Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Suita 565-0871, Japan.
Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.
eNeuro. 2020 Apr 24;7(2). doi: 10.1523/ENEURO.0224-19.2020. Print 2020 Mar/Apr.
Neural oscillations at ∼10 Hz, called alpha oscillations, are one of the most prominent components of neural oscillations in the human brain. In recent years, characteristics (power/frequency/phase) of occipital alpha oscillations have been correlated with various perceptual phenomena. However, the relationship between inter-individual differences in alpha oscillatory characteristics and the properties of the underlying brain structures, such as white matter pathways, is unclear. A possibility is that intrinsic occipital alpha oscillations are mediated by thalamocortical interaction; we hypothesized that the most promising candidate for characterizing the intrinsic alpha oscillation is optic radiation (OR), which is the geniculo-cortical pathway carrying signals between the lateral geniculate nucleus (LGN) and primary visual cortex (V1). We used resting-state magnetoencephalography (MEG) and diffusion-weighted/quantitative magnetic resonance imaging (MRI) (dMRI/qMRI) to correlate the frequency and power of occipital alpha oscillations with the tissue properties of the OR by focusing on the different characteristics across individuals. We found that the peak alpha frequency (PAF) negatively correlated with intracellular volume fraction (ICVF), reflecting diffusion properties in intracellular (axonal) space, whereas the peak alpha power was not correlated with any tissue properties measurements. No significant correlation was found between OR and beta frequency/amplitude or between other white matter tract connecting parietal and inferotemporal cortex and alpha frequency/amplitude. These results support the hypothesis that an interaction between thalamic nuclei and early visual areas is essential for the occipital alpha oscillatory rhythm.
约 10 Hz 的神经振荡，称为阿尔法振荡，是人类大脑中神经振荡最显著的组成部分之一。近年来，枕部阿尔法振荡的特征（功率/频率/相位）与各种感知现象相关。然而，个体间阿尔法振荡特征的差异与潜在脑结构（如白质通路）之间的关系尚不清楚。一种可能性是，内在的枕部阿尔法振荡是由丘脑皮质相互作用介导的；我们假设，表征内在阿尔法振荡的最有前途的候选者是视辐射（OR），它是携带从外侧膝状体核（LGN）到初级视觉皮层（V1）之间信号的视放射通路。我们使用静息状态磁共振脑磁图（MEG）和弥散加权/定量磁共振成像（dMRI/qMRI），通过关注个体间的不同特征，将枕部阿尔法振荡的频率和功率与 OR 的组织特性相关联。我们发现，阿尔法波峰值频率（PAF）与细胞内体积分数（ICVF）呈负相关，反映了细胞内（轴突）空间的扩散特性，而阿尔法波峰值功率与任何组织特性测量均不相关。OR 与β频率/幅度之间，以及与连接顶叶和下颞叶皮质的其他白质束与阿尔法频率/幅度之间均未发现显著相关性。这些结果支持了这样一种假设，即丘脑核与早期视觉区域之间的相互作用对于枕部阿尔法振荡节律是必不可少的。
