Project description:Neural representations of head direction (HD) have been discovered in many species. Theoretical work has proposed that the dynamics associated with these representations are generated, maintained, and updated by recurrent network structures called ring attractors. We evaluated this theorized structure-function relationship by performing electron microscopy-based circuit reconstruction and RNA profiling of identified cell types in the HD system of Drosophila melanogaster. We identified motifs that have been hypothesized to maintain the HD representation in darkness, update it when the animal turns, and tether it to visual cues. Functional studies provided support for the proposed roles of individual excitatory or inhibitory circuit elements in shaping activity. We also discovered recurrent connections between neuronal arbors with mixed pre- and post-synaptic specializations. Our results confirm that the Drosophila HD network contains the core components of a ring attractor while also revealing unpredicted structural features that might enhance the network’s computational power.
Project description:Samples 1-24: Tissue-specific gene expression microarrays (Nimblegen) using dissected ring glands isolated from FOUR different time points of control (w1118, otherwise wild type) third instar larvae. Time points are 4, 8, 24 and 36 hours after the molt from second to third instar larvae. Samples 25-42: Tissue-specific gene expression microarrays (Nimblegen) using dissected ring glands isolated from TWO different time points of third instar larvae. Genotypes were phantom22-GAL4/RasV12 and phantom22/Torso-RNAi. Goal was to identify PTTH-dependent gene sets in the ring gland. Time points were 18 hours and 8 hours prior to puparium formation.