@article {68838, title = {Small-field visual projection neurons detect translational optic flow and support walking control}, journal = {bioRxiv}, year = {2023}, month = {2023 Jun 22}, abstract = {

Animals rely on visual motion for navigating the world, and research in flies has clarified how neural circuits extract information from moving visual scenes. However, the major pathways connecting these patterns of optic flow to behavior remain poorly understood. Using a high-throughput quantitative assay of visually guided behaviors and genetic neuronal silencing, we discovered a region in\ Drosophila{\textquoteright}s protocerebrum critical for visual motion following. We used neuronal silencing, calcium imaging, and optogenetics to identify a single cell type, LPC1, that innervates this region, detects translational optic flow, and plays a key role in regulating forward walking. Moreover, the population of LPC1s can estimate the travelling direction, such as when gaze direction diverges from body heading. By linking specific cell types and their visual computations to specific behaviors, our findings establish a foundation for understanding how the nervous system uses vision to guide navigation.

}, doi = {10.1101/2023.06.21.546024}, url = {https://doi.org/10.1101/2023.06.21.546024}, author = {Mathew D. Isaacson and Jessica L. M. Eliason and Aljoscha Nern and Edward M. Rogers and Gus K. Lott and Tanya Tabachnik and William J. Rowell and Austin W. Edwards and Wyatt L. Korff and Gerald M. Rubin and Kristin Branson and Michael B. Reiser} } @article {68570, title = {Eye structure shapes neuron function in Drosophila motion vision}, journal = {bioRxiv}, year = {2022}, month = {2022 Dec 15}, abstract = {

Many animals rely on vision to navigate through their environment. The pattern of changes in the visual scene induced by self-motion is the\ optic flow1, which is first estimated in local patches by directionally selective (DS) neurons2{\textendash}4. But how should the arrays of DS neurons, each responsive to motion in a preferred direction at a specific retinal position, be organized to support robust decoding of optic flow by downstream circuits? Understanding this global organization is challenging because it requires mapping fine, local features of neurons across the animal{\textquoteright}s field of view3. In\ Drosophila, the asymmetric dendrites of the T4 and T5 DS neurons establish their preferred direction, making it possible to predict DS responses from anatomy4,5. Here we report that the preferred directions of fly DS neurons vary at different retinal positions and show that this spatial variation is established by the anatomy of the compound eye. To estimate the preferred directions across the visual field, we reconstructed hundreds of T4 neurons in a full brain EM volume6\ and discovered unexpectedly stereotypical dendritic arborizations that are independent of location. We then used whole-head μCT scans to map the viewing directions of all compound eye facets and found a non-uniform sampling of visual space that explains the spatial variation in preferred directions. Our findings show that the organization of preferred directions in the fly is largely determined by the compound eye, exposing an intimate and unexpected connection between the peripheral structure of the eye, functional properties of neurons deep in the brain, and the control of body movements.

}, doi = {10.1101/2022.12.14.520178}, url = {https://doi.org/10.1101/2022.12.14.520178}, author = {Arthur Zhao and Eyal Gruntman and Aljoscha Nern and Nirmala A. Iyer and Edward M. Rogers and Sanna Koskela and Igor Siwanowicz and Marisa Dreher and Miriam A. Flynn and Connor W. Laughland and Henrique D.F. Ludwig and Alex G. Thomson and Cullen P. Moran and Bruck Gezahegn and Davi D. Bock and Michael B. Reiser} }