Serial-Section Electron Microscopy for Analysis of Organization of Retinal Axons

Professor Chi-Bin Chien

This project addresses the analysis of serial-section electron microscopy data for the analysis of axons. Serial section microscopy is one of the most compelling examples of this gap between the technology for image acquisition and the technology for image analysis. Biological scientists can produce images faster than they can analyze them. The answers to many important biological questions depend on a better understanding of cellular anatomy, and detailed, data-driven descriptions of microscopic structures are especially important in neurobiology. Dr. Chi-Bin Chien (Associate Professor of Neurobiology and Anatomy) addresses axonal path finding and patterning in the optic nerve in his research.

Dr. Chien's Lab studies retinal axon guidance in the zebrafish visual system, and has recently started to elucidate the mechanisms of topographic sorting of axons in the optic tract. Using genetic, biochemical, and confocal microscopic analysis of the boxer and dackel mutants, the Chien Lab has shown that heparan sulfate proteoglycan (HSPG) synthesis is disrupted in these mutants, and thereby, showed a specific requirement for HSPGs in sorting of dorsal retinal axons. Indeed, recent studies show that HSPGs play important roles in axon guidance in several organisms. It has long been clear that interactions between axons are important, but direct observation of axon-axon interactions in vivo has been technically difficult.