New tool expands the horizons for neuron sequencing

Ever since 19th-century neuroanatomist Santiago Ramón y Cajal discovered the brain’s beautifully complex neurons—what he referred to as “the mysterious butterflies of the soul”—neuroscientists have sought to characterize the hundreds or thousands of varieties of brain cells and reveal how they work together. It’s a lofty goal, but one that would greatly help neuroscientists finally understand the intricate web of the brain’s circuits—and their function.