Liu, C. et al. Nat. Neurosci. 23, 271–280 (2020).
A detailed description of white matter pathways is paramount for studying connectivity in healthy and diseased primate brains, yet high-resolution atlases of white matter have so far not been available. Liu et al. have built such an atlas for the marmoset. With its small size, the ex vivo marmoset brain could be imaged using high-field MRI and strong gradients. Through optimizing the MRI hardware as well as the scanning protocol and sample preparation, the researchers obtained diffusion-weighted MRI datasets with up to 64-micrometer isotropic resolution, which is unprecedented for primate brains. Owing to the high resolution, the researchers could visualize fine details of fiber pathways that had not been accessible before. Furthermore, the researchers integrated their white matter atlas with a previously acquired atlas of gray matter, as well as with a neuronal tracing database to further increase the value of the atlas. The atlas can be accessed at https://marmosetbrainmapping.org.