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Selected Works

Christopher Fang-Yen

Articles 1 - 12 of 12

Full-Text Articles in Neuroscience and Neurobiology

A Sleep State In Drosophila Larvae Required For Neural Stem Cell Proliferation, Milan Szuperak, Matthew A. Churgin, Christopher Fang-Yen, Kayser S. Matthew Feb 2018

A Sleep State In Drosophila Larvae Required For Neural Stem Cell Proliferation, Milan Szuperak, Matthew A. Churgin, Christopher Fang-Yen, Kayser S. Matthew

Christopher Fang-Yen

Sleep during development is involved in refining brain circuitry, but a role for sleep in the earliest periods of nervous system elaboration, when neurons are first being born, has not been explored. Here we identify a sleep state in Drosophila larvae that coincides with a major wave of neurogenesis. Mechanisms controlling larval sleep are partially distinct from adult sleep: octopamine, the Drosophila analog of mammalian norepinephrine, is the major arousal neuromodulator in larvae, but dopamine is not required. Using real-time behavioral monitoring in a closed-loop sleep deprivation system, we find that sleep loss in larvae impairs cell division of neural …

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Distributed Rhythm Generators Underlie Caenorhabditis Elegans Forward Locomotion, Anthony D. Fouad, Christopher Fang-Yen Dec 2017

Distributed Rhythm Generators Underlie Caenorhabditis Elegans Forward Locomotion, Anthony D. Fouad, Christopher Fang-Yen

Christopher Fang-Yen

Coordinated rhythmic movements are ubiquitous in animal behavior. In many organisms, chains of neural oscillators underlie the generation of these rhythms. In C. elegans, locomotor wave generation has been poorly understood; in particular, it is unclear where in the circuit rhythms are generated, and whether there exists more than one such generator. We used optogenetic and ablation experiments to probe the nature of rhythm generation in the locomotor circuit. We found that multiple sections of forward locomotor circuitry are capable of independently generating rhythms. By perturbing different components of the motor circuit, we localize the source of secondary rhythms …

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Antagonistic Serotonergic And Octopaminergic Neural Circuits Mediate Food-Dependent Locomotory Behavior In Caenorhabditis Elegans, Matthew A. Churgin, Richard J. Mccloskey, Emily Peters, Christopher Fang-Yen Dec 2016

Antagonistic Serotonergic And Octopaminergic Neural Circuits Mediate Food-Dependent Locomotory Behavior In Caenorhabditis Elegans, Matthew A. Churgin, Richard J. Mccloskey, Emily Peters, Christopher Fang-Yen

Christopher Fang-Yen

No abstract provided.

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Comparing Caenorhabditis Elegans Gentle And Harsh Touch Response Behavior Using A Multiplexed Hydraulic Microfluidic Device, Patrick D. Mcclanahan, Joyce Xu, Christopher Fang-Yen Dec 2016

Comparing Caenorhabditis Elegans Gentle And Harsh Touch Response Behavior Using A Multiplexed Hydraulic Microfluidic Device, Patrick D. Mcclanahan, Joyce Xu, Christopher Fang-Yen

Christopher Fang-Yen

The roundworm Caenorhabditis elegans is an important model system for understanding the genetics and physiology of touch. Classical assays for C. elegans touch, which involve manually touching the animal with a probe and observing its response, are limited by their low throughput and qualitative nature. We developed a microfluidic device in which several dozen animals are subject to spatially localized mechanical stimuli with variable amplitude. The device contains 64 sinusoidal channels through which worms crawl, and hydraulic valves that deliver touch stimuli to the worms. We used this assay to characterize the behavioral responses to gentle touch stimuli and the …

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Food Responsiveness Regulates Episodic Behavioral States In Caenorhabditis Elegans, Richard J. Mccloskey, Anthony D. Fouad, Matthew A. Churgin, Christopher Fang-Yen Dec 2016

Food Responsiveness Regulates Episodic Behavioral States In Caenorhabditis Elegans, Richard J. Mccloskey, Anthony D. Fouad, Matthew A. Churgin, Christopher Fang-Yen

Christopher Fang-Yen

Animals optimize sur- vival and reproduction in part through control of behavioral states, which depend on an organism’s internal and external environments. In the nematode Caenorhabditis elegans a variety of behavioral states have been described, including roaming, dwelling, quiescence, and episodic swimming. These states have been considered in isolation under varied experimental conditions, making it difficult to establish a unified picture of how they are regulated. Using long-term imaging, we examined C. elegans episodic behavioral states under varied mechanical and nutritional environments. We found that animals alternate between high-activity (active) and low-activity (sedentary) episodes in any mechanical environment, while the …

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Pharyngeal Pumping In Caenorhabditis Elegans Depends On Tonic And Phasic Signaling From The Nervous System, Nicholas Trojanowski, David M. Raizen, Christopher Fang-Yen Dec 2015

Pharyngeal Pumping In Caenorhabditis Elegans Depends On Tonic And Phasic Signaling From The Nervous System, Nicholas Trojanowski, David M. Raizen, Christopher Fang-Yen

Christopher Fang-Yen

Rhythmic movements are ubiquitous in animal locomotion, feeding, and circulatory systems. In some systems, the muscle itself generates rhythmic contractions. In others, rhythms are generated by the nervous system or by interactions between the nervous system and muscles. In
the nematode Caenorhabditis elegans, feeding occurs via rhythmic contractions (pumping) of the pharynx, a neuromuscular feeding organ. Here, we use pharmacology, optogenetics, genetics, and electrophysiology to investigate the roles of the nervous system and muscle in generating pharyngeal pumping. Hyperpolarization of the nervous system using a histamine-gated chloride channel abolishes pumping, and optogenetic stimulation of pharyngeal muscle in these animals causes …

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Distinct Mechanisms Underlie Quiescence During Two Caenorhabditis Elegans Sleep-Like States, Nicholas Trojanowski, Matthew D. Nelson, Steven Flavell, Christopher Fang-Yen, David M. Raizen Dec 2014

Distinct Mechanisms Underlie Quiescence During Two Caenorhabditis Elegans Sleep-Like States, Nicholas Trojanowski, Matthew D. Nelson, Steven Flavell, Christopher Fang-Yen, David M. Raizen

Christopher Fang-Yen

Electrophysiological recordings have enabled identification of physiologically distinct yet behaviorally similar states of mammalian sleep. In contrast, sleep in nonmammals has generally been identified behaviorally and therefore regarded as a physiologically uniform state characterized by quiescence of feeding and locomotion, reduced responsiveness, and rapid reversibility. The nematode Caenorhab- ditis elegans displays sleep-like quiescent behavior under two conditions: developmentally timed quiescence (DTQ) occurs during larval transitions, and stress-induced quiescence (SIQ) occurs in response to exposure to cellular stressors. Behaviorally, DTQ and SIQ appear identical. Here, we use optogenetic manipulations of neuronal and muscular activity, pharmacology, and genetic perturbations to uncover circuit …

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Neural And Genetic Degeneracy Underlies Caenorhabditis Elegans Feeding Behavior, Christopher Fang-Yen Dec 2013

Neural And Genetic Degeneracy Underlies Caenorhabditis Elegans Feeding Behavior, Christopher Fang-Yen

Christopher Fang-Yen

Neural and genetic degeneracy underlies Caenorhabditis elegans feeding behavior. J Neurophysiol 112: 951–961, 2014. First published May 28, 2014; doi:10.1152/jn.00150.2014.—Degenerate networks, in which structurally distinct elements can perform the same function or yield the same output, are ubiquitous in biology. Degeneracy contrib- utes to the robustness and adaptability of networks in varied environ- mental and evolutionary contexts. However, how degenerate neural networks regulate behavior in vivo is poorly understood, especially at the genetic level. Here, we identify degenerate neural and genetic mechanisms that underlie excitation of the pharynx (feeding organ) in the nematode Caenorhabditis elegans using cell-specific optogenetic excitation and …

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Optogenetic Manipulation Of Neural Activity In Freely Moving Caenorhabditis Elegans, Andrew Leifer, Christopher Fang-Yen, Marc Gershow, Mark Alkema, Aravinthan Samuel Apr 2013

Optogenetic Manipulation Of Neural Activity In Freely Moving Caenorhabditis Elegans, Andrew Leifer, Christopher Fang-Yen, Marc Gershow, Mark Alkema, Aravinthan Samuel

Christopher Fang-Yen

We present an optogenetic illumination system capable of real-time light delivery with high spatial resolution to specified targets in freely moving Caenorhabditis elegans. A tracking microscope records the motion of an unrestrained worm expressing channelrhodopsin-2 or halorhodopsin in specific cell types. Image processing software analyzes the worm's position in each video frame, rapidly estimates the locations of targeted cells and instructs a digital micromirror device to illuminate targeted cells with laser light of the appropriate wavelengths to stimulate or inhibit activity. Because each cell in an unrestrained worm is a rapidly moving target, our system operates at high speed ( …

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Proprioceptive Coupling Within Motor Neurons Drives C. Elegans Forward Locomotion, Q Wen, M Po, S Chen, X Liu, M Gershow, A Leifer, V Butler, Christopher Fang-Yen, T Kawano, W R. Schafer, G Whitesides, M Wyart, D Chklovskii, M Zhen, A Samuel Dec 2011

Proprioceptive Coupling Within Motor Neurons Drives C. Elegans Forward Locomotion, Q Wen, M Po, S Chen, X Liu, M Gershow, A Leifer, V Butler, Christopher Fang-Yen, T Kawano, W R. Schafer, G Whitesides, M Wyart, D Chklovskii, M Zhen, A Samuel

Christopher Fang-Yen

No abstract provided.

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Functional Organization Of A Neural Network For Aversive Olfactory Learning In Caenorhabditis Elegans, H Ha, M Hendricks, Y Shen, C V. Gabel, Christopher Fang-Yen, Y Qin, D Colon-Ramos, K Shen, A D.T. Samuel Dec 2009

Functional Organization Of A Neural Network For Aversive Olfactory Learning In Caenorhabditis Elegans, H Ha, M Hendricks, Y Shen, C V. Gabel, Christopher Fang-Yen, Y Qin, D Colon-Ramos, K Shen, A D.T. Samuel

Christopher Fang-Yen

No abstract provided.

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Navigational Decision-Making In Drosophila Thermotaxis, L Luo, M Gershow, M Rosenzweig, K Kang, Christopher Fang-Yen, P Garrity, A D T Samuel Dec 2009

Navigational Decision-Making In Drosophila Thermotaxis, L Luo, M Gershow, M Rosenzweig, K Kang, Christopher Fang-Yen, P Garrity, A D T Samuel

Christopher Fang-Yen

No abstract provided.

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