{"id":126,"date":"2022-02-06T14:51:14","date_gmt":"2022-02-06T14:51:14","guid":{"rendered":"https:\/\/robustcircuit.flygen.org\/?page_id=126"},"modified":"2025-12-13T23:25:31","modified_gmt":"2025-12-13T23:25:31","slug":"project-3","status":"publish","type":"page","link":"https:\/\/robustcircuit.flygen.org\/?page_id=126","title":{"rendered":"Project 3"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\" id=\"robustcircuit-project-3\"><em>RobustCircuit <\/em><strong>Project 3<\/strong><\/h2>\n\n\n\n<p id=\"robustcircuit-project-3\" class=\"wp-block-paragraph\"><em>Funding Period 2022-2026 Project. Updates on new 2026-2030 project to follow soon!<\/em><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-8f761849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-vertically-aligned-center is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:66.66%\">\n<h3 class=\"wp-block-heading\" id=\"from-spatiotemporal-restriction-of-imprecise-synaptic-partner-choice-to-a-robust-representation-of-navigational-information-in-the-fly-brain\">From spatiotemporal restriction of imprecise synaptic partner choice to a robust representation of navigational information in the fly brain<\/h3>\n\n\n\n<h6 class=\"wp-block-heading\" id=\"mathias-wernet\">Mathias Wernet<\/h6>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:33.33%\"><div class=\"wp-block-image is-style-rounded\">\n<figure class=\"aligncenter size-full is-resized\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"202\" height=\"283\" src=\"https:\/\/i0.wp.com\/robustcircuit.flygen.org\/wp-content\/uploads\/2022\/02\/MathiasWernet.jpg?resize=202%2C283&#038;ssl=1\" alt=\"\" class=\"wp-image-115\" style=\"width:101px;height:142px\"\/><\/figure>\n<\/div><\/div>\n<\/div>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"project-3-focuses-on-the-role-of-morphological-variability-and-positional-strategies-of-dynamic-axon-dendritic-interactions-to-restrict-an-inherently-imprecise-capacity-to-form-synapses-between-functionally-specialized-partners\">Project 3 focuses on the role of morphological variability and positional strategies of dynamic axon-dendritic interactions to restrict an inherently imprecise capacity to form synapses between functionally specialized partners.<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">Imprecision: <em>Drosophila<\/em> photoreceptors exhibit stochastic filopodial exploration behavior and can promiscuously form synapses with wrong partners. At the same time, their post-synaptic partners are morphologically diverse, making it impossible to predict their exact tuning properties at a single cell level.<\/p>\n<\/blockquote>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">Robustness: \u00a0Photoreceptor subtypes detecting skylight polarization make synaptic connections with three distinct postsynaptic partner neuron types, while avoiding contacts with color-sensitive counterparts. On a neuron population level, skylight polarization is represented with robustness to variable neuronal morphologies and presumably also to difficult stimulus conditions.<\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">Hypothesis: Restricted filopodial interactions in time and space ensure differential synapse formation of closely related color- and polarization-sensitive photoreceptor neurons that need not otherwise specify their partner choices. Heavily overlapping, morphologically diverse cell types ensure a robust distribution of synapses (and therefore skylight information) across the entire neuronal population.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"project-summary\">Project Summary<\/h4>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"alignleft size-full is-resized\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/i0.wp.com\/robustcircuit.flygen.org\/wp-content\/uploads\/2022\/02\/P3-2.jpg?resize=500%2C500&#038;ssl=1\" alt=\"\" class=\"wp-image-154\" style=\"width:375px;height:375px\" srcset=\"https:\/\/i0.wp.com\/robustcircuit.flygen.org\/wp-content\/uploads\/2022\/02\/P3-2.jpg?w=500&amp;ssl=1 500w, https:\/\/i0.wp.com\/robustcircuit.flygen.org\/wp-content\/uploads\/2022\/02\/P3-2.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/robustcircuit.flygen.org\/wp-content\/uploads\/2022\/02\/P3-2.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><figcaption class=\"wp-element-caption\">Polarization-specific interneurons in the optic lobe<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">Closely related neuronal subtypes neighboring each other in the adult brain often exhibit highly specific, divergent connectivity. Modality-specific photoreceptor neurons and their synaptic partners in the <em>Drosophila<\/em> visual system represent an instance of this phenomenon:&nbsp; While the main portion of the eye and underlying optic neuropils process motion- and color-specific visual input, the dorsal rim area (DRA) processes skylight polarization, ultimately leading to a representation of navigational information in the central brain that is robust over a variety of stimulus conditions. P3 is motivated by our recent team effort of <em>RobustCircuit<\/em> PIs which discovered that color-sensitive R7 neurons readily form synaptic connections with incorrect partners upon contact, ensuring synaptic specificity in the developing wild type brain by separated synaptogenic interactions in time and space. In <strong>P3<\/strong>, we therefore directly compare the selective targeting of DRA photoreceptors R7 and R8 to their specific downstream neurons which process skylight cues, to their color-sensitive counterparts. Based on our preliminary data on neurons in the DRA region, <strong>we hypothesize that the robust representation of information processed by DRA neurons are based on their ability to form synapses promiscuously through the differential regulation of synaptogenic encounters in space and time<\/strong>. <strong>P3<\/strong> is devised to test this hypothesis using three complementary approaches: (i) the quantitative investigation of filopodial dynamics of both pre- and postsynaptic cell types via multi-photon <em>ex vivo<\/em> imaging; (ii) the quantification of variability of neuronal morphology and synaptic distribution by EM-based connectomics; (iii) the quantification of variability and imprecision for creating robust cellular responses, both on a single cell-, as well as on a bulk level, using optophysiology (calcium imaging). Both (i) and (iii) will include wild type brains, as well as targeted manipulations to disrupt filipodial dynamics and neuronal encounters. We will then expand these studies towards neurons that connect the optic lobes with the central brain leading to a robust topographic representation of skylight information there. When these studies are concluded, we will have established a complete 4-dimensional description of the mechanisms for the development of a robust representation of navigational information based on stochastic dynamics in an intact brain.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"references\">References<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li class=\"\">Kind, E., Kind E, Longden KD, Nern A, Zhao A, Sancer G, Flynn MA, Laughland CW, Gezahegn B, Ludwig HD, Thomson AG, Obrusnik T, Alarc\u00f3n PG, Dionne H, Bock DD, Rubin GM, Reiser MB, <strong>Wernet MF.<\/strong> (2021). Synaptic targets of photoreceptors specialized to detect color and skylight polarization in <em>Drosophila<\/em>. <em><strong>elife <\/strong><\/em>10:e71858.<\/li>\n\n\n\n<li class=\"\">Sancer, G. and <strong>Wernet, M.F.<\/strong> (2021). The development and function of neuronal subtypes processing color and skylight polarization in the optic lobes of Drosophila melanogaster.  <strong><em>Arthropod Struct Dev. <\/em><\/strong>Mar;61:101012.<\/li>\n\n\n\n<li class=\"\">Mathejczyk, T.F., <strong>Wernet, M.F.<\/strong> (2020). Modular assays for the quantitative study of visually guided navigation in both flying and walking flies. <strong><em>J Neurosci Methods<\/em><\/strong>. 340:108747. <\/li>\n\n\n\n<li class=\"\">Sancer, G., Kind, E., Uhlhorn, J., Volkmann, J., Hammacher, J., Pham, T., Plazaola-Sasieta, H., <strong>Wernet, M.F.<\/strong> (2019) Cellular and synaptic adaptations of neural circuits processing skylight polarization in the fly. <strong><em>J Comp Physiol A<\/em><\/strong> doi: 10.1007\/s00359-019-01389-3.<\/li>\n\n\n\n<li class=\"\">Mathejczyk, T.F., <strong>Wernet, M.F. <\/strong>(2019) Heading choices of flying Drosophila under changing angles of polarized light. <strong><em>Sci Rep<\/em><\/strong> 9(1):16773. doi: 10.1038\/s41598-019-53330-y.<\/li>\n\n\n\n<li class=\"\">Sancer, G., Kind, E., Plazaola-Sasieta, H., Balke, J., Pham, T., Hasan, A., M\u00fcnch, L.O., Courgeon, M., Mathejczyk, T.F., <strong>Wernet, M.F.<\/strong> (2019) Modality-Specific Circuits for Skylight Orientation in the Fly Visual System. <strong><em>Curr Biol<\/em><\/strong> 29(17):2812-2825.e4. doi: 10.1016\/j.cub.2019.07.020.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>RobustCircuit Project 3 Funding Period 2022-2026 Project. Updates on new 2026-2030 project to follow soon! From spatiotemporal restriction of imprecise synaptic partner choice to a robust representation of navigational information&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"nf_dc_page":"","footnotes":""},"class_list":["post-126","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Project 3 - RobustCircuit<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/robustcircuit.flygen.org\/?page_id=126\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Project 3 - RobustCircuit\" \/>\n<meta property=\"og:description\" content=\"RobustCircuit Project 3 Funding Period 2022-2026 Project. 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