In two recent papers involving the roundworm C. elegans, Hannes E. Buelow, Ph.D., and colleagues shed light on how neural networks are assembled during development. Dendrites are string-like extensions of neurons that sample the environment or connect with other neurons at junctions called synapses. Electrical impulses from a neuron’s dendrites are conveyed by the neuron’s other long projection—its axon—to the next neuron in the network. Sensory nerves often form elaborately branched dendritic trees, or “arbors,” so that they can collect information or sample the environment appropriately. Researchers have long known that an axon’s neuronal activity can shape the dendrites of neurons with which they are connected. In a study published on January 17 in Developmental Cell, Dr. Buelow and his team report that axons can also shape dendrites of certain C. elegans sensory neurons, known as PVD neurons, by acting as scaffolds; the researchers identified several conserved genes involved in this process. The second paper, which published January 29 in eLife, uncovers an additional mechanism involved in forming dendritic arbors. Dr. Buelow and colleagues describe how three different proteins interact within the extracellular matrix to help form the PVD dendrites and regulate the growth of dendritic branches. Psychiatric conditions such as autism spectrum disorders and schizophrenia may result from incorrectly interconnected neural networks. So defects in any one or more of these conserved genes, or in genes coding for the interacting proteins, may be a cause of those disorders. Dr. Buelow is professor of genetics and in the Dominick P. Purpura Department of Neuroscience at Einstein.
Posted on: Wednesday, February 13, 2019