Improved Spatial Resolution in Magnetoencephalography with an Optically Pumped Magnetometer Array

项目总结/摘要 本项目的目标是优化脑磁图（MEG）的新策略 神经成像，以大大提高分辨率和降低成本。MEG是一种非侵入性的功能性 神经成像方法，以映射大脑活动，这是有用的研究，如功能性大脑映射和 临床应用，例如术前癫痫标测。使用超导的商用MEG系统 量子干涉装置（SQUID）磁传感器使用具有传感器阵列的固定头盔， 设计用于各种头部尺寸。他们给大多数人的次优测量较小 头，尤其是对孩子。因为MEG信号幅度作为与患者的距离的函数而衰减， 神经源，头盔和头部之间几厘米的空间间隙可以使信号衰减十倍。 此外，将传感器放置在头皮上或附近将使得能够检测头皮中的高空间频率变化。 磁场，这将进一步提高定位神经源的空间分辨率。 本项目的重点是使用光泵磁力计（OPMs），以提高脑磁定位 精度OPM将被构造为独立的传感器模块，以实现灵活的传感器布局。很长的- 长期目标是开发一种基于OPM的全头部MEG系统，该系统可以符合任何头部尺寸， 最大的信号。这可以将空间分辨率提高到1毫米，成本低于低温 meg.本项目的目标是开发一个72通道的OPM脑磁图系统， 覆盖范围，并证明在测量邻近神经元源的空间分辨率提高， 人脑该系统将易于重新配置，以将传感器阵列聚焦在感兴趣的区域上。的 中心假设是，带有靠近头部且彼此靠近的传感器的OPM阵列将 将MEG分辨率提高到接近1 mm的水平。目标1是扩展当前的OPM阵列 从20到72个通道，并使阵列易于重新配置。这种新颖的阵列将容纳所有头部 尺寸，特别是那些小的成人和儿童。更大数量的传感器将允许阵列 同时集中在大脑的两个区域目标2是开发针对以下方面的分析技术： 可重构阵列当阵列针对每个新对象重新定位时， 需要精确的磁源定位和外部噪声抑制。此外，源 定位将根据仿真模型进行改进，这些模型将优化阵列定位， 神经元来源的模型。目的3是比较新的OPM脑磁图和传统的脑磁图的源定位精度 阵列和基于SQUID的商业MEG阵列。这些阵列将通过涉及听觉和听觉的任务进行测试。 视觉刺激，以研究由于改变刺激参数而引起的大脑活动的空间变化。改进 信号大小和空间分辨率应该大大提高所有头部大小人的MEG保真度， 包括早产儿，在理解和治疗脑功能障碍方面具有广泛的应用。

PROJECT SUMMARY/ABSTRACT The goal of this project is to optimize a novel strategy for magnetoencephalography (MEG) neuroimaging to substantially improve resolution and reduce cost. MEG is a non-invasive functional neuroimaging method to map brain activity that is useful for both research, e.g. functional brain mapping and clinical applications, e.g. presurgical epilepsy mapping. Commercial MEG systems using superconducting quantum interference device (SQUID) magnetic sensors use fixed helmets with sensor arrays that are designed for a broad range of head sizes. They give suboptimal measurements for most people with smaller heads and especially for children. Because MEG signal amplitude decays as a function of the distance from the neuronal source, a spatial gap of several cm between helmet and head can attenuate the signal by tenfold. Moreover, placing sensors on or near the scalp would enable detection of high spatial frequency variations in the magnetic field, which would further improve spatial resolution in localizing neuronal sources. This project focuses on the use of optically pumped magnetometers (OPMs) to improve MEG localization accuracy. OPMs will be constructed as individual sensor modules that enable flexible sensor layout. The long- term objective is to develop a full-head MEG system based on OPMs that can conform to any head size to give the largest possible signal. This could improve spatial resolution to 1 mm, at a cost that is lower than cryogenic MEG. The objective of this project is to develop a 72-channel OPM MEG system that gives partial head coverage, and to demonstrate improved spatial resolution in measuring neighboring neuronal sources in the human brain. The system will be readily reconfigurable to focus the sensor array on an area of interest. The central hypothesis is that an OPM array with sensors that are close to the head, and close to each other, will substantially increase MEG resolution to a level approaching 1 mm. Aim 1 is to expand the current OPM array from 20 to 72 channels and to make the array easy to reconfigure. This novel array will accommodate all head sizes, particularly those of small adults and children. The larger number of sensors will allow the array to be concentrated over two sections of the brain simultaneously. Aim 2 is to develop analysis techniques specific to the reconfigurable array. When the array is repositioned for each new subject, real-time array calibration is required for accurate magnetic source localization and external noise suppression. In addition, source localization will be improved based on simulation models that will optimize the array positioning and improve models of neuronal sources. Aim 3 is to compare source localization precision between the novel OPM MEG array and a commercial SQUID-based MEG array. The arrays will be tested with tasks involving auditory and visual stimulation, to study spatial variation of brain activity due to changing stimulus parameters. Improved signal size and spatial resolution should substantially improve MEG fidelity for people of all head sizes, including premature infants, with broad applications in understanding and treating brain dysfunction.