Meeting Abstract
Animals exhibit an astonishing array of complex behaviors whose neural underpinnings remain largely unknown. In most animals, the brain affects these behaviors through communication with motor centers in the body through a set of Descending Neurons (DNs) that traverse the neck. We studied the role of DNs on flight control in the fruit fly Drosophila melanogaster. Using cell-type specific driver lines we generated that target individual DNs, we leveraged optogenetics, calcium imaging and electrophysiology to interrogate the function of Flight Descending Neurons (FDNs) innervating the wing and haltere neuropils in the ventral nervous system. We found unique FDNs with bilateral pairs and population FDNs that form small groups of cells with nearly identical arbors. One population of FDNs, DNg02, contained up to fifteen pairs of morphologically identical neurons. By systematically activating subsets of these FDNs using CsChrimson, we observed changes in wingbeat amplitude and frequency during tethered flight. Although the wingbeat amplitude was directly proportional to the number of FDNs activated, frequency changes depended on the frequency level prior to activation up to a specific setpoint. These results, as well as calcium imaging, show unilateral activity of these cells in response to visual stimuli and suggests the use of population coding for flight control by the FDNs for modulating not only thrust responses during flight but also turning.
