George J S, Aine C J, Mosher J C, Schmidt D M, Ranken D M, Schlitt H A, Wood C C, Lewine J D, Sanders J A, Belliveau J W
Biophysics Group, Los Alamos National Laboratory, New Mexico 87545, USA.
J Clin Neurophysiol. 1995 Sep;12(5):406-31. doi: 10.1097/00004691-199509010-00002.
Integrated analyses of human anatomical and functional measurements offer a powerful paradigm for human brain mapping. Magnetoencephalography (MEG) and EEG provide excellent temporal resolution of neural population dynamics as well as capabilities for source localization. Anatomical magnetic resonance imaging (MRI) provides excellent spatial resolution of head and brain anatomy, whereas functional MRI (fMRI) techniques provide an alternative measure of neural activation based on associated hemodynamic changes. These methodologies constrain and complement each other and can thereby improve our interpretation of functional neural organization. We have developed a number of computational tools and techniques for the visualization, comparison, and integrated analysis of multiple neuroimaging techniques. Construction of geometric anatomical models from volumetric MRI data allows improved models of the head volume conductor and can provide powerful constraints for neural electromagnetic source modeling. These approaches, coupled to enhanced algorithmic strategies for the inverse problem, can significantly enhance the accuracy of source-localization procedures. We have begun to apply these techniques for studies of the functional organization of the human visual system. Such studies have demonstrated multiple, functionally distinct visual areas that can be resolved on the basis of their locations, temporal dynamics, and differential sensitivity to stimulus parameters. Our studies have also produced evidence of internal retinotopic organization in both striate and extrastriate visual areas but have disclosed organizational departures from classical models. Comparative studies of MEG and fMRI suggest a reasonable but imperfect correlation between electrophysiological and hemodynamic responses. We have demonstrated a method for the integrated analysis of fMRI and MEG, and we outline strategies for improvement of these methods. By combining multiple measurement techniques, we can exploit the complementary strengths and transcend the limitations of the individual neuro-imaging methods.
对人体解剖学和功能测量进行综合分析，为人类脑图谱绘制提供了一个强大的范例。脑磁图（MEG）和脑电图（EEG）能提供神经群体动力学出色的时间分辨率以及源定位能力。解剖磁共振成像（MRI）能提供头部和脑部解剖结构出色的空间分辨率，而功能磁共振成像（fMRI）技术则基于相关的血液动力学变化提供神经激活的另一种测量方法。这些方法相互制约且相互补充，从而可以改善我们对功能性神经组织的解释。我们已经开发了许多用于多种神经成像技术的可视化、比较和综合分析的计算工具和技术。从容积MRI数据构建几何解剖模型，可以改进头部容积导体模型，并能为神经电磁源建模提供强大的约束条件。这些方法与针对逆问题的增强算法策略相结合，可以显著提高源定位程序的准确性。我们已开始将这些技术应用于人类视觉系统功能组织的研究。此类研究已经证明存在多个功能上不同的视觉区域，这些区域可以根据其位置、时间动态以及对刺激参数的不同敏感性来分辨。我们的研究还提供了纹状和纹外视觉区域内部视网膜拓扑组织的证据，但也揭示了与经典模型的组织差异。MEG和fMRI的比较研究表明，电生理反应和血液动力学反应之间存在合理但并不完美的相关性。我们已经展示了一种用于fMRI和MEG综合分析的方法，并概述了改进这些方法的策略。通过结合多种测量技术，我们可以利用互补优势，超越个别神经成像方法的局限性。
