To understand many complex worm behaviors like copulation of the C. elegans male, reconstruction of the nervous system is required as a basic structural approach. A reconstruction of the adult hermaphrodite nervous system has been available since 1986, but due to the formidable technical challenge of hand reconstruction from electron micrographic prints, no comprehensive projects have been attempted since that time. We have undertaken to determine the structure of the nervous system of the adult male with computer assistance to handle the electron microscopic images. We have developed a customized software program named Elegance (initial version written by Metahelix Life Sciences Pvt Ltd) that facilitates the recording of data from digitized images on the computer screen. Elegance is based on JAVA2 and saves data about the locations of neuron profiles and their synaptic relationships in a MySQL database. Elegance constructs neuron diagrams from the MySQL data tables. Use of Elegance not only speeds the reconstruction process, it also makes possible the reconstruction of complex branched neurons, many of which are found in the male pre-anal ganglion, that were beyond the reach of hand reconstruction methods. We are currently reconstructing the male posterior nervous system, which contains 85 male-specific sensory, inter-, and motorneurons in addition to those neurons also found in the hermaphrodite. In prior work, a set of complete low-power and high-power prints were generated and partially analyzed (Sulston, J.E., Albertson, D.G., and Thomson, J.N. Dev. Biol. 78, 542-576, 1980). Given this valuable dataset, now at Einstein, we have begun by completing this reconstruction project. Our results are posted as they are obtained at
http://worms.aecom.yu.edu (Connectivity) and at
http://wormatlas.org (Individual Neurons). Already it is possible to discern possible synapses and circuits involved in several steps of copulation, including response, spicule prodding and insertion, and ejaculation. Following completion of the posterior nervous system, we plan to cut new sections through the male head and reconstruct the anterior nervous system. The results will allow us to understand how male-specific neurons that grow into the nerve ring target the existing neuropil to control the animals overall behavior. They will also allow us to address the neural basis of such male-specific behaviors as mate-searching and hermaphrodite detection. We hope that continued development of Elegance will increasingly ease the reconstruction process and facilitate further projects, such as reconstruction of the embryonic nervous system of the L1 larva. Elegance is available on request and we welcome additional users.