Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, University of Bern, Switzerland.
Clin Neurophysiol. 2012 Aug;123(8):1536-48. doi: 10.1016/j.clinph.2011.12.019. Epub 2012 Feb 2.
Gamma zero-lag phase synchronization has been measured in the animal brain during visual binding. Human scalp EEG studies used a phase locking factor (trial-to-trial phase-shift consistency) or gamma amplitude to measure binding but did not analyze common-phase signals so far. This study introduces a method to identify networks oscillating with near zero-lag phase synchronization in human subjects.
We presented unpredictably moving face parts (NOFACE) which - during some periods - produced a complete schematic face (FACE). The amount of zero-lag phase synchronization was measured using global field synchronization (GFS). GFS provides global information on the amount of instantaneous coincidences in specific frequencies throughout the brain.
Gamma GFS was increased during the FACE condition. To localize the underlying areas, we correlated gamma GFS with simultaneously recorded BOLD responses. Positive correlates comprised the bilateral middle fusiform gyrus and the left precuneus.
These areas may form a network of areas transiently synchronized during face integration, including face-specific as well as binding-specific regions and regions for visual processing in general.
Thus, the amount of zero-lag phase synchronization between remote regions of the human visual system can be measured with simultaneously acquired EEG/fMRI.
在视觉绑定过程中，已经在动物大脑中测量到了伽马零滞后相位同步。人类头皮 EEG 研究使用相位锁定因子（逐次试验相位偏移一致性）或伽马幅度来测量绑定，但迄今为止尚未分析共同相位信号。本研究介绍了一种在人类受试者中识别具有近零滞后相位同步的网络的方法。
我们呈现了不可预测移动的面部部位（NOFACE），这些部位 - 在某些时期 - 产生了完整的示意性面部（FACE）。使用全局场同步（GFS）测量零滞后相位同步的量。GFS 提供了整个大脑中特定频率的即时一致性数量的全局信息。
在 FACE 条件下，伽马 GFS 增加。为了定位潜在的区域，我们将伽马 GFS 与同时记录的 BOLD 反应相关联。正相关包括双侧中梭状回和左侧楔前叶。
这些区域可能形成一个在面部整合过程中暂时同步的区域网络，包括特定于面部的以及特定于绑定的区域，以及一般的视觉处理区域。
因此，具有同时获取的 EEG/fMRI 可以测量人类视觉系统远程区域之间的零滞后相位同步量。
