High-speed mapping of whole-mouse peripheral nerves at subcellular resolution

Abstract In contrast to the rapid advancements in mesoscale connectomic mapping of the mammalian brain, similar mapping the peripheral nervous system has remained challenging due to the body’s size and complexity. Here, we present a high-speed blockface volumetric imaging system with an optimized workflow of whole-body clearing, capable of imaging the entire adult mouse at micrometer resolution within 40 hours. Three-dimensional reconstruction of individual spinal fibers in Thy1-EGFP mice reveals distinct morphological features of sensory and motor projections along the ventral and dorsal rami. Immunostaining facilitates body-wide mapping of sympathetic nerves and their branches, highlighting their perivascular patterns in limb muscles, bones, and most visceral organs. Viral tracing elucidates the fine architecture of vagus nerves and individual vagal fibers, revealing unexpected projection routes to various organs. Our approach offers an effective means to achieve a holistic understanding of cellular-level interactions among different systems that underlie body physiology and disease. Highlights Imaging of whole adult mouse at uniform subcellular resolution within 40 hours Reconstruction of 191 thoracic spinal neuron projections for Thy1-EGFP mice Mapping of immunolabeled sympathetic projections and their perivascular patterns Resolving virus-labeled architecture of vagus nerves and complex single-fiber routes