High-sensitivity optical-atomic MEG

 描述(由申请人提供)：在神经学、临床神经科学和认知神经科学中，人们对使用脑磁图(MEG)以毫秒时间分辨率绘制大脑活动图非常感兴趣。大脑中的电流源活动产生的磁场被超导量子干涉装置(SQUID)线圈保持在接近绝对零度的温度下检测到。鱿鱼线圈在Meg(&lt；100赫兹)的频率范围内具有非理想的灵敏度。低温手术需要将鱿鱼线圈放置在头皮上方2-3厘米的距离，降低空间分辨率。鱿鱼脑磁图线圈的建造和维护费用昂贵，这导致部署空间分辨率较差的脑磁图系统，因为在相当远的距离上对磁场进行有限的采样 在头皮上方。由于这些局限性，脑磁图在脑活动定位(称为磁源成像)方面的巨大潜力尚未被认识到，脑磁图在脑功能定位方面的优势仍有待于研究人员或临床医生广泛开发。在这个项目中，我们提出了一种新的方法来测量室温下头皮的磁场，使用原子光学技术来测量磁场，克服了目前脑磁图技术的所有局限性。我们将使用一种独特的光纤Sagnac干涉仪，它最初是为物理应用而开发的，作为磁力计和梯度计的检测方案，这些磁力计和梯度计在室温下工作，可以放置在头皮上。由此产生的Sagnac MEG技术具有更高的灵敏度(在0.01毫微特斯拉的量子噪声限制下)，更好的空间分辨率，并显著低于SQUID MEG的成本。三轴梯度计将记录大脑磁场的所有三个梯度，并将用幻影头和人类受试者的实验进行测试。将开发一种新的时空编码和解码方案，用于从多个Sagnac梯度仪同时记录。将进行模拟、模型实验和人体实验，为未来的全头Sagnac MEG系统的设计提供信息。

 DESCRIPTION (provided by applicant): In Neurology, Clinical Neuroscience, and Cognitive Neuroscience there is considerable interest in mapping brain activity with millisecond temporal resolution using MEG (Magnetoencephalography). Current source activity in the brain generates magnetic fields that are detected by Superconducting Quantum Interference Device (SQUID) coils maintained at near absolute-zero temperature. SQUID coils have non-ideal sensitivity in the frequency range of MEG (< 100 Hz). Cryogenic operation requires placing the SQUID coils at a distance of 2-3 cm above the scalp, reducing spatial resolution. SQUID MEG coils are expensive to construct and maintain, which has led to the deployment of MEG systems with poor spatial resolution due to the limited sampling of the magnetic field at a significant distance above the scalp. The tremendous potential of MEG for localization of brain activity (known as Magnetic Source Imaging), has not been realized due to these limitations and the advantages of MEG over electroencephalography (EEG) for localization of brain function remains to be widely exploited by researchers or clinicians. In this project, we propose a new method to measure the magnetic fields at the scalp at room temperature using an atomic-optical technique to measure magnetic fields that overcomes all of the limitations of current MEG technology. We will use a unique fiber- optic Sagnac interferometer, which was originally developed for physics applications, as the detection scheme for magnetometers and gradiometers that operate at room temperature and can be placed against the scalp. The resulting Sagnac MEG technology has higher sensitivity (at the quantum noise limit of 0.01 femtoTesla), better spatial resolution, and dramatically lower cost than SQUID MEG. Tri-axis gradiometers that record all 3 gradients of the brain's magnetic field will be constructed and tested with phantom heads and experiments in human subjects. A novel spatial-temporal encoding and decoding scheme will be developed for simultaneous recording from multiple Sagnac gradiometers. Simulations, phantom experiments, and human experiments will be carried out to inform the design of future whole-head Sagnac MEG systems.