| Description |
Determining the ultrastructural organization of the nervous system is a key step in understanding how complex behavior is generated. For a nervous system to function, it must be wired accurately. A complete wiring diagram, referred to as a connectome, can be created by tracing neuronal profiles through serial images. Though transmission electron microscopy (TEM) provides the necessary resolution to image small synapses, serial imaging for reconstruction generates a very large electron micrograph data set. Manually reconstructing these micrographs into a three dimensional volume would require an unrealistic amount of time and manpower. Therefore, in an effort to increase the efficiency of this process we have developed a semi-automated method to reconstruct a portion of the ventral nerve cord in the nematode, Caenorhabditis elegans. In this emiautomated reconstruction, the computer programs detect, segment, and link neural membranes from hundreds of electron micrographs into a single three-dimensional volume. The connectivity was comparable to the manually generated connectivity map, suggesting the potential efficiency and accuracy of this procedure. In addition to understanding the connectivity of the nervous system, the anatomy of neural ultrastructure is equally important. Specifically, we quantitatively tested the theory of microtubule continuity in the synapse. By manually reconstructing neural microtubules in a portion of the C. elegans ventral nerve cord, we calculated the average microtubule length to be 0.53 ^m. Though microtubule length varies depending on the neuron, its size is relatively short compared to the neuronal process, creating a staggered discontinuous network extending from cell body through the synapse. |
