A Pipeline for a Primate Projectome: mapping every individual myelinated axon across the whole brain

We developed a pipeline to detail the morphology and complete trajectory of every long distance projecting neuron in large volumes of the non-human primate brain - a projectome. A projectome would organize how the hundreds of brain regions in a primate brain communicate with each other and provide a comprehensive classification of long distance neurons. The reason such projectomes do not exist already is that there is no single imaging technique with the resolution and sampling depth capable of producing one in primates. Here we address that gap by combining new ways to cut brains with minimal tissue loss, nanoscale x-ray microscopy imaging that reveals every individual myelinated axon (MA) and the location, size, and morphology of every neuron, and algorithms for tracing individual myelinated axons for millimeters to centimeters, across tissue gaps.