Study discovers simple rules underlying complex brain development in fly

By UCSF School of Pharmacy Editorial Staff / Mon Jun 29, 2015

Langen et al. / Cell 2015

A fruit fly’s compound eye contains 800 prism-like facets whose six distinct photoreceptor cells capture light coming in from different angles in space. These signals must all find their way to different spots in the fly brain’s visual map of the world.

How does brain circuitry organize itself during development? In at least one case—the seemingly complex visual system of the fruit fly, which connects its 800-facet compound eyes to its brain—the answer lies in just three simple rules.

The discovery, which unravels a trick of neural wiring that had stumped neuroscientists for decades, is described in a new paper senior-co-authored by UCSF School of Pharmacy faculty members Steven Altschuler, PhD, and Lani Wu, PhD, and Peter Robin Hiesinger, PhD, a faculty member with Freie Universität Berlin. The paper, “The Developmental Rules of Neural Superposition in Drosophila,” is available online in advance of its print publication in the July 2 issue of the journal Cell.

The algorithms were based on a combination of high-resolution time-lapse imaging of the developing brains of pupal fruit flies (aka the model organisms, Drosophila melanogaster) by the paper’s Germany-based co-authors and data-driven computational modeling by the U.S.-based co-authors.

This discovery “gives us hope that maybe one day we can really understand other complex biological systems in terms of simple rules,” said Wu. She and Altschuler are faculty members in the School’s Department of Pharmaceutical Chemistry.

Three Simple Rules Govern Complex Brain Circuit in Fly