Integrating EEG/MEG and fMRI

我们早期的基础研究表明，认知任务期间的MEG记录具有与功能性MRI相当的定位大脑活动的能力。具体来说，皮质β频段的功率降低一般与BOLD激活结果一致。然而，诸如MEG/EEG的电生理记录具有其他成像技术不可能实现的细粒度时间动态。 我们还发现，GABA（γ-氨基丁酸）在前扣带皮层浓度与空间定位静息脑磁图β带功率。我们扩大了匹配良好的受试者队列，并隔离了特定的频带差异，特别是在高伽马范围（65至115 Hz）。 在工作记忆任务中，精神分裂症患者与健康的同胞和健康对照志愿者相比，激活程度的差异，特别是在额叶区域，以β去极化为指标。以前我们已经看到，这种激活揭示了一个相互作用与基因型的充分研究COMT标记。 与组的患者，兄弟姐妹和对照组匹配的工作记忆任务的性能，患者表现出明显的区别，以增加BOLD相对于任务负荷的DLPFC激活明显减少。脑磁图分析分离出一个工作记忆成分，它可能反映了皮层处理的不同方面。我们已经扩展了这些结果，以检查各组之间高伽马波段的差异。不同频带与血流激活模式的关系揭示了患者差异背后的神经生理学的更具体目标。 我们现在也在比较服用和不服用抗精神病药物的患者的这些差异。 药物治疗似乎可以减弱PFC的差异。 我们还扩展了我们的遗传比较，以检查SCN 2A的调节，SCN 2A是一种编码钠通道α-2亚基的基因。其他研究表明，各组的认知表现存在差异，MEG源定位显示基因型与任务相互作用的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中潜在病理学的关键。之前Bassett等人已经表明，患者群体中的功能网络变化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具有不同的模式，这些模式显示出受试者之间的各种个体差异。我们正在继续利用各种新的措施来检查信息流与认知任务的需求。 我们以前证明了临界动力学存在于静息脑磁图记录中，现在正在扩展这一点，以比较精神分裂症患者。

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.