At present we have about 40 user accounts representing numerous NIMH, NINDS and NIDCD protocols. There is continual interest from additional groups that are working on protocols and planning studies. ? ? The MEG Core staff has been working interactively with these users in terms of study design, task programming development, acquisition protocols, and signal processing and data analysis. Procedures have been setup for data security, transfer and storage. A substantial Policy and Procedures Manual has been established. We have also worked with the Scientific and Statistical Computing Core to enable transfer of CTF MEG files to AFNI and developed tools for group statistical analysis. ? ? Technical and scientific results continue to be excellent. Signal analysis development includes event-related SAM (synthetic aperture magnetometry) and 275 channel ICA (independent component analysis). Development of time-frequency analysis methods has included Stockwell and wavelet transforms as well as multi-taper techniques. Of particular interest is coherence analysis of virtual channels as a method to investigate interacting brain regions. Staff are working with other MEG groups to integrate several signal processing packages including FieldTrip, NUTMEG and BrainStorm. The goal is to have a unified tool package with a user-friendly interface available to the user community. The SAM software has been successfully run on the Biowulf Cluster allowing for tremendous increase in computing power. A subject eye movement system has been integrated with task presentation software allowing for interactive monitoring of eye position during visual stimulation. ? ? Scientific results follow up from initial successes of localization of amygdala activation with an emotional face task, and a visual system modulation study (Jeff Duyn reports that the MEG visually activated signal has 10 times the SNR compared to BOLD). For a working memory task MEG activation patterns for beta band have shown exceptional agreement with BOLD results in the same subject group. The user community has been very productive? ? Qian Lou and James Blair in a study examining the neural dynamics of facial threat processing have been able to utilize the fine temporal resolution of MEG to learn that there are brian related responses in the amygdale even earlier than in the visual cortex. This supports the suggestion of quick processing route in the brain specific to fear expressions. Understanding these brain mechanisms will be important to further study in mood and affective disorders.? ? Brian Cornwell, Christion Grillion and colleagues have examined how individuals because sensitized to novel stimuli when there are environmental changes that cause anxiety. Using MEG they were able to outline the pathways where brain responses were enhanced to sounds when under threat compared to no threat. These areas included amygdale and insula. Knowledge of these pathways and how they become sensitized may be important for understanding sensitization in disorders such as PTSD.? ? Garolera, Goldberg and colleagues have also examined amygdale activity with MEG; in this case, during a linguistic affective priming task using positive and negative words. A time dependant increase in amygdale activity was seen in response to negative words. They will follow up to explore mechanisms implicated in emotional processing.? 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. To this end Bassett, Meyer-Lindenberg and co-workers used the spatial and temporal ability of MEG to study how the brain changes configuration during a motor task compared to when at rest. They found that functional networks were characterized by small-world properties indicating a mix or both local connections and long range connections. These type of investigations may aid in understanding how brain networks change in dysfunctional states.? ? On going studies include examining hippocampal function in patients with major depression as well as other brain changes when treated with ketamine. These studies are of particular interest to possibly elucidate the mechanism of the anti-depressant action of ketamine infusion. Recent results have shown that increased anterior cingulate activity may be a biomarker that predicts the rapid antidepressant response to ketamine. Rich, Leibenluft and Pine are using MEG to study the neural mechanisms of behavioral inhibition. .
