Monosynaptically-interconnected Network Module (MNM) Approach for High-Resolution Brain Sub-Network Analysis
We introduce the Monosynaptically-interconnected Network Module (MNM) approach, an innovative method designed for efficiently analyzing the anatomical structure and functional dynamics of specific brain network modules in vivo. Utilizing an Intein-mediated split-Cre system combined with bidirectional adeno-associated viruses, this technique precisely targets and manipulates monosynaptically interconnected modular subnetworks in freely moving animals. We demonstrate its utility through anatomical and functional mapping of a specific MNM encompassing the prefrontal cortex (PFC), basolateral amygdala (BLA), and intermediary hub regions. Specifically, the MNM approach with Cre-reporter mice visualizes detailed network architecture and traces axonal connections among the nodes of the network. Additionally, combining the MNM approach with Cre-dependent Ca2+ indicator and multi-fiber photometry reveals enhanced correlative network activities in social contexts. This versatile technique offers significant potential for advancing our understanding of network functions that underlie complex behaviors, providing a modular network perspective.