Morphological Charectization of AHN’s at the Level of Synaptic Partnership in Drosophila melanogaster

Alec Phelps*, Malia Miller, Kevin Daly Ph.D.
Department of Biology, West Virginia University, Morgantown, WV 26506

Presentation Category: Biological Sciences (Poster presentation)

Student’s Major: Biology

A corollary discharge circuit (CDC) is a neural pathway from motor control centers to sensory and motor neuropil. CDCs have been observed in nearly every organism and sensory modality studied to date and typically function to disambiguate internally from externally derived stimulus sources in order to elicit an appropriate behavioral response to the environment. We have described a CDC in insects including Drosophila melanogaster. They are found in pterathoracic neuromere of the insect ventral nerve cord (VNC) and are called ascending histaminergic neurons (AHN’s) because they are histamine immunoreactive and they ascend from the VNC to the brain. The goal of this project is to morphologically identify the AHNs in Drosophila melanogaster at the level of synaptic partnerships and identify pre and postsynaptic partners in the VNC. This is achieved through a serial section transmission-electron microscopy (ssEM) connectomics dataset, in which a reconstruction of the Drosophila VNC neurons can be generated in three-dimensional volumes to classify neurons by structure, as well as labeling of synaptic input and output and identification of up and downstream partners. Morphological characterization of neurons was achieved by elimination methods. We have now traced our AHNs and several synaptic partners in the pterathoracic neuromere. Synaptic partners we traced from the synapse back then characterized as ascending, descending, local or afferent neurons based on specific morphological characteristics. Importantly, by identifying synaptic partners to the AHNs, we can then search Gal 4 driver line databases for functional studies of the relationships between the AHNs and specific partners.

Funding: Air Force Office of Scientific Research

Program/mechanism supporting research/creative efforts: WVU's Research Apprenticeship Program (RAP) & accompanying HONR 297-level course