Institut de Neurosciences des Systèmes (INS), Inserm, Aix Marseille Univ, Marseille, France.
Philos Trans A Math Phys Eng Sci. 2019 Sep 9;377(2153):20180132. doi: 10.1098/rsta.2018.0132. Epub 2019 Jul 22.
The timing of activity across brain regions can be described by its phases for oscillatory processes, and is of crucial importance for brain functioning. The structure of the brain constrains its dynamics through the delays due to propagation and the strengths of the white matter tracts. We use self-sustained delay-coupled, non-isochronous, nonlinearly damped and chaotic oscillators to study how spatio-temporal organization of the brain governs phase lags between the coherent activity of its regions. In silico results for the brain network model demonstrate a robust switching from in- to anti-phase synchronization by increasing the frequency, with a consistent lagging of the stronger connected regions. Relative phases are well predicted by an earlier analysis of Kuramoto oscillators, confirming the spatial heterogeneity of time delays as a crucial mechanism in shaping the functional brain architecture. Increased frequency and coupling are also shown to distort the oscillators by decreasing their amplitude, and stronger regions have lower, but more synchronized activity. These results indicate specific features in the phase relationships within the brain that need to hold for a wide range of local oscillatory dynamics, given that the time delays of the connectome are proportional to the lengths of the structural pathways. This article is part of the theme issue 'Nonlinear dynamics of delay systems'.
大脑区域活动的时间可以通过其振荡过程的相位来描述，这对大脑功能至关重要。大脑的结构通过传播延迟和白质束的强度来限制其动态。我们使用自维持的延迟耦合、非等时、非线性阻尼和混沌振荡器来研究大脑的时空组织如何控制其区域相干活动之间的相位滞后。大脑网络模型的计算机模拟结果表明，通过增加频率，从同相到反相同步的稳健切换，连接更强的区域的滞后更加一致。Kuramoto 振荡器的早期分析很好地预测了相对相位，证实了时间延迟的空间异质性是塑造功能大脑结构的关键机制。增加频率和耦合也会通过降低幅度来扭曲振荡器，而较强的区域具有较低但更同步的活动。这些结果表明，在给定连接组的时间延迟与结构通路的长度成正比的情况下，大脑内的相位关系具有特定的特征，需要在广泛的局部振荡动力学范围内保持。本文是主题为“延迟系统的非线性动力学”的一部分。
