2464 - Network structure of the mouse brain connectome with voxel resolution
Background: Comprehensive descriptions of brain connectivity are fundamental for understanding how neural information is processed and relayed across spatial scales. Prior investigations of the mouse brain connectome have employed predefined subsets of anatomical parcellations, limiting spatial resolution and potentially concealing sub-regional attributes critical to the organization of mammalian connectomes.
Aim: Here we provide a voxel-level description of the network and hierarchical structure of the directed mouse connectome, unconstrained by regional partitioning.
Methods: We characterized the modular structure and graph theoretical properties of the mouse connectome, probing network resilience by means of targeted attacks, and used diffusion map embedding to characterize the spatial organization of the structural and functional connectomes, as mapped with resting state fMRI (rsfMRI).
Results: We localized focal set of hub regions that can be directionally segregated into neural sinks and sources, defining a novel hierarchical axis. We also found a set of structural communities that reconstitutes previously described mouse fMRI networks, and discovered that ascending neuromodulatory nuclei are strategically wired as connector hubs and pivotal orchestrators of network communicability. Notably, like in primates, the mouse cortical connectome is organized along two superimposed gradients reflecting unimodal-transmodal functional processing and modality-specific sensorimotor districts. These structural motifs can be related to patterns of intralaminar connectivity and shape the spatial topography of dynamic fMRI states, respectively.
Conclusions: Together, our results reveal a high-resolution structural scaffold linking mesoscale connectome topography to its macroscale functional organization, and create opportunities for identifying targets of interventions to modulate brain function in a physiologically-accessible species.