Allen mouse brain atlases reveal different neural connection and gene expression patterns in cerebellum gyri and sulci.

The recently released Allen Mouse Brain Connectivity Atlas provides a comprehensive mouse brain neuronal connectivity map from brain-wide injection sites via anterograde tracers coupled with serial two-photon tomography. In addition, the Allen Mouse Brain Atlas offers a genome-wide gene expression database built upon a series of in situ hybridization images, covering comprehensive expression energy of over 4,000 genes in coronal sections and over 20,000 genes in sagittal sections across the whole mouse brain. These concurrent and co-registered datasets provide an unparalleled opportunity for systematically analyzing and characterizing spatial neuronal connectivity and gene expression patterns. Inspired by our recent macroscale neuroimaging results showing that there are significantly different structural and functional connectivity patterns on the gyri and sulci of cerebral cortex in primate brains, the present work systematically examines the axonal connectivity and gene expression patterns on gyri and sulci of the cerebellum. Our results demonstrate that the cerebellum gyri and sulci of rodent brains are significantly different in both axonal connectivity and gene expression patterns. This discovery enriches and extends our prior findings in macroscale neuroimaging studies in primates. Additionally, this work offers novel insights on the molecular and structural architectures of the cerebellum in particular and the brain in general.