Title: Symmetry Breaking in Neuronal Development
Description: Many physical systems break symmetry in their evolution. Biophysical systems, such as cells, developing organisms, and even entire populations, are no exception. Developing neurons represent a striking example of a biophysical system that breaks symmetry: neurons cultured in vitro begin as cell bodies with several tendrils (&ldquo;neurites&rdquo;) growing outward. A few days later, these same neurons invariably have the same new morphology: exactly one of the neurites (the &ldquo;axon&rdquo;) has grown hundreds of microns in length, while the others (the "dendrites") are much shorter and are more branched. Previous work has shown that any of the neurites can become the axon, and so neurons must break symmetry during their development. The mechanisms underlying neuronal symmetry breaking and axon specification have recently attracted attention, with multiple groups proposing biophysical models to explain the phenomena.