A Cryogen-Free, Low-Cost Atomic Magnetometer Array for Magnetoencephalography

用于脑磁图的无制冷剂、低成本原子磁力计阵列

• 批准号: 8666751
• 负责人: Peter D. D. Schwindt
• 金额: $ 78.91万
• 依托单位: SANDIA CORP-SANDIA NATIONAL LABORATORIES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8666751
• 关键词: Accounting; Acoustic Nerve; Algorithms; Area; Auditory; Brain; Cells; Child; Clinical; Collaborations; Comparative Study; Computer software; Cost Savings; Coupled; Dementia; Devices; Electroencephalography; Elements; Epilepsy; Evaluation; Finland; Freedom; Frequencies; Functional Magnetic Resonance Imaging; Geometry; Glass; Goals; Head; Helium; Helmet; Human; Image; Individual; Lasers; Lead; Left; Liquid substance; Location; Magnetism; Magnetoencephalography; Measurement; Measures; Mental Depression; Mental disorders; Metals; Mind-Body Method; Modeling; Modification; Neurons; Noise; Performance; Persons; Positioning Attribute; Radial; Research; Research Infrastructure; Resolution; Schizophrenia; Signal Transduction; Site; Source; Subject Headings; Surface; System; Techniques; Temperature; Validation; Work; auditory stimulus; base; cost; cryogenics; design; human subject; improved; instrument; magnetic field; median nerve; meter; millisecond; nervous system disorder; neural circuit; neuroimaging; optical fiber; programs; prototype; quantum; relating to nervous system; response; sensor; simulation; somatosensory; success; superconducting quantum interference device; tool

DESCRIPTION (provided by applicant): Functional neuroimaging has led to important advances in understanding neural circuits and has emerged as an important technique in the study of psychiatric and neurological disorders such as schizophrenia, dementia, depression, and epilepsy, where anatomical imaging is negative or shows only nonspecific findings. Magnetoencephalography (MEG) is the only noninvasive functional neuroimaging technique able to directly measure neural activity with sub-centimeter spatial and millisecond temporal resolution, but its potential as a research and clinical tool has yet to be realized on a large scae due to its high acquisition and operating costs. A large portion of the cost results from the use o superconducting quantum interference device (SQUID) magnetic sensors that must be cooled with liquid helium. The cryogenic infrastructure results in a bulky MEG system that requires installation of a large magnetically shielded room to achieve acceptably low background levels and that has a fixed sensor array geometry that cannot be adjusted for head size. The goal of the proposed work is to develop a small, low-cost MEG system using an array of atomic magnetometers (AMs) as replacements for SQUIDs. AMs can achieve sensitivities comparable to SQUIDs but do not require cryogenic cooling. AMs detect magnetic fields by measuring, via laser interrogation, the interaction between a magnetic field and atoms contained within a glass cell. Recently, we developed a compact optical fiber-coupled AM and used it to detect MEG signals from human subjects. Based on these preliminary studies, we propose to develop a 36-channel array of AMs with partial-head coverage (roughly 12 cm X 12 cm) that is able detect and localize neuronal activity. In Specific Aim #1, we will design critical components of the proposed AM MEG system, including the individual AMs that serve as array elements and a person-sized magnetic shield to contain the AM-array and the human subject. Commercially available magnetic source localization software will be adapted to our array geometry. One AM will be constructed and its performance will be verified at go/no-go specifications of >100 Hz bandwidth and 20 fT/Hz1/2sensitivity. In Specific Aim #2, the AM MEG system will be constructed and its source localization accuracy will be determined by detecting an MEG phantom with the AM array geometry reconfigured to mimic a variety of head sizes. Human studies will commence only after demonstrating sub-centimeter spatial resolution. In Specific Aim #3, the AM system will be compared to a commercial SQUID MEG system by measuring the evoked response in human subjects from median nerve and auditory stimuli with both systems. A successful comparison will identify a neural source in terms of strength and location to within one standard deviation error between the two systems. The results of the proposed work are expected to clear the path for developing a full-head- coverage low-cost AM MEG system that can be adapted to accommodate a wide variety of head sizes.

描述（由申请人提供）：功能性神经成像在理解神经回路方面取得了重要进展，并已成为精神病学和神经疾病（如精神分裂症、痴呆、抑郁症和癫痫）研究中的重要技术，其中解剖成像为阴性或仅显示非特异性发现。脑磁图（MEG）是唯一一种能够以亚厘米空间和毫秒时间分辨率直接测量神经活动的非侵入性功能神经成像技术，但由于其高昂的采集和操作成本，其作为研究和临床工具的潜力尚未在大范围内实现。很大一部分成本来自使用超导量子干涉装置（SQUID）磁传感器，必须用液氦冷却。低温基础设施导致MEG系统体积庞大，需要安装一个大的磁屏蔽室以达到可接受的低背景水平，并且具有固定的传感器阵列几何形状，无法根据头部大小进行调整。这项工作的目标是开发一种小型、低成本的磁脑动图系统，使用一组原子磁强计（AMs）作为squid的替代品。AMs可以达到与squid相当的灵敏度，但不需要低温冷却。AMs通过激光探测，测量玻璃细胞内的磁场和原子之间的相互作用，从而探测磁场。最近，我们开发了一种紧凑的光纤耦合AM，并将其用于检测人体受试者的MEG信号。基于这些初步研究，我们建议开发一种具有部分头部覆盖（大约12厘米X 12厘米）的36通道am阵列，能够检测和定位神经元活动。在具体目标#1中，我们将设计提议的AM MEG系统的关键组件，包括作为阵列元素的单个AM和一个人体大小的磁屏蔽，以包含AM阵列和人体受试者。市售磁源定位软件将适应我们的阵列几何形状。将构建一个AM，其性能将在>100 Hz带宽和20 fT/ hz1 /2灵敏度的go/no-go规格下进行验证。在Specific Aim #2中，将构建AM MEG系统，并通过检测具有重新配置以模拟各种头部尺寸的AM阵列几何形状的MEG幽灵来确定其源定位精度。只有在展示了亚厘米的空间分辨率后，才能开始人体研究。在具体目标#3中，AM系统将通过测量人类受试者中正中神经和听觉刺激的诱发反应，与商用SQUID MEG系统进行比较。成功的比较将在两个系统之间的一个标准偏差误差范围内确定神经源的强度和位置。拟议工作的结果有望为开发全头部覆盖的低成本AM MEG系统扫清道路，该系统可以适应各种头部尺寸。