Estimation of Epileptic Source Location by Means of the Dipole Tracing Method

偶极子追踪法估计癫痫源位置

基本信息

批准号：
02044054
负责人：
MUSHA Toshimitsu
金额：
$ 3.26万
依托单位：
Tokyo Institute of technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1990
资助国家：
日本
起止时间：
1990 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02044054/
关键词：
Dipole Tracing Dipole EEG Cognition 脳電位 EEG

项目摘要

The Dipole Tracing (abbreviated as DT) system which we have developed in these ten years is aimed at estimating locations, as a function of time, of active neurons in the human brain in terms of the scalp potentials. This method is based on a realistic head model with uniform electric conductivity. Difficulty inherent in this method is in removal of the effect of skull which has electric conductivity as low as 1/80 times that of the brain tissue. A systematic displacement of the estimated current dipoles towards the center of the skull by 30% was observed as a result of the experiment at University Hospital, Uppsala, Sweden, and this number was used mostly successfully. However, when the head is very remote from a sphere, it is difficult to find the center for the correction, and moreover when electric sources in the brain are separated in space we also have a difficulty in the skull correction. We have obtained a new idea for skull correction technique which can be used automatically … More on computer work. The basic idea is the following. The observed scalp potentials generated by an artificial current dipole on the cortical surface at a know position are compared with scalp potentials which would be obtained without the skull. A linear transformation between these should be numerically derived. If algorithm of finding this transformation matrix is found, the correct position of a dipole is automatically obtained. The detail mathematical processes are under investigation. The skull correction in case of two simultaneous dipoles is not clear as yet. The Uppsala group has their own data acquisition system which is compatible to ours and are sending us data magnetic tape routinely for us to make a data base for the skull correction and tracing abnormal electric activity during seizure.Cognition processes of single letters and characters were examined with the DT system. When a single letter was presented on the right visual field, the first dipole appeared in the primary visual cortex and then moved to the left visual association area, left angular gyrus, and to left inferior temporo-occipital cortex. Part of our result agrees with PET data. When, on the other hand, a letter was presented on the left visual field, a dipole in the right visual association area moved to the left hemisphere and followed the same path as described above. Less

我们在这十年中开发的偶极子跟踪（作为DT的缩写）旨在根据头皮电位来估算人脑中活性神经元的位置。该方法基于具有均匀电导率的现实头模型。在这种方法中继承的难度是去除颅骨的作用，后者的电导率低至脑组织的1/80倍。由于在瑞典乌普萨拉大学医院的实验中，观察到了将当前偶极子向颅骨中心估计的偶极子的系统位移，并且大部分都成功地使用了该数字。但是，当头部与球体非常遥远时，很难找到校正中心，而且当大脑中的电源在太空中分开时，我们在颅骨校正中也很难。我们已经获得了用于颅骨校正技术的新想法，该技术可以自动使用……更多关于计算机工作的想法。基本思想是以下内容。将人造电流偶极子在知识位置的皮质表面上产生的观察到的头皮电势与没有头骨的头皮电位进行了比较。这些之间的线性转换应在数值上得出。如果找到找到此转换矩阵的算法，则会自动获得偶极子的正确位置。细节数学过程正在研究中。在两个简单的偶极子的情况下，头骨校正尚不清楚。 Uppsala组具有自己的数据采集系统，该系统与我们的数据兼容，并正常向我们发送数据磁带，以便我们在癫痫发作期间为颅骨校正和追踪异常电动活动提供数据库。单个字母和字符的认知过程与DT系统一起检查。当在右视野上显示一个字母时，第一个偶极子出现在主视觉皮层中，然后移动到左视觉结合区域，左角回和左下颞叶枕皮层。我们的一部分结果与宠物数据一致。另一方面，当左视野上呈现一个字母时，右视觉关联区域的偶极子移动到左半球，并遵循与上述相同的路径。较少的