Non invasive 3-demensional measurement of brain function with developed synthetic aperture magnetometry

等效电流偶极子（ECD）方法通常用于脑磁图分析，将激活的脑区表示为一个或几个偶极子。对大脑活动的全面认识是不够的，因为大脑的功能过程来源于一定体积的皮层内神经元的激活，而ECD只是将激活大脑的重心作为一个代表性的单点表现出来。本文将合成孔径磁强计（SAM）与空间选择性波束形成器相结合，滤除其他区域的背景脑噪声，从任意目标区域获得有意义的信号。神经磁信号以每体素为单位转换为偶极矩单位；这使得人们能够以更高的灵敏度测量大脑一小部分的电流密度（SAM虚拟传感器方法）。随着统计成像技术的进一步应用，统计成像技术可以评估主动状态和控制状态之间所选频段功率的更多差异。具有统计差异的区域可以在单个MRI上以层析方式显示（SAM统计方法）。本研究分析了以下神经功能过程。由于脑磁图具有较好的空间分辨率，并采用了新型的SAM滤波技术，神经任务诱发的神经磁事件相关同步（ERS）或去同步（ERD）的全脑断层扫描得以实现。运动相关的脑活动，半球优势和手优势的影响被揭示。感觉相关的脑活动：同时和多灶脑激活与甚高频振荡被发现。语言相关脑活动：在无发音阅读任务中，感觉语言区和运动语言区均得到了证实。该方法模拟了脑内电极植入，显示了癫痫放电的起源和传播过程。这意味着要消除侵入性监测。少

The equivalent current dipole (ECD) method conventionally used for analysis for magnetoencephalography represent the activated brain area as one or small number of dipoles. It is not enough for comprehensive understanding of the brain activity, since the functional process of the brain is derived from the activation of neurons in a certain volume of cortex and ECD only displays the center of gravity of activated brain as a representative single point. We applied recently developed synthetic aperture magnetometry (SAM) with a spatially-selective beamformer, which filters out the background brain noise from other regions to obtain the meaningful signals from the arbitrary target regions. The neuromagnetic signals are transformed into units of dipole moment on a per voxel basis ; this enables one to measure the current density of the small portion of the brain with an enhanced sensitivity (SAM virtual sensor method). With further application of statistical imaging technique, statistical d … More ifference in the power of selected frequency band can be evaluated between the active and control states. Those areas with statistical difference can be displayed on the individual MRI in a tomographic manner (SAM statistical method). In this study, following neuro-functional processes were analyzed. Owing to the superior spatial resolution of the MEG and to the novel filtering technique of SAM, the tomography of neuromagnetic event related synchronization (ERS) or desynchronization (ERD) evoked by neurological task was demonstrated for the whole brain.1. Motor-related brain activityThe influence of the hemispheric dominance as well as hand dominance wasdisclosed.2. Sensory-related brain activitySimultaneous and multifocal brain activations with very high frequency oscillation were disclosed.3. Language-related brain activityBoth sensory and motor language area were demonstrated with reading without phonation task.4. EpilepsyThe SAM virtual sensor method demonstrated the origin and the propagation process of epileptic discharges as if the intracranial electrodes were implanted. The elimination of invasive monitoring was implied. Less