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Yang HH, Brezovec LE, Capdevila LS, Vanderbeck QX, Adachi A, Mann RS, Wilson RI. Fine-grained descending control of steering in walking Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.15.562426. [PMID: 37904997 PMCID: PMC10614758 DOI: 10.1101/2023.10.15.562426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Locomotion involves rhythmic limb movement patterns that originate in circuits outside the brain. Purposeful locomotion requires descending commands from the brain, but we do not understand how these commands are structured. Here we investigate this issue, focusing on the control of steering in walking Drosophila. First, we describe different limb "gestures" associated with different steering maneuvers. Next, we identify a set of descending neurons whose activity predicts steering. Focusing on two descending cell types downstream from distinct brain networks, we show that they evoke specific limb gestures: one lengthens strides on the outside of a turn, while the other attenuates strides on the inside of a turn. Notably, a single descending neuron can have opposite effects during different locomotor rhythm phases, and we identify networks positioned to implement this phase-specific gating. Together, our results show how purposeful locomotion emerges from brain cells that drive specific, coordinated modulations of low-level patterns.
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Affiliation(s)
- Helen H. Yang
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115 USA
| | - Luke E. Brezovec
- Department of Neurobiology, Stanford University, Stanford, CA 94305 USA
| | | | | | - Atsuko Adachi
- Department of Biochemistry and Molecular Biophysics, Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027 USA
| | - Richard S. Mann
- Department of Biochemistry and Molecular Biophysics, Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027 USA
| | - Rachel I. Wilson
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115 USA
- Lead contact
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2
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Cruz TL, Chiappe ME. Multilevel visuomotor control of locomotion in Drosophila. Curr Opin Neurobiol 2023; 82:102774. [PMID: 37651855 DOI: 10.1016/j.conb.2023.102774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 07/26/2023] [Accepted: 08/01/2023] [Indexed: 09/02/2023]
Abstract
Vision is critical for the control of locomotion, but the underlying neural mechanisms by which visuomotor circuits contribute to the movement of the body through space are yet not well understood. Locomotion engages multiple control systems, forming distinct interacting "control levels" driven by the activity of distributed and overlapping circuits. Therefore, a comprehensive understanding of the mechanisms underlying locomotion control requires the consideration of all control levels and their necessary coordination. Due to their small size and the wide availability of experimental tools, Drosophila has become an important model system to study this coordination. Traditionally, insect locomotion has been divided into studying either the biomechanics and local control of limbs, or navigation and course control. However, recent developments in tracking techniques, and physiological and genetic tools in Drosophila have prompted researchers to examine multilevel control coordination in flight and walking.
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Affiliation(s)
- Tomás L Cruz
- Champalimaud Research, Champalimaud Centre for the Unknown, 1400-038 Lisbon, Portugal
| | - M Eugenia Chiappe
- Champalimaud Research, Champalimaud Centre for the Unknown, 1400-038 Lisbon, Portugal.
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3
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Goldammer J, Büschges A, Dürr V. Descending interneurons of the stick insect connecting brain neuropiles with the prothoracic ganglion. PLoS One 2023; 18:e0290359. [PMID: 37651417 PMCID: PMC10470933 DOI: 10.1371/journal.pone.0290359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 08/04/2023] [Indexed: 09/02/2023] Open
Abstract
Stick insects respond to visual or tactile stimuli with whole-body turning or directed reach-to-grasp movements. Such sensory-induced turning and reaching behaviour requires interneurons to convey information from sensory neuropils of the head ganglia to motor neuropils of the thoracic ganglia. To date, descending interneurons are largely unknown in stick insects. In particular, it is unclear whether the special role of the front legs in sensory-induced turning and reaching has a neuroanatomical correlate in terms of descending interneuron numbers. Here, we describe the population of descending interneurons with somata in the brain or gnathal ganglion in the stick insect Carausius morosus, providing a first map of soma cluster counts and locations. By comparison of interneuron populations with projections to the pro- and mesothoracic ganglia, we then estimate the fraction of descending interneurons that terminate in the prothoracic ganglion. With regard to short-latency, touch-mediated reach-to-grasp movements, we also locate likely sites of synaptic interactions between antennal proprioceptive afferents to the deutocerebrum and gnathal ganglion with descending or ascending interneuron fibres. To this end, we combine fluorescent dye stainings of thoracic connectives with stainings of antennal hair field sensilla. Backfills of neck connectives revealed up to 410 descending interneuron somata (brain: 205 in 19 clusters; gnathal ganglion: 205). In comparison, backfills of the prothorax-mesothorax connectives stained only up to 173 somata (brain: 83 in 16 clusters; gnathal ganglion: 90), suggesting that up to 60% of all descending interneurons may terminate in the prothoracic ganglion (estimated upper bound). Double stainings of connectives and antennal hair field sensilla revealed that ascending or descending fibres arborise in close proximity of afferent terminals in the deutocerebrum and in the middle part of the gnathal ganglia. We conclude that two cephalothoracic pathways may convey cues about antennal movement and pointing direction to thoracic motor centres via two synapses only.
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Affiliation(s)
- Jens Goldammer
- Department of Animal Physiology and Neurobiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Cologne, Germany
| | - Ansgar Büschges
- Department of Animal Physiology and Neurobiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Cologne, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Bielefeld University, Bielefeld, Germany
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4
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Rana A, Adams ME, Libersat F. Parasitoid wasp venom re-programs host behavior through downmodulation of brain central complex activity and motor output. J Exp Biol 2023; 226:286758. [PMID: 36700409 PMCID: PMC10088415 DOI: 10.1242/jeb.245252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 01/12/2023] [Indexed: 01/27/2023]
Abstract
The parasitoid wasp Ampulex compressa hunts down its host, the American cockroach (Periplaneta americana), and envenomates its brain to make it a behaviorally compliant food supply for its offspring. The primary target of the wasp sting is a locomotory command center called the central complex (CX). In the present study, we employ, for the first time, chronic recordings of patterned cockroach CX activity in real time as the brain is infused with wasp venom. CX envenomation is followed by sequential changes in the pattern of neuronal firing that can be divided into three distinct temporal phases during the 2 h interval after venom injection: (1) reduction in neuronal activity for roughly 10 min immediately after venom injection; (2) rebound of activity lasting up to 25 min; (3) reduction of ongoing activity for up to 2 h. Long-term reduction of CX activity after venom injection is accompanied by decreased activity of both descending interneurons projecting to thoracic locomotory circuitry (DINs) and motor output. Thus, in this study, we provide a plausible chain of events starting in the CX that leads to decreased host locomotion following brain envenomation. We propose that these events account for the onset and maintenance of the prolonged hypokinetic state observed in stung cockroaches.
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Affiliation(s)
- Amit Rana
- Department of Life Sciences and Zlotowski Center for Neurosciences, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Michael E Adams
- Departments of Entomology and Molecular, Cell, and Systems Biology, University of California, Riverside, CA 92521, USA
| | - Frederic Libersat
- Department of Life Sciences and Zlotowski Center for Neurosciences, Ben Gurion University of the Negev, Beer Sheva, Israel
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5
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Nordio S, Kaiser M, Adams ME, Libersat F. Parasitoid wasp venom manipulates host innate behavior via subtype-specific dopamine receptor activation. J Exp Biol 2022; 225:274808. [PMID: 35320357 PMCID: PMC8996814 DOI: 10.1242/jeb.243674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 01/27/2022] [Indexed: 11/29/2022]
Abstract
The subjugation strategy employed by the jewel wasp is unique in that it manipulates the behavior of its host, the American cockroach, rather than inducing outright paralysis. Upon envenomation directly into the central complex (CX), a command center in the brain for motor behavior, the stung cockroach initially engages in intense grooming behavior, then falls into a lethargic sleep-like state referred to as hypokinesia. Behavioral changes evoked by the sting are due at least in part to the presence of the neurotransmitter dopamine in the venom. In insects, dopamine receptors are classified as two families, the D1-like and the D2-like receptors. However, specific roles played by dopamine receptor subtypes in venom-induced behavioral manipulation by the jewel wasp remain largely unknown. In the present study, we used a pharmacological approach to investigate roles of D1-like and D2-like receptors in behaviors exhibited by stung cockroaches, focusing on grooming. Specifically, we assessed behavioral outcomes of focal CX injections of dopamine receptor agonists and antagonists. Both specific and non-specific compounds were used. Our results strongly implicate D1-like dopamine receptors in venom-induced grooming. Regarding induction of hypokinesia, our findings demonstrate that dopamine signaling is necessary for induction of long-lasting hypokinesia caused by brain envenomation. Highlighted Article: Subtype-specific dopamine receptors are involved in the manipulation of host behavior by the parasitoid jewel wasp.
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Affiliation(s)
- Stefania Nordio
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel
| | - Maayan Kaiser
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel
| | - Michael E Adams
- Department of Entomology, University of California, Riverside, CA 92521, USA.,Department of Molecular, Cell, and Systems Biology, University of California, Riverside, CA 92521, USA
| | - Frederic Libersat
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel
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6
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Naniwa K, Aonuma H. Descending and Ascending Signals That Maintain Rhythmic Walking Pattern in Crickets. Front Robot AI 2021; 8:625094. [PMID: 33855051 PMCID: PMC8039156 DOI: 10.3389/frobt.2021.625094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/01/2021] [Indexed: 12/04/2022] Open
Abstract
The cricket is one of the model animals used to investigate the neuronal mechanisms underlying adaptive locomotion. An intact cricket walks mostly with a tripod gait, similar to other insects. The motor control center of the leg movements is located in the thoracic ganglia. In this study, we investigated the walking gait patterns of the crickets whose ventral nerve cords were surgically cut to gain an understanding of how the descending signals from the head ganglia and ascending signals from the abdominal nervous system into the thoracic ganglia mediate the initiation and coordination of the walking gait pattern. Crickets whose paired connectives between the brain and subesophageal ganglion (SEG) (circumesophageal connectives) were cut exhibited a tripod gait pattern. However, when one side of the circumesophageal connectives was cut, the crickets continued to turn in the opposite direction to the connective cut. Crickets whose paired connectives between the SEG and prothoracic ganglion were cut did not walk, whereas the crickets exhibited an ordinal tripod gait pattern when one side of the connectives was intact. Crickets whose paired connectives between the metathoracic ganglion and abdominal ganglia were cut initiated walking, although the gait was not a coordinated tripod pattern, whereas the crickets exhibited a tripod gait when one side of the connectives was intact. These results suggest that the brain plays an inhibitory role in initiating leg movements and that both the descending signals from the head ganglia and the ascending signals from the abdominal nervous system are important in initiating and coordinating insect walking gait patterns.
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Affiliation(s)
- Keisuke Naniwa
- Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan
| | - Hitoshi Aonuma
- Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan
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Emanuel S, Kaiser M, Pflueger HJ, Libersat F. On the Role of the Head Ganglia in Posture and Walking in Insects. Front Physiol 2020; 11:135. [PMID: 32153430 PMCID: PMC7047666 DOI: 10.3389/fphys.2020.00135] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 02/07/2020] [Indexed: 12/04/2022] Open
Abstract
In insects, locomotion is the result of rhythm generating thoracic circuits and their modulation by sensory reflexes and by inputs from the two head ganglia, the cerebral and the gnathal ganglia (GNG), which act as higher order neuronal centers playing different functions in the initiation, goal-direction, and maintenance of movement. Current knowledge on the various roles of major neuropiles of the cerebral ganglia (CRG), such as mushroom bodies (MB) and the central complex (CX), in particular, are discussed as well as the role of the GNG. Thoracic and head ganglia circuitries are connected by ascending and descending neurons. While less is known about the ascending neurons, recent studies in large insects and Drosophila have begun to unravel the identity of descending neurons and their appropriate roles in posture and locomotion. Descending inputs from the head ganglia are most important in initiating and modulating thoracic central pattern generating circuitries to achieve goal directed locomotion. In addition, the review will also deal with some known monoaminergic descending neurons which affect the motor circuits involved in posture and locomotion. In conclusion, we will present a few issues that have, until today, been little explored. For example, how and which descending neurons are selected to engage a specific motor behavior and how feedback from thoracic circuitry modulate the head ganglia circuitries. The review will discuss results from large insects, mainly locusts, crickets, and stick insects but will mostly focus on cockroaches and the fruit fly, Drosophila.
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Affiliation(s)
- Stav Emanuel
- Department of Life Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Maayan Kaiser
- Department of Life Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Hans-Joachim Pflueger
- Fachbereich Biologie Chemie Pharmazie, Institut für Biologie, Neurobiologie, Freie Universität Berlin, Berlin, Germany
| | - Frederic Libersat
- Department of Life Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beersheba, Israel
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Mustard JA, Jones L, Wright GA. GABA signaling affects motor function in the honey bee. JOURNAL OF INSECT PHYSIOLOGY 2020; 120:103989. [PMID: 31805284 DOI: 10.1016/j.jinsphys.2019.103989] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/26/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
GABA is the most common inhibitory neurotransmitter in both vertebrate and invertebrate nervous systems. In insects, inhibition plays important roles at the neuromuscular junction, in the regulation of central pattern generators, and in the modulation of information in higher brain processing centers. Additionally, increasing our understanding of the functions of GABA is important since GABAA receptors are the targets of several classes of pesticides. To investigate the role of GABA in motor function, honey bee foragers were injected with GABA or with agonists or antagonists specific for either GABAA or GABAB receptors. Compounds that activated either type of GABA receptor decreased activity levels. Bees injected with the GABAA receptor antagonist picrotoxin lost the ability to right themselves, whereas blockade of GABAB receptors led to increases in grooming. Injection with antagonists of either GABAA or GABAB receptors resulted in an increase in extended wing behavior, during which bees kept their wings out at right angles to their body rather than folded along their back. These data suggest that the GABA receptor types play distinct roles in behavior and that GABA may affect behavior at several different levels.
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Affiliation(s)
- Julie A Mustard
- Department of Biology, University of Texas Rio Grande Valley, Brownsville, TX 78520, USA.
| | - Lisa Jones
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Geraldine A Wright
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom; Department of Zoology, University of Oxford, Oxford OX1 3SZ, United Kingdom
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9
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Stolz T, Diesner M, Neupert S, Hess ME, Delgado-Betancourt E, Pflüger HJ, Schmidt J. Descending octopaminergic neurons modulate sensory-evoked activity of thoracic motor neurons in stick insects. J Neurophysiol 2019; 122:2388-2413. [DOI: 10.1152/jn.00196.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neuromodulatory neurons located in the brain can influence activity in locomotor networks residing in the spinal cord or ventral nerve cords of invertebrates. How inputs to and outputs of neuromodulatory descending neurons affect walking activity is largely unknown. With the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and immunohistochemistry, we show that a population of dorsal unpaired median (DUM) neurons descending from the gnathal ganglion to thoracic ganglia of the stick insect Carausius morosus contains the neuromodulatory amine octopamine. These neurons receive excitatory input coupled to the legs’ stance phases during treadmill walking. Inputs did not result from connections with thoracic central pattern-generating networks, but, instead, most are derived from leg load sensors. In excitatory and inhibitory retractor coxae motor neurons, spike activity in the descending DUM (desDUM) neurons increased depolarizing reflexlike responses to stimulation of leg load sensors. In these motor neurons, descending octopaminergic neurons apparently functioned as components of a positive feedback network mainly driven by load-detecting sense organs. Reflexlike responses in excitatory extensor tibiae motor neurons evoked by stimulations of a femur-tibia movement sensor either are increased or decreased or were not affected by the activity of the descending neurons, indicating different functions of desDUM neurons. The increase in motor neuron activity is often accompanied by a reflex reversal, which is characteristic for actively moving animals. Our findings indicate that some descending octopaminergic neurons can facilitate motor activity during walking and support a sensory-motor state necessary for active leg movements. NEW & NOTEWORTHY We investigated the role of descending octopaminergic neurons in the gnathal ganglion of stick insects. The neurons become active during walking, mainly triggered by input from load sensors in the legs rather than pattern-generating networks. This report provides novel evidence that octopamine released by descending neurons on stimulation of leg sense organs contributes to the modulation of leg sensory-evoked activity in a leg motor control system.
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Affiliation(s)
- Thomas Stolz
- Departments of Biology and Animal Physiology, University of Cologne, Cologne, Germany
| | - Max Diesner
- Department of Biology, Institute of Zoology, University of Cologne, Cologne, Germany
| | - Susanne Neupert
- Department of Biology, Institute of Zoology, University of Cologne, Cologne, Germany
| | - Martin E. Hess
- Departments of Biology and Animal Physiology, University of Cologne, Cologne, Germany
| | | | - Hans-Joachim Pflüger
- Institute für Biologie und Neurobiologie, Freie Universität Berlin, Berlin, Germany
| | - Joachim Schmidt
- Departments of Biology and Animal Physiology, University of Cologne, Cologne, Germany
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10
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Emanuel S, Libersat F. Nociceptive Pathway in the Cockroach Periplaneta americana. Front Physiol 2019; 10:1100. [PMID: 31496959 PMCID: PMC6712093 DOI: 10.3389/fphys.2019.01100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/08/2019] [Indexed: 12/31/2022] Open
Abstract
Detecting and avoiding environmental threats such as those with a potential for injury is of crucial importance for an animal’s survival. In this work, we examine the nociceptive pathway in an insect, the cockroach Periplaneta americana, from detection of noxious stimuli to nocifensive behavior. We show that noxious stimuli applied to the cuticle of cockroaches evoke responses in sensory axons that are distinct from tactile sensory axons in the sensory afferent nerve. We also reveal differences in the evoked response of post-synaptic projection interneurons in the nerve cord to tactile versus noxious stimuli. Noxious stimuli are encoded in the cockroach nerve cord by fibers of diameter different from that of tactile and wind sensitive fibers with a slower conduction velocity of 2–3 m/s. Furthermore, recording from the neck-connectives show that the nociceptive information reaches the head ganglia. Removing the head ganglia results in a drastic decrease in the nocifensive response indicating that the head ganglia and the nerve cord are both involved in processing noxious stimuli.
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Affiliation(s)
- Stav Emanuel
- Department of Life Sciences and Zlotowski Center for Neurosciences, Ben Gurion University, Beer Sheva, Israel
| | - Frederic Libersat
- Department of Life Sciences and Zlotowski Center for Neurosciences, Ben Gurion University, Beer Sheva, Israel
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11
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Kaiser M, Arvidson R, Zarivach R, Adams ME, Libersat F. Molecular cross-talk in a unique parasitoid manipulation strategy. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 106:64-78. [PMID: 30508629 DOI: 10.1016/j.ibmb.2018.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/18/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
Envenomation of cockroach cerebral ganglia by the parasitoid Jewel wasp, Ampulex compressa, induces specific, long-lasting behavioural changes. We hypothesized that this prolonged action results from venom-induced changes in brain neurochemistry. Here, we address this issue by first identifying molecular targets of the venom, i.e., proteins to which venom components bind and interact with to mediate altered behaviour. Our results show that venom components bind to synaptic proteins and likely interfere with both pre- and postsynaptic processes. Since behavioural changes induced by the sting are long-lasting and reversible, we hypothesized further that long-term effects of the venom must be mediated by up or down regulation of cerebral ganglia proteins. We therefore characterize changes in cerebral ganglia protein abundance of stung cockroaches at different time points after the sting by quantitative mass spectrometry. Our findings indicate that numerous proteins are differentially expressed in cerebral ganglia of stung cockroaches, many of which are involved in signal transduction, such as the Rho GTPase pathway, which is implicated in synaptic plasticity. Altogether, our data suggest that the Jewel wasp commandeers cockroach behaviour through molecular cross-talk between venom components and molecular targets in the cockroach central nervous system, leading to broad-based alteration of synaptic efficacy and behavioural changes that promote successful development of wasp progeny.
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Affiliation(s)
- Maayan Kaiser
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva, 84105, Israel; Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva, 84105, Israel
| | - Ryan Arvidson
- Graduate Program in Biochemistry and Molecular Biology, University of California, Riverside, CA, 92521, USA; Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Raz Zarivach
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva, 84105, Israel
| | - Michael E Adams
- Graduate Program in Biochemistry and Molecular Biology, University of California, Riverside, CA, 92521, USA; Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA; Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Frederic Libersat
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva, 84105, Israel; Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva, 84105, Israel.
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12
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Reches E, Knebel D, Rillich J, Ayali A, Barzel B. The Metastability of the Double-Tripod Gait in Locust Locomotion. iScience 2019; 12:53-65. [PMID: 30677739 PMCID: PMC6352547 DOI: 10.1016/j.isci.2019.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 11/27/2018] [Accepted: 01/02/2019] [Indexed: 01/13/2023] Open
Abstract
Insect locomotion represents a fundamental example of neuronal oscillating circuits generating different motor patterns or gaits by controlling their phase coordination. Walking gaits are assumed to represent stable states of the system, often modeled as coupled oscillators. This view is challenged, however, by recent experimental observations, in which in vitro locust preparations consistently converged to synchronous rhythms (all legs oscillating as one), a locomotive pattern never seen in vivo. To reconcile this inconsistency, we developed a modeling framework to capture the trade-off between the two competing mechanisms: the endogenous neuronal circuitry, expressed in vitro, and the feedback mechanisms from sensory and descending inputs, active only in vivo. We show that the ubiquitously observed double-tripod walking gait emerges precisely from this balance. The outcome is a short-lived meta-stable double-tripod gait, which transitions and alternates with stable idling, thus recovering the observed intermittent bouts of locomotion, typical of many insects' locomotion behavior. Isolated in vitro locust preparations indicate that idling is a stable fictive gait This is in contrast to the dominant in vivo locomotive pattern (i.e., double tripod) Hence functional locomotion behavior is dependent on descending and sensory inputs The presented model generates intermittent double-tripod bouts as seen empirically
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Affiliation(s)
- Eran Reches
- Department of Mathematics, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Daniel Knebel
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel; Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Jan Rillich
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Amir Ayali
- School of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel; Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv 69978, Israel.
| | - Baruch Barzel
- Department of Mathematics, Bar-Ilan University, Ramat-Gan 52900, Israel.
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Knebel D, Rillich J, Nadler L, Pflüger HJ, Ayali A. The functional connectivity between the locust leg pattern generators and the subesophageal ganglion higher motor center. Neurosci Lett 2018; 692:77-82. [PMID: 30391322 DOI: 10.1016/j.neulet.2018.10.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 10/28/2018] [Accepted: 10/30/2018] [Indexed: 01/07/2023]
Abstract
Higher motor centers and central pattern generators (CPGs) interact in the control of coordinated leg movements during locomotion throughout the animal kingdom. The subesophageal ganglion (SEG) is one of the insect head ganglia reported to have a role in the control of walking behavior. Here we explored the functional relations between the SEG and the thoracic leg CPGs in the desert locust. Backfill staining revealed about 300 SEG descending interneurons (DINs) altogether. Recordings from an in-vitro isolated chain of thoracic ganglia, with intact or severed connections to the SEG, during pharmacological activation were used to determine how the SEG affects the centrally generated motor output to the legs. The SEG was demonstrated to both activate leg CPGs and synchronize their bilateral activity. The role of the SEG in insect locomotion is discussed in light of these findings.
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Affiliation(s)
- Daniel Knebel
- School of Zoology, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Jan Rillich
- School of Zoology, Tel Aviv University, Tel Aviv, Israel; Institute for Biology, University of Leipzig, Leipzig, Germany
| | - Leonard Nadler
- Institut für Neurobiologie, Freie Unversität Berlin, Berlin, Germany
| | | | - Amir Ayali
- School of Zoology, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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14
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Knebel D, Assaf Y, Ayali A. The use of MEMRI for monitoring central nervous system activity during intact insect walking. JOURNAL OF INSECT PHYSIOLOGY 2018; 108:48-53. [PMID: 29758239 DOI: 10.1016/j.jinsphys.2018.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/10/2018] [Accepted: 05/11/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Monitoring neuronal activity in the intact behaving animal is most desired in neuroethological research, yet it is rarely straightforward or even feasible. Here we present the use of manganese enhanced magnetic resonance imaging (MEMRI), a technique allowing monitoring the activity of an animal's nervous system during specific behavioral patterns. Using MEMRI we were able to show activity in different ganglia of the central nervous system of intact locusts during walking. RESULTS We injected two groups of locusts with manganese, which serves as a magnetic contrast agent. One group was forced to walk on a treadmill for two hours, while the other was immobilized and served as a control. Subsequently, all animals were scanned in a T1 MRI protocol, and the accumulation of manganese in the neuronal tissues that were active during walking was demonstrated by comparing the scans of the two groups. Two neuronal sites showed significantly higher T1 signal in the walking locusts compared to the immobilized ones: the prothoracic ganglion, which locally controls the front legs, and the subesophageal ganglion, a head ganglion which takes part in initiation and maintenance of walking. CONCLUSION MEMRI is a potent, non-invasive technique for monitoring neuronal activity in intact locusts, and arthropods in general. Specifically, it provides a promising way for revealing the role of central and high-order neuronal structures in motor behaviors such as walking.
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Affiliation(s)
- Daniel Knebel
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Yaniv Assaf
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Amir Ayali
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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15
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Namiki S, Dickinson MH, Wong AM, Korff W, Card GM. The functional organization of descending sensory-motor pathways in Drosophila. eLife 2018; 7:e34272. [PMID: 29943730 PMCID: PMC6019073 DOI: 10.7554/elife.34272] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/09/2018] [Indexed: 12/12/2022] Open
Abstract
In most animals, the brain controls the body via a set of descending neurons (DNs) that traverse the neck. DN activity activates, maintains or modulates locomotion and other behaviors. Individual DNs have been well-studied in species from insects to primates, but little is known about overall connectivity patterns across the DN population. We systematically investigated DN anatomy in Drosophila melanogaster and created over 100 transgenic lines targeting individual cell types. We identified roughly half of all Drosophila DNs and comprehensively map connectivity between sensory and motor neuropils in the brain and nerve cord, respectively. We find the nerve cord is a layered system of neuropils reflecting the fly's capability for two largely independent means of locomotion -- walking and flight -- using distinct sets of appendages. Our results reveal the basic functional map of descending pathways in flies and provide tools for systematic interrogation of neural circuits.
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Affiliation(s)
- Shigehiro Namiki
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Michael H Dickinson
- Division of Biology and BioengineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Allan M Wong
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Wyatt Korff
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gwyneth M Card
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
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16
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Knebel D, Wörner J, Rillich J, Nadler L, Ayali A, Couzin-Fuchs E. The subesophageal ganglion modulates locust inter-leg sensory-motor interactions via contralateral pathways. JOURNAL OF INSECT PHYSIOLOGY 2018; 107:116-124. [PMID: 29577874 DOI: 10.1016/j.jinsphys.2018.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 06/08/2023]
Abstract
The neural control of insect locomotion is distributed among various body segments. Local pattern-generating circuits at the thoracic ganglia interact with incoming sensory signals and central descending commands from the head ganglia. The evidence from different insect preparations suggests that the subesophageal ganglion (SEG) may play an important role in locomotion-related tasks. In a previous study, we demonstrated that the locust SEG modulates the coupling pattern between segmental leg CPGs in the absence of sensory feedback. Here, we investigated its role in processing and transmitting sensory information to the leg motor centers and mapped the major related neural pathways. Specifically, the intra- and inter-segmental transfer of leg-feedback were studied by simultaneously monitoring motor responses and descending signals from the SEG. Our findings reveal a crucial role of the SEG in the transfer of intersegmental, but not intrasegmental, signals. Additional lesion experiments, in which the intersegmental connectives were cut at different locations, together with double nerve staining, indicated that sensory signals are mainly transferred to the SEG via the connective contralateral to the stimulated leg. We therefore suggest that, similar to data reported for vertebrates, insect leg sensory-motor loops comprise contralateral ascending pathways to the head and ipsilateral descending ones.
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Affiliation(s)
- Daniel Knebel
- School of Zoology, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Johanna Wörner
- Department of Biology, Universität Konstanz, Konstanz, Germany
| | - Jan Rillich
- School of Zoology, Tel Aviv University, Tel Aviv, Israel; Institute for Biology, University of Leipzig, Leipzig, Germany
| | - Leonard Nadler
- Institut für Biologie, Neurobiologie, Freie Universität Berlin, Berlin, Germany
| | - Amir Ayali
- School of Zoology, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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17
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Kendroud S, Bohra AA, Kuert PA, Nguyen B, Guillermin O, Sprecher SG, Reichert H, VijayRaghavan K, Hartenstein V. Structure and development of the subesophageal zone of the Drosophila brain. II. Sensory compartments. J Comp Neurol 2018; 526:33-58. [PMID: 28875566 PMCID: PMC5971197 DOI: 10.1002/cne.24316] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/15/2017] [Accepted: 08/15/2017] [Indexed: 12/29/2022]
Abstract
The subesophageal zone (SEZ) of the Drosophila brain processes mechanosensory and gustatory sensory input from sensilla located on the head, mouth cavity and trunk. Motor output from the SEZ directly controls the movements involved in feeding behavior. In an accompanying paper (Hartenstein et al., ), we analyzed the systems of fiber tracts and secondary lineages to establish reliable criteria for defining boundaries between the four neuromeres of the SEZ, as well as discrete longitudinal neuropil domains within each SEZ neuromere. Here we use this anatomical framework to systematically map the sensory projections entering the SEZ throughout development. Our findings show continuity between larval and adult sensory neuropils. Gustatory axons from internal and external taste sensilla of the larva and adult form two closely related sensory projections, (a) the anterior central sensory center located deep in the ventromedial neuropil of the tritocerebrum and mandibular neuromere, and (b) the anterior ventral sensory center (AVSC), occupying a superficial layer within the ventromedial tritocerebrum. Additional, presumed mechanosensory terminal axons entering via the labial nerve define the ventromedial sensory center (VMSC) in the maxilla and labium. Mechanosensory afferents of the massive array of chordotonal organs (Johnston's organ) of the adult antenna project into the centrolateral neuropil column of the anterior SEZ, creating the antenno-mechanosensory and motor center (AMMC). Dendritic projections of dye back-filled motor neurons extend throughout a ventral layer of the SEZ, overlapping widely with the AVSC and VMSC. Our findings elucidate fundamental structural aspects of the developing sensory systems in Drosophila.
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Affiliation(s)
- Sarah Kendroud
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ali Asgar Bohra
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, India
| | | | - Bao Nguyen
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Oriane Guillermin
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Simon G. Sprecher
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | | | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
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18
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Bidaye SS, Bockemühl T, Büschges A. Six-legged walking in insects: how CPGs, peripheral feedback, and descending signals generate coordinated and adaptive motor rhythms. J Neurophysiol 2017; 119:459-475. [PMID: 29070634 DOI: 10.1152/jn.00658.2017] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Walking is a rhythmic locomotor behavior of legged animals, and its underlying mechanisms have been the subject of neurobiological research for more than 100 years. In this article, we review relevant historical aspects and contemporary studies in this field of research with a particular focus on the role of central pattern generating networks (CPGs) and their contribution to the generation of six-legged walking in insects. Aspects of importance are the generation of single-leg stepping, the generation of interleg coordination, and how descending signals influence walking. We first review how CPGs interact with sensory signals from the leg in the generation of leg stepping. Next, we summarize how these interactions are modified in the generation of motor flexibility for forward and backward walking, curve walking, and speed changes. We then review the present state of knowledge with regard to the role of CPGs in intersegmental coordination and how CPGs might be involved in mediating descending influences from the brain for the initiation, maintenance, modification, and cessation of the motor output for walking. Throughout, we aim to specifically address gaps in knowledge, and we describe potential future avenues and approaches, conceptual and methodological, with the latter emphasizing in particular options arising from the advent of neurogenetic approaches to this field of research and its combination with traditional approaches.
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Affiliation(s)
- Salil S Bidaye
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California
| | - Till Bockemühl
- Department of Animal Physiology, Zoological Institute, University of Cologne , Cologne , Germany
| | - Ansgar Büschges
- Department of Animal Physiology, Zoological Institute, University of Cologne , Cologne , Germany
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19
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David I, Holmes P, Ayali A. Endogenous rhythm and pattern-generating circuit interactions in cockroach motor centres. Biol Open 2016; 5:1229-40. [PMID: 27422902 PMCID: PMC5051644 DOI: 10.1242/bio.018705] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cockroaches are rapid and stable runners whose gaits emerge from the intricate, and not fully resolved, interplay between endogenous oscillatory pattern-generating networks and sensory feedback that shapes their rhythmic output. Here we studied the endogenous motor output of a brainless, deafferented preparation. We monitored the pilocarpine-induced rhythmic activity of levator and depressor motor neurons in the mesothoracic and metathoracic segments in order to reveal the oscillatory networks’ architecture and interactions. Data analyses included phase relations, latencies between and overlaps of rhythmic bursts, spike frequencies, and the dependence of these parameters on cycle frequency. We found that, overall, ipsilateral connections are stronger than contralateral ones. Our findings revealed asymmetries in connectivity among the different ganglia, in which meta-to-mesothoracic ascending coupling is stronger than meso-to-metathoracic descending coupling. Within-ganglion coupling between the metathoracic hemiganglia is stronger than that in the mesothoracic ganglion. We also report differences in the role and mode of operation of homologue network units (manifested by levator and depressor nerve activity). Many observed characteristics are similar to those exhibited by intact animals, suggesting a dominant role for feedforward control in cockroach locomotion. Based on these data we posit a connectivity scheme among components of the locomotion pattern generating system. Summary: Detailed analysis of fictive motor patterns unveils endogenous characteristics of the cockroach thoracic locomotion control networks and their interrelations and enables an explanatory connectivity model.
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Affiliation(s)
- Izhak David
- Department of Zoology, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Philip Holmes
- Department of Mechanical and Aerospace Engineering, Program in Applied and Computational Mathematics, Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
| | - Amir Ayali
- Department of Zoology, Tel Aviv University, Tel Aviv 6997801, Israel Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
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20
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Gruhn M, Rosenbaum P, Bockemühl T, Büschges A. Body side-specific control of motor activity during turning in a walking animal. eLife 2016; 5. [PMID: 27130731 PMCID: PMC4894755 DOI: 10.7554/elife.13799] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/25/2016] [Indexed: 11/13/2022] Open
Abstract
Animals and humans need to move deftly and flexibly to adapt to environmental demands. Despite a large body of work on the neural control of walking in invertebrates and vertebrates alike, the mechanisms underlying the motor flexibility that is needed to adjust the motor behavior remain largely unknown. Here, we investigated optomotor-induced turning and the neuronal mechanisms underlying the differences between the leg movements of the two body sides in the stick insect Carausius morosus. We present data to show that the generation of turning kinematics in an insect are the combined result of descending unilateral commands that change the leg motor output via task-specific modifications in the processing of local sensory feedback as well as modification of the activity of local central pattern generating networks in a body-side-specific way. To our knowledge, this is the first study to demonstrate the specificity of such modifications in a defined motor task. DOI:http://dx.doi.org/10.7554/eLife.13799.001 Walking along a curve or turning is a complex manoeuvre for the nervous system, as it must coordinate different leg movements on each side of the body. Rhythmic processes such as walking are controlled by networks of neurons called central pattern generators. The resulting movements can be adjusted by feedback from sense organs in response to environmental conditions. For example, sensory feedback that provides information about the load placed on each leg, allows the animal to control the duration of a stance. How the nerve cells, or neurons, involved in these processes work together to produce complex, flexible movements such as turning is largely unknown. Previous work on how the brain negotiates turning movements has been carried out mostly in animals that swim or fly. To understand what happens during walking, Gruhn et al. monitored stick insects that walked in a curve on a slippery surface, and recorded the electrical activity within the animals' nervous system as they turned. By comparing the activity of the nervous system on each side of the body while the insects walked a curve, Gruhn et al. found that the nervous system uses at least three different mechanisms to produce the different movements on the inside and outside. Firstly, the sensory feedback signals that communicate the load on the leg are processed in the legs on the outside of the curve to support forward steps, while they are processed on the inside legs to support forward, sideward, and backward steps. Secondly, the motor activity produced by the central pattern generator is modulated to be stronger for the muscle that moves the leg backward on the outside of the curve. At the same time, this activity is stronger for the muscle that moves the leg forward on the inside of the curve. Thirdly, signals from a front leg influence the movement of the other legs on the same side of the body. This influence is strong on the inside and weak on the outside of the curve. Together or separately, these three mechanisms could provide the animal with the means to perform turns in all their different curvatures. Future work will need to work out exactly which local neurons process the signals sent from the brain to control movement. DOI:http://dx.doi.org/10.7554/eLife.13799.002
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Affiliation(s)
- Matthias Gruhn
- Department of Animal Physiology, Biocenter, University of Cologne, Cologne, Germany
| | - Philipp Rosenbaum
- Department of Animal Physiology, Biocenter, University of Cologne, Cologne, Germany
| | - Till Bockemühl
- Department of Animal Physiology, Biocenter, University of Cologne, Cologne, Germany
| | - Ansgar Büschges
- Department of Animal Physiology, Biocenter, University of Cologne, Cologne, Germany
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21
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Insect motor control: methodological advances, descending control and inter-leg coordination on the move. Curr Opin Neurobiol 2015; 33:8-15. [DOI: 10.1016/j.conb.2014.12.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/19/2014] [Accepted: 12/22/2014] [Indexed: 11/20/2022]
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22
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Kaiser M, Libersat F. The role of the cerebral ganglia in the venom-induced behavioral manipulation of cockroaches stung by the parasitoid jewel wasp. ACTA ACUST UNITED AC 2015; 218:1022-7. [PMID: 25687435 DOI: 10.1242/jeb.116491] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 01/22/2015] [Indexed: 11/20/2022]
Abstract
The jewel wasp stings cockroaches and injects venom into their cerebral ganglia, namely the subesophageal ganglion (SOG) and supraesophageal ganglion (SupOG). The venom induces a long-term hypokinetic state, during which the stung cockroach shows little or no spontaneous walking. It was shown that venom injection to the SOG reduces neuronal activity, thereby suggesting a similar effect of venom injection in the SupOG. Paradoxically, SupOG-ablated cockroaches show increased spontaneous walking in comparison with control. Yet most of the venom in the SupOG of cockroaches is primarily concentrated in and around the central complex (CX). Thus the venom could chiefly decrease activity in the CX to contribute to the hypokinetic state. Our first aim was to resolve this discrepancy by using a combination of behavioral and neuropharmacological tools. Our results show that the CX is necessary for the initiation of spontaneous walking, and that focal injection of procaine to the CX is sufficient to induce the decrease in spontaneous walking. Furthermore, it was shown that artificial venom injection to the SOG decreases walking. Hence our second aim was to test the interactions between the SupOG and SOG in the venom-induced behavioral manipulation. We show that, in the absence of the inhibitory control of the SupOG on walking initiation, injection of venom in the SOG alone by the wasp is sufficient to induce the hypokinetic state. To summarize, we show that venom injection to either the SOG or the CX of the SupOG is, by itself, sufficient to decrease walking.
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Affiliation(s)
- Maayan Kaiser
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Frederic Libersat
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
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23
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Libersat F, Gal R. Wasp Voodoo Rituals, Venom-Cocktails, and the Zombification of Cockroach Hosts. Integr Comp Biol 2014; 54:129-42. [DOI: 10.1093/icb/icu006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Gal R, Kaiser M, Haspel G, Libersat F. Sensory arsenal on the stinger of the parasitoid jewel wasp and its possible role in identifying cockroach brains. PLoS One 2014; 9:e89683. [PMID: 24586962 PMCID: PMC3935893 DOI: 10.1371/journal.pone.0089683] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 01/22/2014] [Indexed: 11/25/2022] Open
Abstract
The parasitoid jewel wasp uses cockroaches as live food supply for its developing larva. To this end, the adult wasp stings a cockroach and injects venom directly inside its brain, turning the prey into a submissive ‘zombie’. Here, we characterize the sensory arsenal on the wasp’s stinger that enables the wasp to identify the brain target inside the cockroach’s head. An electron microscopy study of the stinger reveals (a) cuticular depressions innervated by a single mechanosensory neuron, which are presumably campaniform sensilla; and (b) dome-shaped structures innervated by a single mechanosensory neuron and 4–5 chemosensory neurons, which are presumably contact-chemoreceptive sensilla. Extracellular electrophysiological recordings from stinger afferents show increased firing rate in response to mechanical stimulation with agarose. This response is direction-selective and depends upon the concentration (density) of the agarose, such that the most robust response is evoked when the stinger is stimulated in the distal-to-proximal direction (concomitant with the penetration during the natural stinging behavior) and penetrating into relatively hard (0.75%–2.5%) agarose pellets. Accordingly, wasps demonstrate a normal stinging behavior when presented with cockroaches in which the brain was replaced with a hard (2.5%) agarose pellet. Conversely, wasps demonstrate a prolonged stinging behavior when the cockroach brain was either removed or replaced by a soft (0.5%) agarose pellet, or when stinger sensory organs were ablated prior to stinging. We conclude that the parasitoid jewel wasp uses at least mechanosensory inputs from its stinger to identify the brain within the head capsule of the cockroach prey.
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Affiliation(s)
- Ram Gal
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- * E-mail:
| | - Maayan Kaiser
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Gal Haspel
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
| | - Frederic Libersat
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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25
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Kai K, Okada J. Characterization of locomotor-related spike activity in protocerebrum of freely walking cricket. Zoolog Sci 2013; 30:591-601. [PMID: 23829220 DOI: 10.2108/zsj.30.591] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
To characterize the neural elements involved in the higher-order control of spontaneous walking in insects, we recorded extracellular spike activity in the protocerebrum of freely walking crickets (Gryllus bimaculatus). Locomotor behavior was simultaneously recorded using a newly developed motion tracking system. We focused on spike units that altered their firing patterns during walking. According to their activity patterns with reference to walking bouts, these locomotor-related spike units were classified into the following four types: continuously activated unit during walking (type 1); continuously inhibited unit during walking (type 2); transiently activated unit at the onset of walking (type 3); and transiently activated unit at the termination of walking (type 4). The type 1 unit was the most dominant group (25 out of 33 units), whereas only a few units each were recorded for types 2-4. Some of the locomotor-related units tended to change firing pattern before the onset or termination of walking bouts. Spike activity in some type 1 units was found to be closely correlated with walking speed. When firing timing was compared between unit pairs, their temporal relationships (synchronization/desynchronization) altered, depending on the behavioral state (standing/walking). Mechanical stimuli applied to the body surface elicited excitatory responses in the majority of the units. Histological observations revealed that the recorded sites were concentrated near or within the mushroom body and central complex in the protocerebrum.
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Affiliation(s)
- Kazuki Kai
- Graduate School of Science and Technology, Nagasaki University, Nagasaki 852-8521, Japan
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26
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Abstract
How are stereotyped behaviors organized in a simple nervous system? A new study in the Drosophila larva reports that the foraging routine can be performed in the absence of any input from the brain.
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27
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Libersat F, Gal R. What can parasitoid wasps teach us about decision-making in insects? J Exp Biol 2013; 216:47-55. [DOI: 10.1242/jeb.073999] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
Millions of years of co-evolution have driven parasites to display very complex and exquisite strategies to manipulate the behaviour of their hosts. However, although parasite-induced behavioural manipulation is a widespread phenomenon, the underlying neuronal mechanisms are only now beginning to be deciphered. Here, we review recent advancements in the study of the mechanisms by which parasitoid wasps use chemical warfare to manipulate the behaviour of their insect hosts. We focus on a particular case study in which a parasitoid wasp (the jewel wasp Ampulex compressa) performs a delicate brain surgery on its prey (the American cockroach Periplaneta americana) to take away its motivation to initiate locomotion. Following a brief background account of parasitoid wasps that manipulate host behaviour, we survey specific aspects of the unique effects of the A. compressa venom on the regulation of spontaneous and evoked behaviour in the cockroach host.
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Affiliation(s)
- Frederic Libersat
- Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be’er Sheva, 84105Israel
| | - Ram Gal
- Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be’er Sheva, 84105Israel
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28
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Büschges A. Lessons for circuit function from large insects: towards understanding the neural basis of motor flexibility. Curr Opin Neurobiol 2012; 22:602-8. [PMID: 22386530 DOI: 10.1016/j.conb.2012.02.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/06/2012] [Accepted: 02/07/2012] [Indexed: 11/30/2022]
Abstract
Motor behaviors result from information processing that occurs in multiple neural networks acting at all levels from the initial selection of the behavior to its final generation. A long-standing research interest is how single neural networks can help generate different motor behaviors, that is, the origin of motor flexibility. Modern experimental techniques allow studying neural network activity during the production of multiple motor behaviors. Recent data provide strong evidence that the neural networks controlling insect legs are individually modified in task-dependent and finely tuned fashions. Understanding the mechanistic basis of these neural network modifications will be of particular interest in the upcoming years.
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Affiliation(s)
- Ansgar Büschges
- Zoological Institute, Biocenter Cologne, University of Cologne, Zülpicher Straße 47b, 50674 Cologne, Germany.
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29
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Mullins OJ, Friesen WO. The brain matters: effects of descending signals on motor control. J Neurophysiol 2012; 107:2730-41. [PMID: 22378172 DOI: 10.1152/jn.00107.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability of nerve cords and spinal cords to exhibit fictive rhythmic locomotion in the absence of the brain is well-documented in numerous species. Although the brain is important for modulating the fictive motor output, it is broadly assumed that the functional properties of neuronal circuits identified in simplified preparations are conserved with the brain attached. We tested this assumption by examining the properties of a novel interneuron recently identified in the leech (Hirudo verbana) nerve cord. This neuron, cell E21, initiates and drives stereotyped fictive swimming activity in preparations of the isolated leech nerve cord deprived of the head brain. We report that, contrary to expectation, the motor output generated when cell E21 is stimulated in preparations with the brain attached is highly variable. Swim frequency and episode duration are increased in some of these preparations and decreased in others. Cell E21 controls swimming, in part, via excitatory synaptic interactions with cells 204, previously identified gating neurons that reliably initiate and strongly enhance leech swimming activity when the brain is absent. We found that in preparations with the brain present, the magnitude of the synaptic interaction from cell E21 to cell 204 is reduced by 50% and that cell 204-evoked responses also were highly variable. Intriguingly, most of this variability disappeared in semi-intact preparations. We conclude that neuronal circuit properties identified in reduced preparations might be fundamentally altered from those that occur in more physiological conditions.
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Affiliation(s)
- Olivia J Mullins
- Dept. of Biology, Univ. of Virginia, Charlottesville, VA 22904-4328, USA.
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Biogenic amines in the nervous system of the cockroach, Periplaneta americana following envenomation by the jewel wasp, Ampulex compressa. Toxicon 2012; 59:320-8. [DOI: 10.1016/j.toxicon.2011.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 10/13/2011] [Accepted: 10/19/2011] [Indexed: 11/30/2022]
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Mullins OJ, Brodfuehrer PD, Jusufović S, Hackett JT, Friesen WO. Specialized brain regions and sensory inputs that control locomotion in leeches. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 198:97-108. [PMID: 22037913 DOI: 10.1007/s00359-011-0691-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 10/11/2011] [Accepted: 10/11/2011] [Indexed: 11/26/2022]
Abstract
Locomotor systems are often controlled by specialized cephalic neurons and undergo modulation by sensory inputs. In many species, dedicated brain regions initiate and maintain behavior and set the duration and frequency of the locomotor episode. In the leech, removing the entire head brain enhances swimming, but the individual roles of its components, the supra- and subesophageal ganglia, in the control of locomotion are unknown. Here we describe the influence of these two structures and that of the tail brain on rhythmic swimming in isolated nerve cord preparations and in nearly intact leeches suspended in an aqueous, "swim-enhancing" environment. We found that, in isolated preparations, swim episode duration and swim burst frequency are greatly increased when the supraesophageal ganglion is removed, but the subesophageal ganglion is intact. The prolonged swim durations observed with the anterior-most ganglion removed were abolished by removal of the tail ganglion. Experiments on the nearly intact leeches show that, in these preparations, the subesophageal ganglion acts to decrease cycle period but, unexpectedly, also decreases swim duration. These results suggest that the supraesophageal ganglion is the primary structure that constrains leech swimming; however, the control of swim duration in the leech is complex, especially in the intact animal.
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Affiliation(s)
- Olivia J Mullins
- Department of Biology, University of Virginia, P.O. Box 400328, Charlottesville, VA 22904-4328, USA
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Iyengar BG, Chou CJ, Vandamme KM, Klose MK, Zhao X, Akhtar-Danesh N, Campos AR, Atwood HL. Silencing synaptic communication between random interneurons duringDrosophilalarval locomotion. GENES BRAIN AND BEHAVIOR 2011; 10:883-900. [DOI: 10.1111/j.1601-183x.2011.00729.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Gal R, Libersat F. On predatory wasps and zombie cockroaches: Investigations of "free will" and spontaneous behavior in insects. Commun Integr Biol 2011; 3:458-61. [PMID: 21057640 DOI: 10.4161/cib.3.5.12472] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 05/25/2010] [Indexed: 11/19/2022] Open
Abstract
Accumulating evidence suggest that nonhuman organisms, including invertebrates, possess the ability to make non-random choices based purely on ongoing and endogenously-created neuronal processes. We study this precursor of spontaneity in cockroaches stung by A. compressa, a parasitoid wasp that employs cockroaches as a live food supply for its offspring. This wasp uses a neurotoxic venom cocktail to 'hijack' the nervous system of its cockroach prey and manipulate specific features of its decision making process, thereby turning the cockroach into a submissive 'zombie' unable to self-initiate locomotion. We discuss different behavioral and physiological aspects of this venom-induced 'zombified state' and highlight at least one neuronal substrate involved in the regulation of spontaneous behavior in insects.
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Affiliation(s)
- Ram Gal
- Department of Life Sciences; Ben-Gurion University of the Negev; Be'er-Sheva, Israel
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Gavra T, Libersat F. Involvement of the opioid system in the hypokinetic state induced in cockroaches by a parasitoid wasp. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2010; 197:279-91. [DOI: 10.1007/s00359-010-0610-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 11/01/2010] [Accepted: 11/04/2010] [Indexed: 11/24/2022]
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A mathematical modeling study of inter-segmental coordination during stick insect walking. J Comput Neurosci 2010; 30:255-78. [DOI: 10.1007/s10827-010-0254-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Revised: 05/26/2010] [Accepted: 06/01/2010] [Indexed: 10/19/2022]
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Gal R, Libersat F. A wasp manipulates neuronal activity in the sub-esophageal ganglion to decrease the drive for walking in its cockroach prey. PLoS One 2010; 5:e10019. [PMID: 20383324 PMCID: PMC2850919 DOI: 10.1371/journal.pone.0010019] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 03/11/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The parasitoid Jewel Wasp hunts cockroaches to serve as a live food supply for its offspring. The wasp stings the cockroach in the head and delivers a cocktail of neurotoxins directly inside the prey's cerebral ganglia. Although not paralyzed, the stung cockroach becomes a living yet docile 'zombie', incapable of self-initiating spontaneous or evoked walking. We show here that such neuro-chemical manipulation can be attributed to decreased neuronal activity in a small region of the cockroach cerebral nervous system, the sub-esophageal ganglion (SEG). A decrease in descending permissive inputs from this ganglion to thoracic central pattern generators decreases the propensity for walking-related behaviors. METHODOLOGY AND PRINCIPAL FINDINGS We have used behavioral, neuro-pharmacological and electrophysiological methods to show that: (1) Surgically removing the cockroach SEG prior to wasp stinging prolongs the duration of the sting 5-fold, suggesting that the wasp actively targets the SEG during the stinging sequence; (2) injecting a sodium channel blocker, procaine, into the SEG of non-stung cockroaches reversibly decreases spontaneous and evoked walking, suggesting that the SEG plays an important role in the up-regulation of locomotion; (3) artificial focal injection of crude milked venom into the SEG of non-stung cockroaches decreases spontaneous and evoked walking, as seen with naturally-stung cockroaches; and (4) spontaneous and evoked neuronal spiking activity in the SEG, recorded with an extracellular bipolar microelectrode, is markedly decreased in stung cockroaches versus non-stung controls. CONCLUSIONS AND SIGNIFICANCE We have identified the neuronal substrate responsible for the venom-induced manipulation of the cockroach's drive for walking. Our data strongly support previous findings suggesting a critical and permissive role for the SEG in the regulation of locomotion in insects. By injecting a venom cocktail directly into the SEG, the parasitoid Jewel Wasp selectively manipulates the cockroach's motivation to initiate walking without interfering with other non-related behaviors.
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Affiliation(s)
- Ram Gal
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
- * E-mail: (RG); (FL)
| | - Frederic Libersat
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
- Institut de Neurobiologie de la Méditerranée INSERM U901, Université de la Méditerranée, Parc Scientifique de Luminy, Marseille, France
- * E-mail: (RG); (FL)
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Libersat F, Delago A, Gal R. Manipulation of host behavior by parasitic insects and insect parasites. ANNUAL REVIEW OF ENTOMOLOGY 2009; 54:189-207. [PMID: 19067631 DOI: 10.1146/annurev.ento.54.110807.090556] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Parasites often alter the behavior of their hosts in ways that are ultimately beneficial to the parasite or its offspring. Although the alteration of host behavior by parasites is a widespread phenomenon, the underlying neuronal mechanisms are only beginning to be understood. Here, we focus on recent advances in the study of behavioral manipulation via modulation of the host central nervous system. We elaborate on a few case studies, in which recently published data provide explanations for the neuronal basis of parasite-induced alteration of host behavior. Among these, we describe how a worm may influence the nervous system of its cricket host and manipulate the cricket into committing suicide by jumping into water. We then focus on Ampulex compressa, which uses an Alien-like strategy for the sake of its offspring. Unlike most venomous hunters, this wasp injects venom directly into specific cerebral regions of its cockroach prey. As a result of the sting, the cockroach remains alive but immobile, but not paralyzed, and serves to nourish the developing wasp larva.
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Affiliation(s)
- Frederic Libersat
- Institut de Neurobiologie de la Méditerranée, Parc scientifique de Luminy, BP13, 13273 Marseille cedex 09, France.
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Gal R, Libersat F. A Parasitoid Wasp Manipulates the Drive for Walking of Its Cockroach Prey. Curr Biol 2008; 18:877-82. [DOI: 10.1016/j.cub.2008.04.076] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 04/18/2008] [Accepted: 04/29/2008] [Indexed: 11/26/2022]
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Rosenberg LA, Glusman JG, Libersat F. Octopamine partially restores walking in hypokinetic cockroaches stung by the parasitoid waspAmpulex compressa. J Exp Biol 2007; 210:4411-7. [DOI: 10.1242/jeb.010488] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYWhen stung by the parasitoid wasp Ampulex compressa, cockroaches Periplaneta americana enter a hypokinetic state that is characterized by little, if any, spontaneous locomotor activity. In the present study we investigate the effect of an octopamine receptor agonist and an antagonist on the locomotor behavior of stung and control cockroaches. We show that in cockroaches stung by a wasp the octopamine receptor agonist chlordimeform induces a significant increase in spontaneous walking. In good agreement, in control individuals an octopamine receptor antagonist significantly reduces walking activity. Adipokinetic hormone I (AKH-I) promotes spontaneous walking in controls but does not do so in stung individuals, which suggests that the venom effect is most probably not mediated by AKH-I. Dopamine receptor agonists or antagonists had no significant effect on the spontaneous walking of stung or control cockroaches, respectively. The effect of the octopamine receptor agonist was maximal when injected into the brain, suggesting that the wasp venom interferes with octopaminergic modulation of walking initiation in central structures of the cockroach brain.
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Affiliation(s)
- Lior Ann Rosenberg
- Department of Life Sciences and Zlotowski Center for Neuroscience,Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Jose Gustavo Glusman
- Department of Life Sciences and Zlotowski Center for Neuroscience,Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Frederic Libersat
- Department of Life Sciences and Zlotowski Center for Neuroscience,Ben-Gurion University of the Negev, Beer Sheva, Israel
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Socha JJ, Westneat MW, Harrison JF, Waters JS, Lee WK. Real-time phase-contrast x-ray imaging: a new technique for the study of animal form and function. BMC Biol 2007; 5:6. [PMID: 17331247 PMCID: PMC1831761 DOI: 10.1186/1741-7007-5-6] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2007] [Accepted: 03/01/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite advances in imaging techniques, real-time visualization of the structure and dynamics of tissues and organs inside small living animals has remained elusive. Recently, we have been using synchrotron x-rays to visualize the internal anatomy of millimeter-sized opaque, living animals. This technique takes advantage of partially-coherent x-rays and diffraction to enable clear visualization of internal soft tissue not viewable via conventional absorption radiography. However, because higher quality images require greater x-ray fluxes, there exists an inherent tradeoff between image quality and tissue damage. RESULTS We evaluated the tradeoff between image quality and harm to the animal by determining the impact of targeted synchrotron x-rays on insect physiology, behavior and survival. Using 25 keV x-rays at a flux density of 80 microW/mm-2, high quality video-rate images can be obtained without major detrimental effects on the insects for multiple minutes, a duration sufficient for many physiological studies. At this setting, insects do not heat up. Additionally, we demonstrate the range of uses of synchrotron phase-contrast imaging by showing high-resolution images of internal anatomy and observations of labeled food movement during ingestion and digestion. CONCLUSION Synchrotron x-ray phase contrast imaging has the potential to revolutionize the study of physiology and internal biomechanics in small animals. This is the only generally applicable technique that has the necessary spatial and temporal resolutions, penetrating power, and sensitivity to soft tissue that is required to visualize the internal physiology of living animals on the scale from millimeters to microns.
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Affiliation(s)
- John J Socha
- Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439, USA
| | - Mark W Westneat
- Department of Zoology, Field Museum of Natural History, 1400 S. Lake Shore Dr., Chicago, IL, 60605, USA
| | - Jon F Harrison
- Section of Organismal, Integrative, and Systems Biology, School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ, 85287-4501, USA
| | - James S Waters
- Section of Organismal, Integrative, and Systems Biology, School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ, 85287-4501, USA
| | - Wah-Keat Lee
- Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439, USA
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