Optical interrogation of multi-scale neuronal plasticity underlying behavioral learning

• Published in: Current opinion in neurobiology 2021-04, Vol.67, p.8-15
• Main Authors: Tsutsumi, Shinichiro, Hayashi-Takagi, Akiko
• Format: Article
• Language: English
• ISSN: 0959-4388; 1873-6882
• DOI: 10.1016/j.conb.2020.07.002

•A link between synaptic and neural circuit plasticity remains to be elucidated.•Novel tools have been developed to monitor and manipulate synaptic plasticity.•Large-scale imaging of circuit plasticity can be at synapse-level resolution.•Multiscale optical interrogation links synaptic and circuit plasticity. 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.