Functional dissection of the neural substrates for gravitaxic maze behavior in Drosophila melanogaster.

In animals, sensing gravity is supported by mechanosensory neurons that send information to the central brain for integration along with other modalities. In Drosophila, candidate sensory organs for detecting the gravity vector were predicted from the results of a recent forward genetic screen. This analysis also suggested possible roles for the central complex and antennal system in Drosophila. Using the same vertical maze assay employed in the original screen, we investigated the roles of these candidate neural structures by spatial and temporal inactivation of synaptic transmission with the GAL4/UAS-shibire[ts1] system. We correlate changes in the maze behavior of flies with specific inhibition of synaptic transmission for key brain neuropil that includes the central complex and antenno-glomerular tract. Further, our results point toward a minimal, or nonexistent, role for the mushroom bodies.