QIMR Berghofer Medical Research Institute, Brisbane, Australia.
QIMR Berghofer Medical Research Institute, Brisbane, Australia; Centre of Excellence for Integrative Brain Function, QIMR Berghofer Medical Research Institute, Brisbane, Australia.
Neuroimage. 2017 Oct 15;160:97-112. doi: 10.1016/j.neuroimage.2017.01.057. Epub 2017 Jan 24.
The human brain exhibits a distinct spatiotemporal organization that supports brain function and can be manipulated via local brain stimulation. Such perturbations to local cortical dynamics are globally integrated by distinct neural systems. However, it remains unclear how local changes in neural activity affect large-scale system dynamics. Here, we briefly review empirical and computational studies addressing how localized perturbations affect brain activity. We then systematically analyze a model of large-scale brain dynamics, assessing how localized changes in brain activity at the different sites affect whole-brain dynamics. We find that local stimulation induces changes in brain activity that can be summarized by relatively smooth tuning curves, which relate a region's effectiveness as a stimulation site to its position within the cortical hierarchy. Our results also support the notion that brain hubs, operating in a slower regime, are more resilient to focal perturbations and critically contribute to maintain stability in global brain dynamics. In contrast, perturbations of peripheral regions, characterized by faster activity, have greater impact on functional connectivity. As a parallel with this region-level result, we also find that peripheral systems such as the visual and sensorimotor networks were more affected by local perturbations than high-level systems such as the cingulo-opercular network. Our findings highlight the importance of a periphery-to-core hierarchy to determine the effect of local stimulation on the brain network. This study also provides novel resources to orient empirical work aiming at manipulating functional connectivity using non-invasive brain stimulation.
人类大脑表现出独特的时空组织，支持大脑功能，并可以通过局部脑刺激进行操作。这种对局部皮质动力学的干扰被不同的神经系统全局整合。然而，目前尚不清楚神经活动的局部变化如何影响大规模系统动力学。在这里，我们简要回顾了一些解决局部扰动如何影响大脑活动的经验和计算研究。然后，我们系统地分析了一个大规模大脑动力学模型，评估了大脑活动在不同部位的局部变化如何影响整个大脑的动力学。我们发现，局部刺激会引起大脑活动的变化，这些变化可以用相对平滑的调谐曲线来概括，该曲线将一个区域作为刺激部位的有效性与其在皮质层次结构中的位置联系起来。我们的结果还支持这样一种观点，即大脑枢纽以较慢的速度运作，对焦点扰动更具弹性，并对维持全局大脑动力学的稳定性至关重要。相比之下，以较快活动为特征的外围区域的扰动对功能连接的影响更大。作为与这一区域水平结果的平行，我们还发现，外围系统（如视觉和感觉运动网络）比高级系统（如扣带-前运动网络）更容易受到局部扰动的影响。我们的研究结果强调了从外围到核心的层次结构对于确定局部刺激对大脑网络影响的重要性。这项研究还为旨在使用非侵入性脑刺激来操纵功能连接的实证工作提供了新的资源。
