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Golding D, Rupp KL, Sustar A, Pratt B, Tuthill JC. Snow flies self-amputate freezing limbs to sustain behavior at sub-zero temperatures. Curr Biol 2023; 33:4549-4556.e3. [PMID: 37757830 PMCID: PMC10842534 DOI: 10.1016/j.cub.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/02/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023]
Abstract
Temperature profoundly impacts all living creatures. In spite of the thermodynamic constraints on biology, some animals have evolved to live and move in extremely cold environments. Here, we investigate behavioral mechanisms of cold tolerance in the snow fly (Chionea spp.), a flightless crane fly that is active throughout the winter in boreal and alpine environments of the northern hemisphere. Using thermal imaging, we show that adult snow flies maintain the ability to walk down to an average body temperature of -7°C. At this supercooling limit, ice crystallization occurs within the snow fly's hemolymph and rapidly spreads throughout the body, resulting in death. However, we discovered that snow flies frequently survive freezing by rapidly amputating legs before ice crystallization can spread to their vital organs. Self-amputation of freezing limbs is a last-ditch tactic to prolong survival in frigid conditions that few animals can endure. Understanding the extreme physiology and behavior of snow insects holds particular significance at this moment when their alpine habitats are rapidly changing due to anthropogenic climate change. VIDEO ABSTRACT.
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Affiliation(s)
- Dominic Golding
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Katie L Rupp
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Anne Sustar
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Brandon Pratt
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - John C Tuthill
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA.
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2
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Akbar SA, Kanturski M, Barták M, Wachkoo AA, Maqbool A. SEM studies and discovery of an intriguing new Rhamphomyia ( Pararhamphomyia) (Diptera, Empididae, Empidinae) species from the Kashmir Himalayas. THE EUROPEAN ZOOLOGICAL JOURNAL 2022. [DOI: 10.1080/24750263.2022.2139864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Affiliation(s)
- S. A. Akbar
- Division of Plant Protection; Department of Entomology, Central Institute of Temperate Horticulture, Srinagar, India
| | - M. Kanturski
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - M. Barták
- Faculty of Agrobiology, Food and Natural Resources, Department of Zoology and Fisheries, Czech University of Life Sciences, Czechia
| | - A. A. Wachkoo
- Department of Zoology, Imtiyaz Memorial Government Degree College, Shopian, India
| | - A. Maqbool
- Department of Zoology, Government College for Women, Srinagar, India
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3
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Gebehart C, Hooper SL, Büschges A. Non-linear multimodal integration in a distributed premotor network controls proprioceptive reflex gain in the insect leg. Curr Biol 2022; 32:3847-3854.e3. [PMID: 35896118 DOI: 10.1016/j.cub.2022.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/30/2022] [Accepted: 07/05/2022] [Indexed: 11/28/2022]
Abstract
Producing context-appropriate motor acts requires integrating multiple sensory modalities. Presynaptic inhibition of proprioceptive afferent neurons1-4 and afferents of different modalities targeting the same motor neurons (MNs)5-7 underlies some of this integration. However, in most systems, an interneuronal network is interposed between sensory afferents and MNs. How these networks contribute to this integration, particularly at single-neuron resolution, is little understood. Context-specific integration of load and movement sensory inputs occurs in the stick insect locomotory system,6,8-12 and both inputs feed into a network of premotor nonspiking interneurons (NSIs).8 We analyzed how load altered movement signal processing in the stick insect femur-tibia (FTi) joint control system by tracing the interaction of FTi movement13-15 (femoral chordotonal organ [fCO]) and load13,15,16 (tibial campaniform sensilla [CS]) signals through the NSI network to the slow extensor tibiae (SETi) MN, the extensor MN primarily active in non-walking animals.17-19 On the afferent level, load reduced movement signal gain by presynaptic inhibition. In the NSI network, graded responses to movement and load inputs summed nonlinearly, increasing the gain of NSIs opposing movement-induced reflexes and thus decreasing the SETi and extensor tibiae muscle movement reflex responses. Gain modulation was movement-parameter specific and required presynaptic inhibition. These data suggest that gain changes in distributed premotor networks, specifically the relative weighting of antagonistic pathways, could be a general mechanism by which multiple sensory modalities are integrated to generate context-appropriate motor activity.
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Affiliation(s)
- Corinna Gebehart
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Zülpicher Strasse 47b, 50674 Cologne, Germany.
| | - Scott L Hooper
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Zülpicher Strasse 47b, 50674 Cologne, Germany; Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Ansgar Büschges
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Zülpicher Strasse 47b, 50674 Cologne, Germany
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4
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NeuroMechFly, a neuromechanical model of adult Drosophila melanogaster. Nat Methods 2022; 19:620-627. [PMID: 35545713 DOI: 10.1038/s41592-022-01466-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 03/23/2022] [Indexed: 11/08/2022]
Abstract
Animal behavior emerges from an interaction between neural network dynamics, musculoskeletal properties and the physical environment. Accessing and understanding the interplay between these elements requires the development of integrative and morphologically realistic neuromechanical simulations. Here we present NeuroMechFly, a data-driven model of the widely studied organism, Drosophila melanogaster. NeuroMechFly combines four independent computational modules: a physics-based simulation environment, a biomechanical exoskeleton, muscle models and neural network controllers. To enable use cases, we first define the minimum degrees of freedom of the leg from real three-dimensional kinematic measurements during walking and grooming. Then, we show how, by replaying these behaviors in the simulator, one can predict otherwise unmeasured torques and contact forces. Finally, we leverage NeuroMechFly's full neuromechanical capacity to discover neural networks and muscle parameters that drive locomotor gaits optimized for speed and stability. Thus, NeuroMechFly can increase our understanding of how behaviors emerge from interactions between complex neuromechanical systems and their physical surroundings.
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5
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Dinges GF, Bockemühl T, Iacoviello F, Shearing PR, Büschges A, Blanke A. Ultra high-resolution biomechanics suggest that substructures within insect mechanosensors decisively affect their sensitivity. J R Soc Interface 2022; 19:20220102. [PMID: 35506211 PMCID: PMC9065962 DOI: 10.1098/rsif.2022.0102] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Insect load sensors, called campaniform sensilla (CS), measure strain changes within the cuticle of appendages. This mechanotransduction provides the neuromuscular system with feedback for posture and locomotion. Owing to their diverse morphology and arrangement, CS can encode different strain directions. We used nano-computed tomography and finite-element analysis to investigate how different CS morphologies within one location—the femoral CS field of the leg in the fruit fly Drosophila—interact under load. By investigating the influence of CS substructures' material properties during simulated limb displacement with naturalistic forces, we could show that CS substructures (i.e. socket and collar) influence strain distribution throughout the whole CS field. Altered socket and collar elastic moduli resulted in 5% relative differences in displacement, and the artificial removal of all sockets caused differences greater than 20% in cap displacement. Apparently, CS sockets support the distribution of distal strain to more proximal CS, while collars alter CS displacement more locally. Harder sockets can increase or decrease CS displacement depending on sensor location. Furthermore, high-resolution imaging revealed that sockets are interconnected in subcuticular rows. In summary, the sensitivity of individual CS is dependent on the configuration of other CS and their substructures.
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Affiliation(s)
- Gesa F Dinges
- Institute of Zoology, University of Cologne, 50674 Cologne, Germany
| | - Till Bockemühl
- Institute of Zoology, University of Cologne, 50674 Cologne, Germany
| | - Francesco Iacoviello
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, WC1DE 6BT London, UK
| | - Paul R Shearing
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, WC1DE 6BT London, UK
| | - Ansgar Büschges
- Institute of Zoology, University of Cologne, 50674 Cologne, Germany
| | - Alexander Blanke
- Institute of Zoology, University of Cologne, 50674 Cologne, Germany.,Institute of Evolutionary Biology and Ecology, University of Bonn, 53121 Bonn, Germany
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6
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Hammel E, Mantziaris C, Schmitz J, Büschges A, Gruhn M. Thorax-Segment- and Leg-Segment-Specific Motor Control for Adaptive Behavior. Front Physiol 2022; 13:883858. [PMID: 35600292 PMCID: PMC9114818 DOI: 10.3389/fphys.2022.883858] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/20/2022] [Indexed: 12/03/2022] Open
Abstract
We have just started to understand the mechanisms underlying flexibility of motor programs among segmental neural networks that control each individual leg during walking in vertebrates and invertebrates. Here, we investigated the mechanisms underlying curve walking in the stick insect Carausius morosus during optomotor-induced turning. We wanted to know, whether the previously reported body-side specific changes in a two-front leg turning animal are also observed in the other thoracic leg segments. The motor activity of the three major leg joints showed three types of responses: 1) a context-dependent increase or decrease in motor neuron (MN) activity of the antagonistic MN pools of the thorax-coxa (ThC)-joint during inside and outside turns; 2) an activation of 1 MN pool with simultaneous cessation of the other, independent of the turning direction in the coxa-trochanteral (CTr)-joint; 3) a modification in the activity of both FTi-joint MN pools which depended on the turning direction in one, but not in the other thorax segment. By pharmacological activation of the meso- or metathoracic central pattern generating networks (CPG), we show that turning-related modifications in motor output involve changes to local CPG activity. The rhythmic activity in the MN pools of the ThC and CTr-joints was modified similarly to what was observed under control conditions in saline. Our results indicate that changes in meso- and metathoracic motor activity during curve walking are leg-joint- and thorax-segment-specific, can depend on the turning direction, and are mediated through changes in local CPG activity.
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7
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Harris CM, Dinges GF, Haberkorn A, Gebehart C, Büschges A, Zill SN. Gradients in mechanotransduction of force and body weight in insects. ARTHROPOD STRUCTURE & DEVELOPMENT 2020; 58:100970. [PMID: 32702647 DOI: 10.1016/j.asd.2020.100970] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Posture and walking require support of the body weight, which is thought to be detected by sensory receptors in the legs. Specificity in sensory encoding occurs through the numerical distribution, size and response range of sense organs. We have studied campaniform sensilla, receptors that detect forces as strains in the insect exoskeleton. The sites of mechanotransduction (cuticular caps) were imaged by light and confocal microscopy in four species (stick insects, cockroaches, blow flies and Drosophila). The numbers of receptors and cap diameters were determined in projection images. Similar groups of receptors are present in the legs of each species (flies lack Group 2 on the anterior trochanter). The number of receptors is generally related to the body weight but similar numbers are found in blow flies and Drosophila, despite a 30 fold difference in their weight. Imaging data indicate that the gradient (range) of cap sizes may more closely correlate with the body weight: the range of cap sizes is larger in blow flies than in Drosophila but similar to that found in juvenile cockroaches. These studies support the idea that morphological properties of force-detecting sensory receptors in the legs may be tuned to reflect the body weight.
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Affiliation(s)
- Christian M Harris
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25704, USA
| | - Gesa F Dinges
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Anna Haberkorn
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Corinna Gebehart
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Ansgar Büschges
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Sasha N Zill
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25704, USA.
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8
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Location and arrangement of campaniform sensilla in
Drosophila melanogaster. J Comp Neurol 2020; 529:905-925. [DOI: 10.1002/cne.24987] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/19/2020] [Accepted: 07/01/2020] [Indexed: 11/07/2022]
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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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Dürr V, Arena PP, Cruse H, Dallmann CJ, Drimus A, Hoinville T, Krause T, Mátéfi-Tempfli S, Paskarbeit J, Patanè L, Schäffersmann M, Schilling M, Schmitz J, Strauss R, Theunissen L, Vitanza A, Schneider A. Integrative Biomimetics of Autonomous Hexapedal Locomotion. Front Neurorobot 2019; 13:88. [PMID: 31708765 PMCID: PMC6819508 DOI: 10.3389/fnbot.2019.00088] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/07/2019] [Indexed: 01/31/2023] Open
Abstract
Despite substantial advances in many different fields of neurorobotics in general, and biomimetic robots in particular, a key challenge is the integration of concepts: to collate and combine research on disparate and conceptually disjunct research areas in the neurosciences and engineering sciences. We claim that the development of suitable robotic integration platforms is of particular relevance to make such integration of concepts work in practice. Here, we provide an example for a hexapod robotic integration platform for autonomous locomotion. In a sequence of six focus sections dealing with aspects of intelligent, embodied motor control in insects and multipedal robots-ranging from compliant actuation, distributed proprioception and control of multiple legs, the formation of internal representations to the use of an internal body model-we introduce the walking robot HECTOR as a research platform for integrative biomimetics of hexapedal locomotion. Owing to its 18 highly sensorized, compliant actuators, light-weight exoskeleton, distributed and expandable hardware architecture, and an appropriate dynamic simulation framework, HECTOR offers many opportunities to integrate research effort across biomimetics research on actuation, sensory-motor feedback, inter-leg coordination, and cognitive abilities such as motion planning and learning of its own body size.
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Affiliation(s)
- Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Paolo P. Arena
- DIEEI: Dipartimento di Ingegneria Elettrica Elettronica e Informatica, Università degli Studi di Catania, Catania, Italy
| | - Holk Cruse
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Chris J. Dallmann
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Alin Drimus
- Mads Clausen Institute, University of Southern Denmark, Sønderborg, Denmark
| | - Thierry Hoinville
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Tammo Krause
- Institut für Entwicklungsbiologie und Neurobiologie, Johannes Gutenberg-Universität, Mainz, Germany
| | | | - Jan Paskarbeit
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Luca Patanè
- DIEEI: Dipartimento di Ingegneria Elettrica Elettronica e Informatica, Università degli Studi di Catania, Catania, Italy
| | - Mattias Schäffersmann
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Malte Schilling
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Josef Schmitz
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Roland Strauss
- Institut für Entwicklungsbiologie und Neurobiologie, Johannes Gutenberg-Universität, Mainz, Germany
| | - Leslie Theunissen
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Alessandra Vitanza
- DIEEI: Dipartimento di Ingegneria Elettrica Elettronica e Informatica, Università degli Studi di Catania, Catania, Italy
| | - Axel Schneider
- Cognitive Interaction Technology: Center of Excellence, Bielefeld University, Bielefeld, Germany
- Institute of System Dynamics and Mechatronics, Bielefeld University of Applied Sciences, Bielefeld, Germany
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11
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Haberkorn A, Gruhn M, Zill SN, Büschges A. Identification of the origin of force-feedback signals influencing motor neurons of the thoraco-coxal joint in an insect. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:253-270. [DOI: 10.1007/s00359-019-01334-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/23/2019] [Accepted: 03/25/2019] [Indexed: 11/28/2022]
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12
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Zill SN, Dallmann CJ, Büschges A, Chaudhry S, Schmitz J. Force dynamics and synergist muscle activation in stick insects: the effects of using joint torques as mechanical stimuli. J Neurophysiol 2018; 120:1807-1823. [PMID: 30020837 DOI: 10.1152/jn.00371.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Many sensory systems are tuned to specific parameters of behaviors and have effects that are task-specific. We have studied how force feedback contributes to activation of synergist muscles in serially homologous legs of stick insects. Forces were applied using conventional half-sine or ramp and hold functions. We also utilized waveforms of joint torques calculated from experiments in freely walking animals. In all legs, forces applied to either the tarsus (foot) or proximal leg segment (trochanter) activated synergist muscles that generate substrate grip and support, but coupling of the depressor muscle to tarsal forces was weak in the front legs. Activation of trochanteral receptors using ramp and hold functions generated positive feedback to the depressor muscle in all legs when animals were induced to seek substrate grip. However, discharges of the synergist flexor muscle showed adaptation at moderate force levels. In contrast, application of forces using torque waveforms, which do not have a static hold phase, produced sustained discharges in muscle synergies with little adaptation. Firing frequencies reflected the magnitude of ground reaction forces, were graded to changes in force amplitude, and could also be modulated by transient force perturbations added to the waveforms. Comparison of synergist activation by torques and ramp and hold functions revealed a strong influence of force dynamics (dF/d t). These studies support the idea that force receptors can act to tune muscle synergies synchronously to the range of force magnitudes and dynamics that occur in each leg according to their specific use in behavior. NEW & NOTEWORTHY The effects of force receptors (campaniform sensilla) on leg muscles and synergies were characterized in stick insects using both ramp and hold functions and waveforms of joint torques calculated by inverse dynamics. Motor responses were sustained and showed reduced adaptation to the more "natural" and nonlinear torque stimuli. Calculation of the first derivative (dF/d t) of the torque waveforms demonstrated that this difference was correlated with the dynamic sensitivities of the system.
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Affiliation(s)
- Sasha N Zill
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia
| | - Chris J Dallmann
- Department of Biological Cybernetics, Bielefeld University , Bielefeld , Germany
| | - Ansgar Büschges
- Department of Animal Physiology, Institute of Zoology, Biocenter, University of Cologne , Cologne , Germany
| | - Sumaiya Chaudhry
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia
| | - Josef Schmitz
- Department of Biological Cybernetics, Bielefeld University , Bielefeld , Germany
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13
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Dallmann CJ, Hoinville T, Dürr V, Schmitz J. A load-based mechanism for inter-leg coordination in insects. Proc Biol Sci 2018; 284:rspb.2017.1755. [PMID: 29187626 PMCID: PMC5740276 DOI: 10.1098/rspb.2017.1755] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/26/2017] [Indexed: 11/17/2022] Open
Abstract
Animals rely on an adaptive coordination of legs during walking. However, which specific mechanisms underlie coordination during natural locomotion remains largely unknown. One hypothesis is that legs can be coordinated mechanically based on a transfer of body load from one leg to another. To test this hypothesis, we simultaneously recorded leg kinematics, ground reaction forces and muscle activity in freely walking stick insects (Carausius morosus). Based on torque calculations, we show that load sensors (campaniform sensilla) at the proximal leg joints are well suited to encode the unloading of the leg in individual steps. The unloading coincides with a switch from stance to swing muscle activity, consistent with a load reflex promoting the stance-to-swing transition. Moreover, a mechanical simulation reveals that the unloading can be ascribed to the loading of a specific neighbouring leg, making it exploitable for inter-leg coordination. We propose that mechanically mediated load-based coordination is used across insects analogously to mammals.
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Affiliation(s)
- Chris J Dallmann
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, 33615, Germany .,Cognitive Interaction Technology Center of Excellence, Bielefeld University, Bielefeld, 33615, Germany
| | - Thierry Hoinville
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, 33615, Germany.,Cognitive Interaction Technology Center of Excellence, Bielefeld University, Bielefeld, 33615, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, 33615, Germany.,Cognitive Interaction Technology Center of Excellence, Bielefeld University, Bielefeld, 33615, Germany
| | - Josef Schmitz
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, 33615, Germany .,Cognitive Interaction Technology Center of Excellence, Bielefeld University, Bielefeld, 33615, Germany
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14
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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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15
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Schilder RJ, Raynor M. Molecular plasticity and functional enhancements of leg muscles in response to hypergravity in the fruit fly Drosophila melanogaster. ACTA ACUST UNITED AC 2017; 220:3508-3518. [PMID: 28978639 DOI: 10.1242/jeb.160523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/24/2017] [Indexed: 12/24/2022]
Abstract
Studies of organismal and tissue biomechanics have clearly demonstrated that musculoskeletal design is strongly dependent on experienced loads, which can vary in the short term, as a result of growth during life history and during the evolution of animal body size. However, how animals actually perceive and make adjustments to their load-bearing musculoskeletal elements that accommodate variation in their body weight is poorly understood. We developed an experimental model system that can be used to start addressing these open questions, and uses hypergravity centrifugation to experimentally manipulate the loads experienced by Drosophila melanogaster We examined effects of this manipulation on leg muscle alternative splicing of the sarcomere gene troponin T (Dmel\up; Fbgn0004169, herein referred to by its synonym TnT), a process that was previously demonstrated to precisely correlate with quantitative variation in body weight in Lepidoptera and rat. In a similar fashion, hypergravity centrifugation caused fast (i.e. within 24 h) changes to fly leg muscle TnT alternative splicing that correlated with body weight variation across eight D. melanogaster lines. Hypergravity treatment also appeared to enhance leg muscle function, as centrifuged flies showed an increased negative geotaxis response and jump ability. Although the identity and location of the sensors and effectors involved remains unknown, our results provide further support for the existence of an evolutionarily conserved mechanism that translates signals that encode body weight into appropriate skeletal muscle molecular and functional responses.
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Affiliation(s)
- Rudolf J Schilder
- Department of Entomology, Pennsylvania State University, 501 Ag Sciences & Industries Building, University Park, PA 16802, USA .,Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA.,Department of Cellular & Molecular Physiology, Pennsylvania State University, 500 University Drive, Hershey, PA 17033, USA
| | - Megan Raynor
- Department of Biology, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA
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