The mammalian brain is a bustling hub of intricate webs of billions of neurons connected by a network of neural highways with signals racing along winding routes. Researchers have sought to understand the nitty gritty details of this complex organ for a while.

With this target, scientists from a number of institutes launched the BRAIN Initiative Cell Atlas Network (BICAN) a few years ago. “The main goal of this was to leverage single cell genomics technologies to profile millions of cells in the mammalian brain,” said Hongkui Zeng, an investigator at the Allen Institute.

Now, in a step toward that direction, Zeng and hundreds of other researchers from dozens of institutes across nine countries joined forces to unveil a multi-species cellular atlas of the basal ganglia: structures at the base of the forebrain. The findings, which were published today in a package of 26 studies in Cell Press journals, represent the most detailed library of basal ganglia to date, offering a resource to better understand brain cell characteristics and how diseases affect these.