In the visual system, peripheral processing circuits are often tuned to specific stimulus features. How this selectivity arises and how these circuits are organized to inform specific visual behaviors is incompletely understood. Using forward genetics and quantitative behavioral studies, we uncover an input channel to motion detecting circuitry in Drosophila. The second-order neuron L3 acts combinatorially with two previously known inputs, L1 and L2, to inform circuits specialized to detect moving light and dark edges. Invivo calcium imaging of L3, combined with neuronal silencing experiments, suggests a neural mechanism to achieve selectivity for moving dark edges. We further demonstrate that different innate behaviors, turning and forward movement, can be independently modulated by visual motion. These two behaviors make use of different combinations of input channels. Such modular use of input channels to achieve feature extraction and behavioral specialization likely represents a general principle in sensory systems
Bibliographical noteFunding Information:
We thank Nirao Shah, Liqun Luo, Christian Klämbt, David Kastner, Girish Deshpande, Saskia de Vries, Jennifer Esch, and Tina Schwabe for critical comments on the manuscript. We thank Georg Dietzl and Sheetal Bhalerao for providing the phototaxis assay, Christoph Scheper and Ya-Hui Chou for brain dissections, and Alexander Katsov for help with the high-throughput behavioral assay. M.S. and D.A.C. acknowledge postdoctoral fellowships from the Jane Coffin Childs Memorial Fund for Medical Research. D.M.G was supported by a Ruth L. Kirschstein NRSA Postdoctoral Fellowship (F32EY020040) from the National Eye Institute. Y.E.F. acknowledges an NIH Neuroscience Research Training grant (5 T32 MH020016-14), and L.F. was supported by a Fulbright International Science and Technology Scholarship and a Bio-X Stanford Interdisciplinary Graduate Fellowship (Bruce and Elizabeth Dunlevie fellow). D.A.C also received support from an NIH T32 Postdoctoral Training Grant. This work was funded by a National Institutes of Health Director’s Pioneer Award DP1 OD003530 (T.R.C.) and by R01 EY022638.