DEVELOPMENT OF LOW FREQUENCY MEG HARDWARE AND SOFTWARE

我们研究的持续目标是开发硬件，软件和技术，以扩大脑磁图（MEG）的实用性，既作为临床诊断工具，也作为神经科学基础研究的模式。 随着我们实验室中现在可用的大型阵列、全头部神经磁力计，并且这种系统变得更加普遍可用，但价格相当高，MEG的附加实用性的证明变得更加重要。 本实验室开发的复杂的数学分析技术，有限差分场映射（FDFM）和二维逆成像（2DII），以及几个商业软件包，将应用于从潜在的癫痫手术患者收集的临床数据，用于术前映射和源定位。 这些技术的结果将系统地比较标准的等效电流偶极子（ECD）的分析，在一些机构进行。 还将使用癫痫手术候选人研究利用颞叶癫痫患者发作后产生的伪DC磁场进行源定位的第二种方法。DC MEG技术将用于偏头痛和中风患者的持续研究。 在下一个资助期间，将使用与从动物模型中的扩散性皮质抑制测量的信号基本相同的MEG信号来研究有先兆的偏头痛和无先兆的偏头痛（经典和普通偏头痛）之间的生理差异和相似性。将开发使用MEG测量确定中风患者康复和恢复的方法。在所有前述研究中，将使用由相同条件下的良好建立的动物模型产生的MEG信号来验证在人类中检测到的MEG信号的性质。 这些研究将在皮质逐渐复杂的三个种属（大鼠、家兔和猪）中进行。将研究使用动态周期分析（DPA）来产生伴随唤醒变化和睡眠的皮层活动变化的整个头部映射。 2DII成像将用于定义与睡眠相关的主动离散和扩展源活动。脑磁图的空间和时间分辨率将被用来研究阅读障碍的主题，并定位异常活动的区域。 将使用一系列视觉/听觉刺激，包括文字、图片和形状识别。 如果在年轻成人阅读障碍者中取得成功，该研究将扩展到儿童和其他学习障碍者。

The ongoing objective of our research has been to develop hardware, software, and techniques to expand the utility of Magnetoencephalography (MEG), both as a clinical diagnostic tool, and as a modality for basic studies in the neurosciences. With a large array, whole head neuromagnetometer now available in our lab, and such systems becoming more generally available, but at quite high prices, the demonstration of added utility for MEG becomes even more significant. Sophisticated mathematical analytical techniques develooped in this lab, finite difference field mapping (FDFM) and two dimensional inverse imaging (2DII), as well as several commercial software packages, will be applied to clinical data gathered from potential epilepsy surgery patients, for presurgical mapping and source localization. The results of these techniques will be systematically compared to the standard equivalent current dipole (ECD) analysis, carried out at a number of institutions. A second method of source location utilizing the pseudo-DC magnetic fields arising post- ictally in temporal lobe epilepsy patients will also be studied using epilepsy surgery candidates. DC MEG techniques will be utilized for a continuing study of migraine and stroke patients. During the next grant period the physiological differences and similarities between migraine with aura and migraine without aura (classic and common migraine) will be studied using MEG signals essentially identical to signals measured from spreading cortical depression in animal models. Methods for using MEG measurements for determining rehabilitation and recovery in stroke patients will be developed. In all of the foregoing studies, the nature of the MEG signals detected in humans will be validated using the MEG signals arising from well-established animal models of the same conditions. These studies will be conducted in three species with progressively more complex cortexes, rat, rabbit, and swine. The use of dynamic period analysis (DPA) to produce whole head mapping of the changes in cortical activity accompanying arousal changes and sleep will be studied. 2DII imaging will be used to define active discrete and extended source activity associated with sleep. The spatial and temporal resolution of MEG will be utilized to study dyslexic subjects, and to localize regions of abnormal activity. A series of visual/auditory stimuli involving word, picture, and shape recognition will be used. If successful with young adult dyslexics, the study will be extended the study to children and individuals with other learning disabilities.