Lobula Plate Tangential Cells in Drosophila melanogaster ; Response Properties, Synaptic Organization & Input Channels Maximilian Albert Jösch Krotki München 2009 2 Lobula Plate Tangential Cells in Drosophila melanogaster ; Response Properties, Synaptic Organization & Input Channels Dissertation Zur Erlangung des Doktorgrades der Naturwissenschaften (Dr.rer.nat.) der Fakultät für Biologie der Ludwig-Maximilians-Universität München Angefertigt am Max-Planck-Institüt für Neurobiologie, Abteilung „Neuronale Informationsverarbeitung‟ Vorgelegt von Maximilian Albert Jösch Krotki München 2009 3 Hiermit erkläre ich, daß ich die vorliegende Dissertation selbständig und ohne unerlaubte Hilfe angefertigt habe. Sämtliche Experimente wurden von mir selbst durchgeführt, außer wenn explizit auf Dritte verwiesen wird. Ich habe weder anderweitig versucht, eine Dissertation oder Teile einer Dissertation einzureichen bzw. einer Prüfungskommission vorzulegen, noch eine Doktorprüfung durchzuführen. München, den 01.10.2009 1. Gutachter: Prof. Dr. Alexander Borst 2. Gutachter: Prof. Dr. Rainer Uhl Tag der mündlichen Prüfung: 26. November 2009 4 Table of Contents Table of Contents .............................................................................................................................. 5 List of Figures ..................................................................................................................................... 8 1 Abstract ......................................................................................................................................... 11 2 Introduction ................................................................................................................................... 13 2.1 General remarks .................................................................................................................... 13 2.2 Visual course control in insects ............................................................................................... 14 2.3 The fly visual system .............................................................................................................. 16 2.3.1 The retina ......................................................................................................................... 16 2.3.2 Phototransduction ............................................................................................................. 17 2.3.3 The optic lobes ................................................................................................................. 19 2.3.4 Motion sensitive interneurons in the lobula plate of large fly species .................................. 22 2.4 The Reichardt detector ........................................................................................................... 25 2.4.1 Experimental evidence ...................................................................................................... 26 2.4.2 Biological correlates of the motion computation pathway. ................................................. 28 2.4.2.1 Motion detection in the retina ............................................................................... 28 2.4.2.2 Motion detection in the lamina .............................................................................. 29 2.4.2.3 Motion detection in the in the medulla and lobula ................................................ 30 2.4.2.4 Motion detection in the in the lobula plate ............................................................ 31 2.4.3 Motion computation in other organisms ............................................................................. 32 2.5 The genetic armory of Drosophila melanogaster .................................................................... 32 2.6 Project goals and achievements ............................................................................................. 35 3 Manuscript Nr.1 ...................................................................................................................... 39 Synaptic Organization of Lobula Plate Tangential Cells in Drosophila: GABA-receptors and chemical release sites. ........................................................................................................................................... 39 Abstract .............................................................................................................................................. 40 Introduction ....................................................................................................................................... 41 Materials and methods ...................................................................................................................... 45 Results ................................................................................................................................................ 48 The Gal4-3A expression pattern ................................................................................................... 48 Protocerebral projections of VS- and HS-cells express markers for output synapses .................... 50 MARCM analysis identifies protocerebral projections as sole expression sites of presynaptic markers in VS-cells ......................................................................................................................... 50 Dendritic tips and central projections of all VS-cells show evidence for inhibitory input synapses . 52 Dendritic tips and central projections of the HSE-cell show evidence for inhibitory input synapses 55 Indications for GABAergic input onto LPTCs ................................................................................... 56 Discussion .......................................................................................................................................... 58 Connectivity of VS- and HS-cells in the fly visual system ............................................................... 58 Genetic methods for the analysis of synaptic connectivity ............................................................. 59 Evidence for exclusively postsynaptic VS- and HS-cell dendrites in the lobula plate ..................... 60 Evidence for inhibitory input to VS- and HS-cell axon terminals in the protocerebrum .................. 62 Supplementary Material .................................................................................................................... 64 Acknowledgements ............................................................................................................................. 65 5 References .......................................................................................................................................... 65 4 Manuscript Nr.2 ............................................................................................................................ 71 Response Properties of Motion-Sensitive Visual Interneurons in the Lobula Plate of Drosophila melanogaster. ........................................................................................................................................... 71 Summary ............................................................................................................................................ 72 Results and Discussion ...................................................................................................................... 73 Whole Cell Patch Recordings Reveal Six Motion Sensitive Drosophila VS-cells (VS1-VS6). ........... 75 Receptive Field Organization and Evidence for a Drosophila VS-cell network. ............................. 76 Computational Structure of the Presynaptic Motion Detection Circuitry ......................................... 78 Experimental procedures ................................................................................................................... 84 Supplementary Material .................................................................................................................... 87 Supplementary Reference.............................................................................................................. 89 Acknowledgements ............................................................................................................................. 89 References .......................................................................................................................................... 90 5 Manuscript Nr. 3 ..................................................................................................................... 93 Synaptic Organization of Lobula Plate Tangential Cells in Drosophila: Dα7 Cholinergic Receptors. .. 93 Abstract .............................................................................................................................................. 94 Introduction ....................................................................................................................................... 95 Materials and Methods ...................................................................................................................... 98 Results .............................................................................................................................................. 101 Immunolabeling provides evidence for excitatory cholinergic input to the dendritic tips of VS and HS cells. ......................................................................................................................................