AUTHOR=Shih Chi-Tin , Chen Nan-Yow , Wang Ting-Yuan , He Guan-Wei , Wang Guo-Tzau , Lin Yen-Jen , Lee Ting-Kuo , Chiang Ann-Shyn TITLE=NeuroRetriever: Automatic Neuron Segmentation for Connectome Assembly JOURNAL=Frontiers in Systems Neuroscience VOLUME=Volume 15 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/systems-neuroscience/articles/10.3389/fnsys.2021.687182 DOI=10.3389/fnsys.2021.687182 ISSN=1662-5137 ABSTRACT=Segmenting individual neurons from a large number of noisy raw images is the first step in building a comprehensive map of neuron-to-neuron connections for predicting information flow in the brain. Thousands of fluorescence-labeled brain neurons have been imaged. However, mapping a complete connectome remains challenging because imaged neurons are often entangled and manual segmentation of a large population of single neurons is laborious and prone to bias. In this study, we report an automatic algorithm, NeuroRetriever, for unbiased large-scale segmentation of confocal fluorescence images of single neurons in the adult Drosophila brain. NeuroRetriever uses a high-dynamic-range thresholding method to segment single neurons based on branch-specific structural features. With high quality brain images available nowadays, NeuroRetriever allows us to successfully retrieve 28,125 single-neuron images from 22,037 raw brain images validated by human segmentation. Thus, automated NeuroRetriever will greatly accelerate 3D reconstruction of the single neurons for constructing the complete connectomes.