Mapping of individual sensory nerve axons from digits to spinal cord with the Transparent Embedding Solvent System

Abstract

Understanding the connections and projections of neurons has been a fundamental issue for neuroscience. Although strategies have been developed to map the projection of individual axons within the mouse brain, high resolution mapping of individual peripheral nerve axons in peripheral organs or spinal cord has never been achieved. Here, we designed the Transparent Embedding Solvent System (TESOS) method and developed a technical pipeline for imaging, reconstructing and analyzing large samples containing various tissue types at sub-micron resolution. The mouse whole body was reconstructed at micron-scale resolution. We were able to image, reconstruct and analyze the complete axonal projection of individual sensory neurons within an intact mouse paw or spinal cord at sub-micron resolution. Furtherly, we imaged and reconstructed the entire projection course of individual sensory neurons from adult mouse digits to the spinal cord. The TESOS method provides an efficient tool for micron-scale connectome mapping of the peripheral nervous system.