A Room Temperature Atomic Magnetrode System for Telemetry of Epileptic Seizures

 描述(申请人提供)：脑磁图(MEG)长期以来一直被认为是定位人类癫痫发作的一种非侵入性工具，因为与头皮脑电(EEG)相比，它具有更高的空间分辨率。然而，这一前景一直难以捉摸，这不是因为缺乏敏感度或空间分辨率，而是因为目前的低温(超导)技术的大尺寸和静止不动，阻碍了通常需要进行长期遥测来捕捉这些非常罕见的癫痫样事件。为了克服这一限制，本项目将致力于开发一种实用的非低温(室温)微制造原子磁强计(“磁极”)，该磁极基于Rb蒸气的激光光谱，在尺寸和灵活性上与头皮脑电电极相似。该项目基于我们已发表的初步结果，其中我们使用微电子机械系统(MEMS)技术构建了一个工作的微型磁极，并在动物模型中对其进行了测试，以测量单个癫痫放电的神经元电流和更微妙的自发脑活动，其高信噪比接近于目前的超导传感器。这些测量是朝着高分辨率无创遥测癫痫发作障碍人类事件的目标迈出的有希望的一步，并构成了本提案的基础。该项目的近期目标将是解决在我们目前的原型磁极与可实际应用于癫痫患者术前评估的原型磁极之间的差距所涉及的关键问题。这些问题集中在降低噪音和提高敏感度，最终允许头皮测量发作期和发作间歇期在颞叶浅和深区域的棘波。为此，我们将把我们的磁极开发成降低噪声的梯度计，将我们用于主动消除固定记录轨迹附近的磁场梯度的新方法转化为新型跟踪线圈系统，以消除运动(横卧但不受约束)患者的梯度，并构建用于场映射和有源噪声消除(AIM 1)的多通道磁极原型，优化信号源建模并使用多通道磁极实施“软件屏蔽”(AIM 2)，以及使用磁极遥测对癫痫患者的听觉诱发磁场和癫痫发作进行概念验证测量(AIM 3)。如果成功，该项目的结果将为我们开发高分辨率多通道脑磁图系统的长期目标提供技术基础和理由，该系统用于在无屏蔽或最小屏蔽的环境中对人类癫痫进行移动遥测，以及对其他神经疾病(和正常行为的大脑)进行遥测，在这些环境中，扩展移动神经成像是必不可少的。

 DESCRIPTION (provided by applicant): Magnetoencephalography (MEG) has long held the promise of providing a non-invasive tool for localizing epileptic seizures in humans due to its high spatial resolution compared to the scalp electroencephalogram (EEG). Yet, this promise has been elusive, not due to a lack of sensitivity or spatial resolution, but due to the fact that he large size and immobility of present cryogenic (superconducting) technology prevents long-term telemetry often required to capture these very infrequent epileptiform events. To circumvent this limitation, this project will be devoted to the development of a practical non-cryogenic (room temperature) microfabricated atomic magnetometer ("magnetrode") based on laser spectroscopy of rubidium vapor and similar in size and flexibility to scalp EEG electrodes. The project is based on our published preliminary results in which we used Micro-Electro-Mechanical Systems (MEMS) technology to construct a working miniature magnetrode and tested it in an animal model to measure neuronal currents of single epileptic discharges and more subtle spontaneous brain activity with a high signal-to-noise ratio approaching that of present superconducting sensors. These measurements are a promising step toward the goal of high- resolution noninvasive telemetry of epileptic events in humans with seizure disorders, and form the foundation of the present proposal. The immediate objectives of this project will be to solve key issues involved in bridging the gap between our present prototype magnetrode and one that can be practically applied for presurgical evaluation of epilepsy patients. These issues center on reducing noise and increasing sensitivity to eventually permit scalp measurements of ictal onset and interictal spikes in both superficial and deep temporal lobe regions. To this end, we will develop our magnetrode into a gradiometer to reduce noise, transform our new methods for actively canceling magnetic field gradients near a stationary recording locus into a novel tracking coil system to cancel gradients in moving (recumbent but not restrained) patients and construct a prototype multi-channel magnetrode for field mapping and active noise cancellation (AIM 1), optimize source modeling and implement "software shielding" with the multi-channel magnetrode (AIM 2), and perform proof of concept measurements of auditory evoked fields and seizures using magnetrode telemetry in epilepsy patients (AIM 3). If successful, the results of this project will provide both the technological basis and justification for our longer-range goal f developing a high-resolution multichannel MEG system for mobile telemetry of human epilepsy in an unshielded or minimally shielded environment, as well as telemetry of other neurological disorders (and the normal behaving brain) where extended mobile neuroimaging is essential.