Values of model parameters.

Stimulation to local areas remarkably affects brain activity patterns, which can be exploited to investigate neural bases of cognitive function and modify pathological brain statuses. There has been growing interest in exploring the fundamental action mechanisms of local stimulation. Nevertheless, how noise amplitude, an essential element in neural dynamics, influences stimulation-induced brain states remains unknown. Here, we systematically examine the effects of local stimulation by using a large-scale biophysical model under different combinations of noise amplitudes and stimulation sites. We demonstrate that noise amplitude nonlinearly and heterogeneously tunes the stimulation effects from both regional and network perspectives. Furthermore, by incorporating the role of the anatomical network, we show that the peak frequencies of unstimulated areas at different stimulation sites averaged across noise amplitudes are highly positively related to structural connectivity. Crucially, the association between the overall changes in functional connectivity as well as the alterations in the constraints imposed by structural connectivity with the structural degree of stimulation sites is nonmonotonically influenced by the noise amplitude, with the association increasing in specific noise amplitude ranges. Moreover, the impacts of local stimulation of cognitive systems depend on the complex interplay between the noise amplitude and average structural degree. Overall, this work provides theoretical insights into how noise amplitude and network structure jointly modulate brain dynamics during stimulation and introduces possibilities for better predicting and controlling stimulation outcomes.

局部区域刺激对大脑活动模式的影响显著，此效应可被利用以探究认知功能的神经基础并调整病态脑状态。对探究局部刺激的基本作用机制的兴趣日益浓厚。然而，噪声幅度——作为神经动力学中一个关键要素——如何影响由刺激引起的脑状态仍是一个未解之谜。在本研究中，我们采用大规模生物物理模型，在多种噪声幅度和刺激位点组合下系统地考察了局部刺激的影响。我们证实，噪声幅度非线性和异质性地调节了刺激效应，从区域和网络两个层面均有所体现。此外，通过整合解剖网络的作用，我们发现，在不同刺激位点处未经刺激区域峰值频率的平均值与结构连接性高度正相关。关键的是，整体功能连接性的变化以及由结构连接性施加的约束的改变与刺激位点的结构度之间的关联，受到噪声幅度的非线性影响，这种关联在特定的噪声幅度范围内增加。此外，认知系统的局部刺激影响取决于噪声幅度与平均结构度的复杂相互作用。总体而言，本研究从理论上揭示了噪声幅度和网络结构如何共同调节刺激期间的脑动力学，并为更好地预测和控制刺激结果提供了可能性。