们将数学模型）和信噪比（后者通过参考阵列测量得到改善）的依赖性。我们将致力于表征基于OPM的扫描仪的带宽：带宽对于临床研究尤其重要;在这里，我们将关注非常高的频率测量，试图测量传统上被认为是OPM带宽高端之外的信号。最后，我们将开发新的实验范式。具体来说，使用三个投影仪设置和偏振光，我们将建立一个虚拟现实洞穴内诺丁汉的新安装的磁屏蔽室。然后，我们将利用这一点来评估人类大脑在压力情况下如何做出决策。