The brain shows a complex multiscale organization that prevents a direct understanding of how structure, function and dynamics are correlated. To date, advances in neural modeling offer a unique opportunity for simulating global brain dynamics by embedding empirical data on different scales in a mathematical framework. The Virtual Brain (TVB) is an advanced data-driven model allowing to simulate brain dynamics starting from individual subjects’ structural and functional connectivity obtained, for example, from magnetic resonance imaging (MRI). The use of TVB has been limited so far to cerebral connectivity but here, for the first time, we have introduced cerebellar nodes and interconnecting tracts to demonstrate the impact of cerebro-cerebellar loops on brain dynamics. Indeed, the matching between the empirical and simulated functional connectome was significantly improved when including the cerebro-cerebellar loops. This positive result should be considered as a first step, since issues remain open about the best strategy to reconstruct effective structural connectivity and the nature of the neural mass or mean-field models generating local activity in the nodes. For example, signal processing is known to differ remarkably between cortical and cerebellar microcircuits. Tackling these challenges is expected to further improve the predictive power of functional brain activity simulations, using TVB or other similar tools, in explaining not just global brain dynamics but also the role of cerebellum in determining brain states in physiological conditions and in the numerous pathologies affecting the cerebro-cerebellar loops.

大脑显示出复杂的多尺度组织，阻碍了对结构、功能和动力学如何相互关联的直接理解。迄今为止，神经建模的进步为通过在数学框架中嵌入不同尺度的经验数据来模拟全球大脑动力学提供了独特的机会。虚拟大脑 (TVB) 是一种先进的数据驱动模型，允许从单个受试者的结构和功能连接（例如从磁共振成像 (MRI) 获得）开始模拟大脑动态。迄今为止，TVB 的使用仅限于大脑连接，但在这里，我们首次引入了小脑节点和互连束，以证明大脑-小脑环路对大脑动力学的影响。事实上，当包括脑-小脑环时，经验和模拟功能连接组之间的匹配显着改善。这一积极结果应被视为第一步，因为关于重建有效结构连接的最佳策略以及在节点中产生局部活动的神经质量或平均场模型的性质的问题仍然存在。例如，已知皮质微电路和小脑微电路之间的信号处理存在显着差异。应对这些挑战预计将进一步提高功能性大脑活动模拟的预测能力，使用 TVB 或其他类似工具，不仅可以解释全局大脑动力学，还可以解释小脑在确定生理条件下的大脑状态和影响大脑的众多病理学中的作用。大脑-小脑环路。