Single Neuron Contributions to Sensory Behaviors in Drosophila melanogaster Público

Abstract

Sensory systems are key to understanding how neuron circuity translates environmental stimuli into behavioral output. Neurons transform information about our surroundings into electrical signals. By working in coordination, neurons relay information about our world and allow us to perceive and react appropriately to it. However, the rules by which sensory input is interpreted by neuronal circuitry is poorly understood.

My graduate work contributes to understanding sensory systems by mapping functions to sensory neurons. Mapping includes answering the following: Which sensory neurons contribute to a particular behavior? What features of the stimulus are extracted by a specific neuron? How does a single neuron incorporate with others in a circuit to produce a behavior?

I have used Drosophila melanogaster, the fruit fly, to better understand how single sensory neurons function and communicate. Fly brains have only around 100,000 neurons while human brains have around 100 billion neurons. Yet, fly sensory systems operate on the same basic principles as our own.1 Flies are sufficiently complex to produce sophisticated behaviors but are sufficiently simple that an understanding of the causal neuronal mechanisms is within our reach. 2 Drosophila provides a simpler, more tractable, and more genetically malleable system to study the broadly-relevant principles by which sensory information is encoded by neurons.

Somehow through the structure of receptors and activity of neurons, Drosophila sensory systems carry out remarkably complex tasks. For example, flies use an olfactory system to discriminate among innumerable diverse chemicals. The olfactory system copes with the “noise” of irrelevant chemicals and distinguishes the relative quantity and quality of odorants. Ultimately, the animal produces a behavioral response to this information such as moving towards mates or avoiding predators. The visual system is likewise extraordinary. From the simple act of photons hitting a receptor, the intricate visual circuity encodes visual features such as contrast, speed, intensity, wavelength, complexity, direction, distance, texture, polarization etc. Flies use this information for myriad behaviors including navigation, breeding, feeding, and predator avoidance.

In the next three chapters, I will describe specific projects in the olfactory and visual sensory systems that aim to illuminate neuronal mechanisms of sensation and behavior.

Table of Contents

Thesis Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chapter 1: A GAL80 collection to nullify transgenes in Drosophila olfactory sensory

neurons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Supplemental Figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Auxiliary Projects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Materials and Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Chapter 2: A Screen to Identify Neuronal Candidates of Color and Translational

Motion Pathways in Drosophila. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Supplemental Figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75

Materials and Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78

Chapter 3: A Novel Neuronal Pathway to Encode Regressive Motion and Regulate

Forward Walking Speed in Drosophila. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Supplemental Figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113

Materials and Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119

Thesis Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

List of Figures

Chapter 1

Figure 1: Olfactory Sensory Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 2: Advantages of using a GAL80 over a null mutation. . . . . . . . . . . . . . . . 8

Figure 3: Or-GAL80 reagents eliminate GAL4 activity . . . . . . . . . . . . . . . . . . . .12

Figure 4: ORN responses to CO2 in a Single Sensillum Recordings (SSR) . . . . .13

Figure 5: Use of Or-GAL80 reagents in a behavioral experiment. . . . . . . . . . . . .14

Figure S1: GAL80 reduces GAL4 expression in larvae . . . . . . . . . . . . . . . . . . . .19

Figure S2: DSCP required in destination vector

for effective GAL80 expression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure S3: GAL80 Specificity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Table S1: PCR Primers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table S2: Sequencing Primers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Figure A1: Peripheral Neuronal Pairings in a Behavioral Assay. . . . . . . . . . . . . 25

Figure A2: Isolated OSNs and Volumetric Plasticity. . . . . . . . . . . . . . . . . . . . . . 28

Figure A3: Olfactory System with only BmOR1 OSNs. . . . . . . . . . . . . . . . . . . . 32

Figure A4: Example of a behavior using the fly described in Figure A3. . . . . . . 34

Chapter 2

Figure 1: Anatomy of the Visual System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

Explanatory Insert: A Model for Motion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Figure 2: High-Throughput Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Figure 3: Behavior/Anatomy Screen Schematic. . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 1: Summary of Screen Phase I. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Figure 4: Results of Screen, Phase I. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Figure 5: Sample Web Page. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Figure 6: Brain Anatomy Maps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62

Figure 7: Screen Phase II. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63

Table 2: Summary of Screen Phase II. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Figure 8: Expected Hits from screen Phase II. . . . . . . . . . . . . . . . . . . . . . . . . . . .65

Figure 9: Novel Correlates of Motion Vision. . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Figure S1: Single Fly Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure S2: Adding Kir2.1 to Screen Phase II. . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure S3: Two models for “Against” Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . 76

Figure S4: Hits from screen with treadmill assay. . . . . . . . . . . . . . . . . . . . . . . . . 77

Chapter 3

Figure 1: Translation and Rotation Optic Flow. . . . . . . . . . . . . . . . . . . . . . . . . . .87

Figure 2: LPC1 Anatomy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89

Figure 3: LPC1 Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Figure 4: Control responses to translational and rotational stimuli. . . . . . . . . . . 93

Figure 5: LPC1 detects Regressive Motion and Modulates Walking Speed. . . . 95

Figure 6: LPC1 Imaging and Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98

Figure 7: LPC1 Activation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

Figure 8: Functional Connectivity of LPC1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .107

Figure S1: LPC1 with Different Effectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113

Figure S2: LPC1 Split Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Figure S3: Speed Tuning of LPC1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115

Figure S4: TEM Tracing of LPC1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116

Figure S5: Contrast Tuning of Walking Flies. . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Figure S6: Contrast Tuning of LPC1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118

About this Dissertation

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School	Laney Graduate School
Department	Biological and Biomedical Sciences
Subfield / Discipline	Genetics and Molecular Biology
Degree	Ph.D.
Submission	Dissertation
Language	English
Research Field	Biology, Neuroscience Biology, Genetics
Palavra-chave	Behavior Sensory Vision Olfaction Drosophila GAL80
Committee Chair / Thesis Advisor	Matsumura, Ichiro, Emory University Reiser, Michael, HHMI/Janelia Farm
Committee Members	Moberg, Kenneth, Emory University Hall, Randy, Emory University Escayg, Andrew, Emory University

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