Integrating EEG/MEG and fMRI: 99-M-0172

脑磁图数据记录和信号处理方法的发展已经非常成功。对工作记忆任务和听觉处理任务的研究已经显示了定位大脑激活和解决阶段性与紧张性活动问题的能力。我们正在调查表型的措施，将适用于许多相关的研究，特别是同胞项目。 认知激活过程中的脑磁图记录显示出与功能磁共振成像非常相似的定位能力。特别是皮质水平的β去磷酸化与BOLD激活结果一致。然而，MEG/EEG允许使用其他成像技术不可能的时间信息。跨大脑区域的相位关系已经使用先进的信号处理技术得到了证明。我们的研究结果表明，大脑结构和功能的措施是找到易感基因的有力工具。进一步的研究已经证明了定位信号在更深的结构，如杏仁核的能力，并调查视觉意识的伽马波段信号的关系。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。我们期望进一步的研究将揭示更多的γ功率和GABA系统之间的关系。 在工作记忆任务中，精神分裂症患者与健康的同胞和正常对照志愿者相比，其激活程度不同，特别是在额叶区域，这是由β去激活所指示的。对这种激活的进一步研究揭示了与已充分研究的COMT标记的基因型的相互作用。我们发现，在预期即将到来的任务需求时，前额叶皮层的活动会发生调制。我们已经将该分析扩展到一组匹配良好的患者、兄弟姐妹和对照组。当工作记忆任务完成受到控制时，患者表现出明显的DLPFC激活减少，与任务负荷相关的BOLD增加明显不同。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。 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。Bassett等人已经表明，患者群体中的功能网络差异可以被证明并与认知活动的行为结果相关。Rutter等人已经表明，即使在休息时，与正常受试者相比，精神分裂症患者的伽马功率也会降低。这些发现是否与状态或特征差异有关以及是否存在遗传关联还有待观察。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。最近的工作与人脸识别任务显示了一个独特的网络区域，表明振荡活动的交叉耦合，可能会导致更好地了解区域的相互作用。 最近的工作试图研究是否可以看到功能性脑网络的重组，以应对认知补救策略。一项对患者和健康对照者在听觉任务训练前后记录的MEG的研究解决了这个问题。我们能够显示出与行为表现改善相关的大脑活动的力量和连贯性的显着变化。这可以形成生物标志物的基础，该生物标志物将允许跟踪针对神经精神障碍中特定认知缺陷的补救策略的结果。

Development of MEG data recording and signal processing methods has been very successful. Studies of working memory tasks and auditory processing tasks have shown the ability to localize brain activation and to address issues of phasic versus tonic activity. We are investigating phenotype measures that will be applicable in many related studies and specifically the sibling project. MEG recording during cognitive activation has shown the ability to localize in very comparable fashion to fMRI. Specifically beta desynchronization at the cortical level has been found to agree with BOLD activation results. However, the MEG/EEG allows for temporal information not possible with other imaging techniques. Phasic relationships across brain areas have been demonstrated using advanced signal processing techniques. Our results show that measures of brain structure and function represent powerful tools to find susceptibility genes. Further studies have demonstrated the ability to localize signals in deeper structures such as the amygdala and to investigate the relation of visual awareness to gamma band signals. 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 expect that further investigation will reveal addtional relationships between gamma power and GABA systems. Diffrerences 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 normal control volunteers. Further investigation of this activation has revealed an interaction with genotype for the well studied COMT marker. We have found there is a modulation of prefrontal cortex activity that occurs in anticipation of the upcoming task demands. We have extended this analysis to a well matched set of patients, siblings and controls. When working memory task perfomance is controlled patients show a distinct reduced DLPFC activation in apparent distinction to increased BOLD relative to task load. The MEG analysis isolates a working memory component that may reflect a different aspect of cortical processing. Differences in network patterns and dynamics are key to understanding underlying pathology in clinical groups. Bassett et al have shown that functional network differences in patient groups can be demonstrated and related to behavioral outcomes on cognitive activities. Rutter et al have shown that even at rest patients with schizophrenia have gamma power reduction compared to normal subjects. It remains to be seen whether these finding relate to state or trait differences and if there are genetic associations. 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. Recent work with face recognition tasks has shown a distinct network of regions that indicates a cross coupling of oscillatory activity that may lead to better understanding of regional interactions. Recent work has sought to examine whether reorganization of functional brain networks can be seen in response to cognitive remediation strategies. A study of MEG recorded before and after auditory task training in both patients and healthy controls addressed this question. We were able to show significant changes in power and coherence in brain activity that were asociated with improved behavioral performance. This could form the basis of a biomarker that would allow tracking the outcome of remediation strategies targeting specific cognitive deficits in neuropsychiatric disorders.