Lymphatics help 'seed' early brain cells in zebrafish
During the embryonic stage of brain development, some neurons and synapses are well formed and connected, but others are not, causing some parts and parts to be discarded. This leaves dead or dying cells and requires the central nervous system to employ some kind of cleaning crew. Microglial cells take up the challenge, “swallow” waste, and are therefore essential for brain development. However, scientists don’t have a full understanding of how they populate the brain. A recent paper in Nature Neuroscience by University of Notre Dame biologist Cody J. Smith shows how lymphatics – which remove waste from other parts of the body – are also linked to microglia and brain development in zebrafish. “Microglia, we know, are born outside the brain but somehow have to enter the brain during development, which is called colonization,” said Smith, Elizabeth and Michael Gallagher Associate Professor in the Department of Biological Sciences. “We know that in humans this colonization is present