Behavioral learning is driven by adaptive changes in the activation of behaviorally relevant neuronal ensembles. This learning-specific reorganization of neuronal circuits is correlated with activity-dependent modifications of synaptic dynamics. However, a definitive causal link remains to be established. How is synaptic plasticity distributed among circuits to eventually shape behavioral learning? A multi-scale understanding of the progressive plasticity is hindered by the lack of techniques for monitoring and manipulating these events. The current rise of synaptic optogenetics, especially combined with brain-wide circuit imaging, opens an entirely new avenue for studying causality at multiple scales. In this review, we summarize these technical achievements and discuss challenges in linking the plasticity across levels to elucidate the multi-scale mechanisms of learning.

行为学习是由行为相关神经元集成的激活中的适应性变化驱动的。神经回路的这种学习特定的重组与突触动力学的活动依赖的修改相关。但是，明确的因果关系仍有待建立。突触可塑性如何在电路之间分配以最终塑造行为学习？缺乏用于监视和操纵这些事件的技术阻碍了对渐进可塑性的多尺度理解。突触光遗传学的兴起，特别是与全脑电路成像相结合，为研究多尺度的因果关系开辟了一条全新的途径。在这篇评论中