Rutter Lindsay, Carver Frederick W, Holroyd Tom, Nadar Sreenivasan Rajamoni, Mitchell-Francis Judy, Apud Jose, Weinberger Daniel R, Coppola Richard
MEG Core Facility, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
Hum Brain Mapp. 2009 Oct;30(10):3254-64. doi: 10.1002/hbm.20746.
The "default network" represents a baseline condition of brain function and is of interest in schizophrenia research because its component brain regions are believed to be aberrant in the disorder. We hypothesized that magnetoencephalographic (MEG) source localization analysis would reveal abnormal resting activity within particular frequency bands in schizophrenia.
Eyes-closed resting state MEG signals were collected for two comparison groups. Patients with schizophrenia (N = 38) were age-gender matched with healthy control subjects (N = 38), and with a group of unmedicated unaffected siblings of patients with schizophrenia (N = 38). To localize 3D-brain regional differences, synthetic aperture magnetometry was calculated across established frequency bands as follows: delta (0.9-4 Hz), theta (4-8 Hz), alpha (8-14 Hz), beta (14-30 Hz), gamma (30-80 Hz), and super-gamma (80-150 Hz). PRINCIPLE OBSERVATIONS: Patients with schizophrenia showed significantly reduced activation in the gamma frequency band in the posterior region of the medial parietal cortex. As a group, unaffected siblings of schizophrenia patients also showed significantly reduced activation in the gamma bandwidth across similar brain regions. Moreover, using the significant region for the patients and examining the gamma band power gave an odds ratio of 6:1 for reductions of two standard deviations from the mean. This suggests that the measure might be the basis of an intermediate phenotype.
MEG resting state analysis adds to the evidence that schizophrenic patients experience this condition very differently than healthy controls. Whether this baseline difference relates to network abnormalities remains to be seen.
“默认网络”代表大脑功能的一种基线状态，在精神分裂症研究中备受关注，因为人们认为该网络的组成脑区在这种疾病中存在异常。我们假设脑磁图（MEG）源定位分析将揭示精神分裂症患者在特定频段内的静息活动异常。
为两个比较组收集闭眼静息状态下的MEG信号。精神分裂症患者（N = 38）在年龄和性别上与健康对照受试者（N = 38）相匹配，同时与一组未服药的精神分裂症患者的未患病同胞（N = 38）相匹配。为了定位三维脑区差异，在以下既定频段计算合成孔径磁力测量值：δ波（0.9 - 4赫兹）、θ波（4 - 8赫兹）、α波（8 - 14赫兹）、β波（14 - 30赫兹）、γ波（30 - 80赫兹）和超γ波（80 - 150赫兹）。
精神分裂症患者在内侧顶叶皮质后部的γ频段激活显著降低。作为一个群体，精神分裂症患者的未患病同胞在类似脑区的γ频段带宽内激活也显著降低。此外，以患者的显著区域为基础并检查γ频段功率，得出从平均值降低两个标准差的优势比为6:1。这表明该测量指标可能是一种中间表型的基础。
MEG静息状态分析进一步证明，精神分裂症患者体验这种状态的方式与健康对照者有很大不同。这种基线差异是否与网络异常有关还有待观察。
