Rhythm-based Brain Information Processing Unit, CBS-TOYOTA Collaboration Center, RIKEN Center for Brain Science, Wako, Saitama, Japan.
Department of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia.
PLoS Comput Biol. 2021 Apr 16;17(4):e1008929. doi: 10.1371/journal.pcbi.1008929. eCollection 2021 Apr.
Metastability in the brain is thought to be a mechanism involved in the dynamic organization of cognitive and behavioral functions across multiple spatiotemporal scales. However, it is not clear how such organization is realized in underlying neural oscillations in a high-dimensional state space. It was shown that macroscopic oscillations often form phase-phase coupling (PPC) and phase-amplitude coupling (PAC), which result in synchronization and amplitude modulation, respectively, even without external stimuli. These oscillations can also make spontaneous transitions across synchronous states at rest. Using resting-state electroencephalographic signals and the autism-spectrum quotient scores acquired from healthy humans, we show experimental evidence that the PAC combined with PPC allows amplitude modulation to be transient, and that the metastable dynamics with this transient modulation is associated with autistic-like traits. In individuals with a longer attention span, such dynamics tended to show fewer transitions between states by forming delta-alpha PAC. We identified these states as two-dimensional metastable states that could share consistent patterns across individuals. Our findings suggest that the human brain dynamically organizes inter-individual differences in a hierarchy of macroscopic oscillations with multiple timescales by utilizing metastability.
大脑中的亚稳性被认为是涉及认知和行为功能在多个时空尺度上动态组织的一种机制。然而，目前尚不清楚这种组织是如何在高维状态空间中的潜在神经振荡中实现的。研究表明，宏观振荡通常形成相位-相位耦合（PPC）和相位-幅度耦合（PAC），分别导致同步和幅度调制，即使没有外部刺激也是如此。这些振荡也可以在静息时自发地跨越同步状态进行转换。使用静息状态脑电图信号和从健康人类获得的自闭症谱系商评分，我们展示了实验证据，表明 PAC 与 PPC 的结合允许幅度调制具有瞬态性，并且具有这种瞬态调制的亚稳动力学与自闭症样特征相关。在注意力持续时间较长的个体中，这种动力学通过形成 delta-alphaPAC 往往会表现出较少的状态间转换。我们将这些状态识别为二维亚稳状态，它们可以在个体之间共享一致的模式。我们的研究结果表明，人类大脑通过利用亚稳性，在具有多个时间尺度的宏观振荡层次上动态组织个体间差异。
