Liu Hesheng, Tanaka Naoaki, Stufflebeam Steven, Ahlfors Seppo, Hämäläinen Matti
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, MA, USA.
J Vis Exp. 2010 Jun 14(40):1668. doi: 10.3791/1668.
We use magnetoencephalography (MEG) and electroencephalography (EEG) to locate and determine the temporal evolution in brain areas involved in the processing of simple sensory stimuli. We will use somatosensory stimuli to locate the hand somatosensory areas, auditory stimuli to locate the auditory cortices, visual stimuli in four quadrants of the visual field to locate the early visual areas. These type of experiments are used for functional mapping in epileptic and brain tumor patients to locate eloquent cortices. In basic neuroscience similar experimental protocols are used to study the orchestration of cortical activity. The acquisition protocol includes quality assurance procedures, subject preparation for the combined MEG/EEG study, and acquisition of evoked-response data with somatosensory, auditory, and visual stimuli. We also demonstrate analysis of the data using the equivalent current dipole model and cortically-constrained minimum-norm estimates. Anatomical MRI data are employed in the analysis for visualization and for deriving boundaries of tissue boundaries for forward modeling and cortical location and orientation constraints for the minimum-norm estimates.
我们使用脑磁图（MEG）和脑电图（EEG）来定位并确定参与简单感觉刺激处理的脑区的时间演变。我们将使用体感刺激来定位手部体感区，听觉刺激来定位听觉皮层，在视野的四个象限中使用视觉刺激来定位早期视觉区。这类实验用于癫痫和脑肿瘤患者的功能图谱绘制，以定位明确的皮层。在基础神经科学中，类似的实验方案用于研究皮层活动的协调。采集方案包括质量保证程序、为联合MEG/EEG研究进行的受试者准备，以及通过体感、听觉和视觉刺激采集诱发反应数据。我们还展示了使用等效电流偶极子模型和皮层约束最小范数估计对数据进行的分析。解剖学MRI数据用于分析中的可视化，以及推导用于正向建模的组织边界和用于最小范数估计的皮层位置及方向约束。
