NIMH MEG Core Facility

MEG核心员工与NIMH、NINDS、NIDCD和NICHD的一大批PI互动工作，进行研究设计、任务开发、采集方案、信号处理和数据分析。通过将主数据档案移至Helix维护的NIMH数据存储，改进了数据安全、传输和存储程序。与科学和统计计算核心合作，以便能够将CTF MEG文件传输到非洲非政府组织，并开发了群体统计分析工具，以前已扩展到包括额外的维度格式，以促进主题群体之间基于时间的联系。这一范围已经扩大，可以跨受试者和群体进行时间维度比较。现在可以使用基于解剖图谱的对象对齐来分析比较。 信号分析在与事件有关的SAM(合成孔径磁学)和275通道ICA(独立分量分析)方面继续发展。时频分析方法的发展包括斯托克韦尔变换和小波变换以及多锥化技术。若干用户群体正在使用扩展到包括用于探索大脑网络的符号熵测量和转移熵互信息技术的分析包，并且现在正将其应用于ECOG数据(这些是直接的皮层记录)。使用SAM波束形成器方法分析Tacs(经颅交流电刺激)和tdcs(经颅直流电刺激)期间和之后的脑磁图信号的能力使人们能够探索对大脑节律和记忆的影响，科恩博士的团队目前正在进行几项研究。 将替换外部电子设备的升级包的早期测试版本已经在所有渠道进行了测试和正常运行。去年，最终版本计划安装，计划在20176秋季全面安装。先前安装和测试的新的眼动监测系统继续促进认知激活范例。电力系统检修后，系统可靠性有了很大提高。一些用户对使用精心控制的颜色视觉刺激进行研究感兴趣。一个新的高质量视觉刺激系统正在安装中。 康威尔和他的同事的早期工作表明，使用脑磁图波束形成技术，脑磁图可以可靠地区分杏仁核和海马区的信号。持续的研究表明，在接受氯胺酮治疗时，患有严重抑郁症和其他脑部变化的患者的海马体功能会受到损害。进一步的研究表明，海马区的快速伽马活动与空间学习相关。这些研究对可能阐明氯胺酮输注的抗抑郁作用的机制特别有意义。先前的研究结果表明，在工作记忆任务中，前扣带回活动的增加和功能连接的增加都可以预测氯胺酮的抗抑郁反应。Zarate和他的同事利用脑磁图表明，突触增强对于治疗难治性重度抑郁症的抗抑郁作用至关重要。在此之前，Nugent等人。显示了脑磁图休息数据的组间差异，这些数据突出了严重抑郁障碍的功能障碍。现在已经扩展到探索氯胺酮给药后的网络变化。SDR Nugent继续了这项工作，并开发了新的分析方法(多波段ICA)，以突出治疗组和临床组中大脑网络的变化。研究人员继续探索任务组和患者组中的高伽马频段活动。与特定钠通道基因的相互作用发现，认知差异可能与伽马波段活动有关。 研究大脑如何将自己组织成功能网络，是理解正常人类认知以及精神疾病中大脑何时变得混乱的关键。此前，巴西特和他的同事利用脑磁图的空间和时间能力发现，功能性网络的特征是小世界属性，表明既有本地连接，也有远程连接。我们还发现了患者群体中休息网络模式的差异，现在已经使用图论方法来检查功能网络。功能连通性度量在视听任务中进行了研究，表明跨大脑区域的交流有几种形式，没有一种衡量标准足以捕捉信息流的丰富性。Grillon和Balderston的新研究显示了焦虑操控过程中连接性的变化。 由Peter Basser的团队开发的将脑磁图动力学与一种新的扩散张量成像(DTI)测量方法相关联的拟议项目已得到资助，协议规划正在进行中。 在科波拉博士和纽金特博士的共同主持下，组织了为期两天的脑磁图讲习班，将北美脑磁图研究界聚集在一起。出席人数非常多，社会人士认为这样的会议早就应该举行了。几个小组讨论了MEG神经科学研究的增值方面，以及如何推进支持性基础设施。将举行后续会议，以建立各实验室之间的协作和协同作用。

The MEG Core staff works interactively with a large group of PIs in NIMH, NINDS, and NIDCD, and NICHD for study design, task development, acquisition protocols, signal processing and data analysis. Procedures for data security, transfer and storage have been improved by moving the main data archive to the Helix maintained NIMH data store. Work with the Scientific and Statistical Computing Core to enable transfer of CTF MEG files to AFNI and developed tools for group statistical analysis was previously extended to include an extra-dimensional format to facilitate time-based connectivity across subject groups. This has been expanded to allow time-dimension comparison across subjects and groups. The comparisons can now be analyzed using anatomic atlas based alignment across subject. Signal analysis development has continued on event-related SAM (synthetic aperture magnetometry) and 275-channel ICA (independent component analysis). Development of time-frequency analysis methods has includedincludes Stockwell and wavelet transforms as well as multi-taper techniques. The analysis packages extended to include symbolic entropy measures and transfer entropy mutual information techniques to explore brain networks are in use by a number of user groups and are now being applied to eCOG data (these are direct cortical recordings). The ability to use SAM beamformer methods to analyze MEG signals during and after tACS (transcranial alternating current stimulation) as well as tDCS (transcranial direct current stimulation) has allowed exploration of effects on brain rhythms and memory and several studies are now underway by Dr. Cohen's group. An early test version of the upgraded package that will replace the external electronics has beenwas tested and performed properly across all channels.last year and the final version is now scheduled for installation Full installation is planned for fall 20176. The new eye-movement monitoring system previously installed and tested continues to contribute to cognitive activation paradigms. System reliability has been substantially improved after power system repairs. Several users are interested in pursuing studies with carefully controlled color visual stimuli. A new high quality visual stimulation system is being installed. Early work by Cornwell and colleagues demonstrated that MEG can reliably discriminate amygdala and hippocampal signals using MEG beamforming techniques. Continuing studies have shown that hippocampal function is impaired in patients with major depression as well as other brain changes when treated with ketamine. Further studies have shown that fast gamma activity in the hippocampus correlates with spatial learning. These studies are of particular interest to possibly elucidate the mechanism of the anti-depressant action of ketamine infusion. Previous results have shown that both increased anterior cingulate activity and functional connectivity during a working memory task can predict the antidepressant response of ketamine. Zarate and colleagues have utilized MEG to show that synaptic potentiation is critical for the antidepressant action in treatment resistant major depression. Previously Nugent et al. have shown group differences in MEG resting data that highlight dysfunction in major depressive disorder. This has now been extended to explore the network changes with ketamine administration. SDr Nugent has continued this work and has developed new analysis methods (multiband ICA) that high light the brain network changes across treatment and clinical groups.tudies continue to explore high gamma band activity across task and patient groups. Interaction with specific sodium channel genes finds that the cognitive differences may be related to gamma band activity. Studying how the brain organizes itself into functional networks is key to understanding normal human cognition as well as when it becomes disordered in mental illness. Previously, Bassett and co-workers using the spatial and temporal ability of MEG found that functional networks were characterized by small-world properties indicating a mix of both local connections and long range connections. We have also found differences in resting network patterns in patient groups, and have now used graph theoretical methods to examine functional networks. Functional connectivity metrics have been studied in an audio-visual task demonstrating that the communication across brain regions takes on several forms and that no one measure will suffice to capture the richness of information flow. New work by Grillon and Balderston has shown connectivity changes during anxiety manipulation. The proposed project to relate MEG dynamics to a new Diffusion Tensor Imaging (DTI) measure for determining latency across brain regions developed by Peter Basser's group was funded and protocol planning is underway. With Drs. Coppola and Nugent as co-chairs a two-day MEG Workshop was organized to bring together the North American MEG research community. Attendance was very strong and the community felt that such a meeting was long overdue. Several panels addressed the value-added aspect of MEG neuroscience research and how a supportive infrastructure can be advanced. A follow-on meeting will be held to build collaboration and synergy across laboratories.