Integrating EEG/MEG and fMRI

我们早期的基础研究表明，认知任务中的脑磁图记录能够以与功能磁共振相当的方式定位大脑活动。具体地说，大脑皮层贝塔频段功率的降低总体上与大胆的激活结果一致。然而，电生理记录，如脑磁图/脑电信号，具有精细的时间动力学，这是其他成像技术所不能实现的。我们还发现，前扣带回皮质的GABA浓度与空间定位的静息MEGβ频带功率相关。我们扩大了匹配良好的受试者的队列，并隔离了特定频段的差异，特别是在高伽马范围(65至115赫兹)。 精神分裂症患者在工作记忆任务中的激活程度，特别是以β去同步化为指标的额叶区域，与健康的兄弟姐妹和健康志愿者相比存在差异。以前我们已经看到，这种激活揭示了与研究得很好的COMT标记的基因型之间的相互作用。当患者、兄弟姐妹和对照组的工作记忆任务表现相匹配时，患者表现出明显的DLPFC激活减少，明显区别于相对于任务负荷的BOLD增加。脑磁图分析分离出一个工作记忆成分，它可能反映了大脑皮质处理的不同方面。我们已经扩展了这些结果，以检查不同组之间高伽马频段的差异。不同频段与血流激活模式的关系揭示了潜在患者差异的神经生理学更具体的靶点。我们现在也在比较服用和停用抗精神病药物的患者的这些差异。看来，药物治疗可能会减弱PFC的差异。我们还扩大了我们的遗传比较，以检查SCN2A的调制，这是一个编码钠通道α-2亚单位的基因。其他研究已经表明，不同群体的认知表现存在差异，脑磁图来源定位显示，不同任务交互作用的DLPFC和DACC存在显著差异。 网络模式和动力学的差异是理解临床组潜在病理的关键。在此之前，巴西特等人。已经表明，患者群体中的功能网络差异可能与认知活动的行为结果有关。我们发现，参与这些记忆任务的大脑区域的时间序列有明显的模式，显示出不同受试者的不同个体差异。我们正在继续利用各种新的方法来检查与认知任务需求有关的信息流。我们以前证明了静息脑磁图记录中存在临界动力学，现在正在将其扩展到与精神分裂症患者进行比较。

Our earlier basic studies have shown that MEG recordings during cognitive tasks have the ability to localize brain activity in comparable fashion to functional MRI. In specific, reduction in power in the beta frequency band at the cortex in general agrees with BOLD activation results. However, electrophysiological recordings such as the MEG/EEG have fine grained time dynamics not possible with other imaging techniques. We have also found that GABA (gamma-aminobutyric acid) concentration in the anterior cingulate cortex correlates with spatially localized resting MEG beta band power. We have expanded the cohort of well-matched subjects and isolated specific frequency band difference especially in the high gamma range (65 to 115 Hz). Differences in the degree of activation especially in frontal regions as indexed by beta desynchronization during a working memory task have been found between patients with schizophrenia compared to well siblings and healthy control volunteers. Previously we have seen that this activation reveals an interaction with genotype for the well-studied COMT marker. With groups of patients, siblings and controls matched for working memory task performance, patients show a distinct reduced DLPFC activation in apparent distinction to an increase in BOLD relative to task load. The MEG analysis isolates a working memory component that may reflect a different aspect of cortical processing. We have extended these results to examine differences in the high gamma band across groups. The relation of the different frequency bands to patterns of blood flow activation have revealed more specific targets for the neurophysiology underlying patient differences. We are now also comparing these differences in patients on and off anti-psychotic medication. It appears that medication may attenuate the PFC differences. We are also extending our genetic comparisons to examine modulation by SCN2A, a gene encoding the alpha-2 subunit of the sodium channel. Other studies have shown variation in cognitive performance across group, with MEG source localization showing significant differences in DLPFC and dACC for genotype by task interactions. Differences in network patterns and dynamics are key to understanding underlying pathology in clinical groups. Previously Bassett et al. have shown that functional network variations in patient groups can be related to behavioral outcomes on cognitive activities. We have found distinct patterns of the temporal sequence of brain regions involved in these memory tasks that show a variety of individual differences across subjects. We are continuing to utilize a variety of new measures to examine the flow of information in relation to cognitive task demand. We previously demonstrated that critical dynamics exist in resting MEG recordings and are now expanding this to compare patients with schizophrenia.