We ask how new brain regions and cell types form in evolution, how they connect to the rest of the brain, and what this tells us about the organizing principles and function of the vertebrate brain. We focus on the cerebellar nuclei, the output structures of the cerebellum, which have increased in number across vertebrate lineages. Based on transcriptomic evidence from amniotes, we recently proposed that new brain regions form by a process of duplication and divergence of a deeply conserved cell type set. We are now extending these findings to define the molecular makeup of the ancestral cerebellar nucleus by spatial sequencing in amphibians and lungfish and by investigating cerebellar nuclei development. To understand how newly formed nuclei are integrated into brain-wide circuits, we develop barcoded connectomics techniques, including MAPseq and BRICseq, to map neuronal connectivity at single-cell resolution and with transcriptomic annotation. We present new technologies to map single-cell projections of defined cell types and to map connectivity at single-cell resolution across vertebrates ranging from amphibians to monkeys and apply them to the cerebellar nuclei.
Organizer
Xiaolu Wang
x.wang@erasmusmc.nl