Stephen Plaza’s research paper published in Nature Scientific Journal

Stephen Plaza (CSE PhD 2008) co-authored a paper published in Nature entitled, “A visual motion detection circuit suggested by Drosophila connectomics”.

Plaza’s paper provides key insights into neuronal computations. The authors state, “Animal behavior arises from computations in neuronal circuits, but our understanding of these computations has been frustrated by the lack of detailed synaptic connection maps, or connectomes. For example, despite intensive investigations over half a century, the neuronal implementation of local motion detection in the insect visual system remains elusive.”

They developed a semi-automated pipeline using electron microscopy to reconstruct a connectome, then assigned neurons to cell types and assembled a connectome of the repeating module of the medulla. Within this module, they identified cell types constituting a motion detection circuit, and showed that the connections onto individual motion-sensitive neurons in this circuit were consistent with their direction selectivity. The results identified cellular targets for future functional investigations, and demonstrated that connectomes can provide key insights into neuronal computations.

The researchers’ motion detection and the drosophila visual system. a) Rightward motion component of the Hassenstein–Reichardt EM model.  b) Alternative Barlow–Levick-like EMD model, also preferring rightward motion. c) Bodian silver-stained horizontal section of the Drosophila melanogaster visual system revealing the four neuropils of the optic lobe. The medulla region of interest (solid rectangle, expanded in d) and the wider imaged volume (dashed rectangle) used to trace into the lobula plate are shown schematically.

Stephen Plaza graduated Summa Cum Laude with a BSE in computer engineering in 2003 and received his PhD in 2008 in computer science and engineering at the University of Michigan. His areas of expertise were computer architecture, wiring and transistor-level chip optimization, and computational algorithms. In 2010, Stephen decided to combine his experience in computer programming, electrical circuits, logic simulation, and parallel computation and algorithms by working at Janelia Farms for the FlyEM project. In early 2012, Stephen became the project manager for FlyEM. His main goals are to explicitly define and monitor all project requirements and encourage greater synergy between the large, inter-disciplinary team that composes FlyEM.

Plaza’s dissertation co-advisors were Professors Igor Markov and Valeria Bertacco.