Osaka University, Endowed Research Department of Clinical Neuroengineering, Global Center for Medical Engineering and Informatics, Suita, 565-0871, Japan.
Osaka University Graduate School of Medicine, Department of Neurosurgery, Suita, 565-0871, Japan.
Sci Rep. 2017 Oct 27;7(1):14262. doi: 10.1038/s41598-017-14452-3.
High gamma band (>50 Hz) activity is a key oscillatory phenomenon of brain activation. However, there has not been a non-invasive method established to detect language-related high gamma band activity. We used a 160-channel whole-head magnetoencephalography (MEG) system equipped with superconducting quantum interference device (SQUID) gradiometers to non-invasively investigate neuromagnetic activities during silent reading and verb generation tasks in 15 healthy participants. Individual data were divided into alpha (8-13 Hz), beta (13-25 Hz), low gamma (25-50 Hz), and high gamma (50-100 Hz) bands and analysed with the beamformer method. The time window was consecutively moved. Group analysis was performed to delineate common areas of brain activation. In the verb generation task, transient power increases in the high gamma band appeared in the left middle frontal gyrus (MFG) at the 550-750 ms post-stimulus window. We set a virtual sensor on the left MFG for time-frequency analysis, and high gamma event-related synchronization (ERS) induced by a verb generation task was demonstrated at 650 ms. In contrast, ERS in the high gamma band was not detected in the silent reading task. Thus, our study successfully non-invasively measured language-related prefrontal high gamma band activity.
高伽马波段（>50Hz）活动是大脑激活的一个关键振荡现象。然而，目前还没有建立一种非侵入性的方法来检测与语言相关的高伽马波段活动。我们使用配备超导量子干涉装置（SQUID）梯度计的 160 通道全头脑磁图（MEG）系统，非侵入性地研究了 15 名健康参与者在默读和动词生成任务期间的神经磁活动。个体数据被分为阿尔法（8-13Hz）、贝塔（13-25Hz）、低伽马（25-50Hz）和高伽马（50-100Hz）波段，并使用波束形成器方法进行分析。时间窗口连续移动。进行群组分析以描绘大脑激活的共同区域。在动词生成任务中，在刺激后 550-750ms 的时间窗口中，左额中回（MFG）出现高伽马波段的瞬态功率增加。我们在左 MFG 上设置了一个虚拟传感器进行时频分析，并证明了动词生成任务引起的高伽马事件相关同步（ERS）在 650ms 时出现。相比之下，在默读任务中未检测到高伽马波段的 ERS。因此，我们的研究成功地非侵入性地测量了与语言相关的前额叶高伽马波段活动。
