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Jiang C, Xu H, Yang L, Liu J, Li Y, Takei K, Xu W. Neuromorphic antennal sensory system. Nat Commun 2024; 15:2109. [PMID: 38453967 PMCID: PMC10920631 DOI: 10.1038/s41467-024-46393-7] [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: 10/16/2023] [Accepted: 02/26/2024] [Indexed: 03/09/2024] Open
Abstract
Insect antennae facilitate the nuanced detection of vibrations and deflections, and the non-contact perception of magnetic or chemical stimuli, capabilities not found in mammalian skin. Here, we report a neuromorphic antennal sensory system that emulates the structural, functional, and neuronal characteristics of ant antennae. Our system comprises electronic antennae sensor with three-dimensional flexible structures that detects tactile and magnetic stimuli. The integration of artificial synaptic devices adsorbed with solution-processable MoS2 nanoflakes enables synaptic processing of sensory information. By emulating the architecture of receptor-neuron pathway, our system realizes hardware-level, spatiotemporal perception of tactile contact, surface pattern, and magnetic field (detection limits: 1.3 mN, 50 μm, 9.4 mT). Vibrotactile-perception tasks involving profile and texture classifications were accomplished with high accuracy (> 90%), surpassing human performance in "blind" tactile explorations. Magneto-perception tasks including magnetic navigation and touchless interaction were successfully completed. Our work represents a milestone for neuromorphic sensory systems and biomimetic perceptual intelligence.
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Affiliation(s)
- Chengpeng Jiang
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, College of Electronic Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin, China
- Shenzhen Research Institute of Nankai University, Shenzhen, China
| | - Honghuan Xu
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, College of Electronic Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin, China
- Shenzhen Research Institute of Nankai University, Shenzhen, China
| | - Lu Yang
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, College of Electronic Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin, China
- Shenzhen Research Institute of Nankai University, Shenzhen, China
| | - Jiaqi Liu
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, College of Electronic Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin, China
- Shenzhen Research Institute of Nankai University, Shenzhen, China
| | - Yue Li
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, College of Electronic Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin, China
- Shenzhen Research Institute of Nankai University, Shenzhen, China
| | - Kuniharu Takei
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan.
| | - Wentao Xu
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, College of Electronic Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin, China.
- Shenzhen Research Institute of Nankai University, Shenzhen, China.
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Kannegieser S, Kraft N, Haan A, Stöckl A. Visual guidance fine-tunes probing movements of an insect appendage. Proc Natl Acad Sci U S A 2024; 121:e2306937121. [PMID: 38285936 PMCID: PMC10861887 DOI: 10.1073/pnas.2306937121] [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: 04/28/2023] [Accepted: 12/13/2023] [Indexed: 01/31/2024] Open
Abstract
Visually guided reaching, a regular feature of human life, comprises an intricate neural control task. It includes identifying the target's position in 3D space, passing the representation to the motor system that controls the respective appendages, and adjusting ongoing movements using visual and proprioceptive feedback. Given the complexity of the neural control task, invertebrates, with their numerically constrained central nervous systems, are often considered incapable of this level of visuomotor guidance. Here, we provide mechanistic insights into visual appendage guidance in insects by studying the probing movements of the hummingbird hawkmoth's proboscis as they search for a flower's nectary. We show that visually guided proboscis movements fine-tune the coarse control provided by body movements in flight. By impairing the animals' view of their proboscis, we demonstrate that continuous visual feedback is required and actively sought out to guide this appendage. In doing so, we establish an insect model for the study of neural strategies underlying eye-appendage control in a simple nervous system.
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Affiliation(s)
- Sören Kannegieser
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum am Hubland, Würzburg97074, Germany
| | - Nadine Kraft
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum am Hubland, Würzburg97074, Germany
| | - Alexa Haan
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum am Hubland, Würzburg97074, Germany
| | - Anna Stöckl
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum am Hubland, Würzburg97074, Germany
- Department of Biology, University of Konstanz, Konstanz78464, Germany
- Zukunftskolleg, Universität Konstanz, Konstanz78464, Germany
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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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Homberg U, Kirchner M, Kowalewski K, Pitz V, Kinoshita M, Kern M, Seyfarth J. Comparative morphology of serotonin-immunoreactive neurons innervating the central complex in the brain of dicondylian insects. J Comp Neurol 2023. [PMID: 37478205 DOI: 10.1002/cne.25529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/28/2023] [Accepted: 07/08/2023] [Indexed: 07/23/2023]
Abstract
Serotonin (5-hydroxytryptamine) acts as a widespread neuromodulator in the nervous system of vertebrates and invertebrates. In insects, it promotes feeding, enhances olfactory sensitivity, modulates aggressive behavior, and, in the central complex of Drosophila, serves a role in sleep homeostasis. In addition to a role in sleep-wake regulation, the central complex has a prominent role in spatial orientation, goal-directed locomotion, and navigation vector memory. To further understand the role of serotonergic signaling in this brain area, we analyzed the distribution and identity of serotonin-immunoreactive neurons across a wide range of insect species. While one bilateral pair of tangential neurons innervating the central body was present in all species studied, a second type was labeled in all neopterans but not in dragonflies and firebrats. Both cell types show conserved major fiber trajectories but taxon-specific differences in dendritic targets outside the central body and axonal terminals in the central body, noduli, and lateral accessory lobes. In addition, numerous tangential neurons of the protocerebral bridge were labeled in all studied polyneopteran species except for Phasmatodea, but not in Holometabola. Lepidoptera and Diptera showed additional labeling of two bilateral pairs of neurons of a third type. The presence of serotonin in systems of columnar neurons apparently evolved independently in dragonflies and desert locusts. The data suggest distinct evolutionary changes in the composition of serotonin-immunolabeled neurons of the central complex and provides a promising basis for a phylogenetic study in a wider range of arthropod species.
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Affiliation(s)
- Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Michelle Kirchner
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Kevin Kowalewski
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Vanessa Pitz
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Michiyo Kinoshita
- Laboratory of Neuroethology, SOKENDAI, The Graduate University for Advanced Studies, Hayama, Japan
| | - Martina Kern
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Jutta Seyfarth
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
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5
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Römer D, Exl R, Roces F. Two feedback mechanisms involved in the control of leaf fragment size in leaf-cutting ants. J Exp Biol 2023; 226:jeb244246. [PMID: 37348454 PMCID: PMC10323230 DOI: 10.1242/jeb.244246] [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: 03/09/2022] [Accepted: 05/09/2023] [Indexed: 06/24/2023]
Abstract
Polymorphic leaf-cutting ants harvest leaf fragments that correlate in size with the workers' body size. When cutting, workers anchor their hind legs on the leaf edge and rotate, removing approximately semicircular fragments. Workers show behavioural plasticity and modify their leg extension while holding onto the leaf edge depending on, for instance, leaf toughness, cutting smaller fragments out of tough leaves. What sensory information workers use to control the cutting trajectory remains unknown. We investigated whether sensory information from both the leg contact with the leaf edge and from head movements underlies fragment size determination. In the laboratory, we recorded Atta sexdens workers cutting standardised ®Parafilm pseudoleaves of different thickness, and quantified cutting behaviour and body reach, i.e. the distance between the mandible and the anchored hind leg tarsus. Experimentally preventing contact with the leaf edge resulted in smaller fragments, evincing that workers control the cutting trajectory using information from the contact of the hind legs with the leaf edge. However, ants were able to cut fragments even when contact of all six legs with the edge was prevented, indicating the use of additional sensory information. Ablation of mechanosensory hairs at the neck joint alone did not influence fragment size determination, yet simultaneously preventing sensory feedback from both mechanosensory hairs and edge contact led to a loss of control over the cutting trajectory. Leaf-cutting ants, therefore, control their cutting trajectory using sensory information from both the leg contact with the leaf edge and the lateral bending of the head.
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Affiliation(s)
- Daniela Römer
- Department of Behavioural Physiology and Sociobiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Rebecca Exl
- Department of Behavioural Physiology and Sociobiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Flavio Roces
- Department of Behavioural Physiology and Sociobiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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Dürr V, Mesanovic A. Behavioural function and development of body-to-limb proportions and active movement ranges in three stick insect species. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:265-284. [PMID: 35986777 PMCID: PMC10006035 DOI: 10.1007/s00359-022-01564-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/27/2022] [Accepted: 08/02/2022] [Indexed: 11/30/2022]
Abstract
Overall body proportions and relative limb length are highly characteristic for most insect taxa. In case of the legs, limb length has mostly been discussed with regard to parameters of locomotor performance and, in particular cases, as an adaptation to environmental factors or to the mating system. Here, we compare three species of stick and leaf insects (Phasmatodea) that differ strongly in the length ratio between antennae and walking legs, with the antennae of Medauroidea extradentata being much shorter than its legs, nearly equal length of antennae and legs in Carausius morosus, and considerably longer antennae than front legs in Aretaon asperrimus. We show that that relative limb length is directly related to the near-range exploration effort, with complementary function of the antennae and front legs irrespective of their length ratio. Assuming that these inter-species differences hold for both sexes and all developmental stages, we further explore how relative limb length differs between sexes and how it changes throughout postembryonic development. We show that the pattern of limb-to-body proportions is species-characteristic despite sexual dimorphism, and find that the change in sexual dimorphism is strongest during the last two moults. Finally, we show that antennal growth rate is consistently higher than that of front legs, but differs categorically between the species investigated. Whereas antennal growth rate is constant in Carausius, the antennae grow exponentially in Medauroidea and with a sudden boost during the last moult in Aretaon.
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Affiliation(s)
- Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany.
- Center for Cognitive Interaction Technology, Bielefeld University, 33615, Bielefeld, Germany.
| | - Ago Mesanovic
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany
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7
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Wang Y, Othayoth R, Li C. Cockroaches adjust body and appendages to traverse cluttered large obstacles. J Exp Biol 2022; 225:275496. [PMID: 35502788 DOI: 10.1242/jeb.243605] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 04/25/2022] [Indexed: 11/20/2022]
Abstract
To traverse complex terrain, animals often transition between locomotor modes. It is well-known that locomotor transitions can be induced by switching in neural control circuits or driven by a need to minimize metabolic energetic cost. Recent work discovered that locomotor transitions in complex 3-D terrain cluttered with large obstacles can emerge from physical interaction with the environment controlled by the nervous system. For example, to traverse cluttered, stiff grass-like beams, the discoid cockroach often transitions from using a strenuous pitch mode pushing across to using a less strenuous roll mode rolling into and through the gaps, and this transition requires overcoming a potential energy barrier. Previous robotic physical modeling demonstrated that kinetic energy fluctuation of body oscillation from self-propulsion can help overcome the barrier and facilitate this transition. However, the animal was observed to transition even when the barrier still exceeded kinetic energy fluctuation. Here, we further studied whether and how the cockroach makes active adjustments to facilitate this transition to traverse cluttered beams. The animal repeatedly flexed its head and abdomen, reduced hind leg sprawl, and depressed one hind leg and elevated the other during the pitch-to-roll transition, which were absent when running on a flat ground. Using a refined potential energy landscape with additional degrees of freedom to model these adjustments, we found that head flexion did not substantially reduce the transition barrier, whereas leg sprawl reduction did so dramatically. We speculate that head flexion is for sensing the terrain to guide the transition via sensory feedback control.
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Affiliation(s)
- Yaqing Wang
- Department of Mechanical Engineering, Johns Hopkins University, USA
| | - Ratan Othayoth
- Department of Mechanical Engineering, Johns Hopkins University, USA
| | - Chen Li
- Department of Mechanical Engineering, Johns Hopkins University, USA
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Berendes V, Dürr V. Active tactile exploration and tactually induced turning in tethered walking stick insects. J Exp Biol 2022; 225:274336. [PMID: 35142361 DOI: 10.1242/jeb.243190] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 01/20/2022] [Indexed: 11/20/2022]
Abstract
Many animals use their tactile sense for active exploration and tactually guided behaviors like near-range orientation. In insects, tactile sensing is often intimately linked to locomotion, resulting in the orchestration of several concurrent active movements, including turning of the entire body, rotation of the head, and searching or sampling movements of the antennae. The present study aims at linking the sequence of tactile contact events to associated changes of all three kinds of these active movements (body, head and antennae). To do so, we chose the Indian stick insect Carausius morosus, a common organism to study sensory control of locomotion. Methodologically, we combined recordings of walking speed, heading, whole-body kinematics and antennal contact sequences during stationary, tethered walking and controlled presentation of an "artificial twig" for tactile exploration. Our results show that object presentation episodes as brief as five seconds are sufficient to allow for a systematic investigation of tactually-induced turning behavior in walking stick insects. Animals began antennating the artificial twig within 0.5 s. and altered the beating-fields of both antennae in a position-dependent manner. This change was mainly carried by a systematic shift of the head-scape joint movement and accompanied by associated changes in contact likelihood, contact location and sampling direction of the antennae. The turning tendency of the insect also depended on stimulus position, whereas the active, rhythmic head rotation remained un-affected by stimulus presentation. We conclude that the azimuth of contact location is a key parameter of active tactile exploration and tactually-induced turning in stick insects.
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Affiliation(s)
- Volker Berendes
- Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Volker Dürr
- Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany.,Center for Cognitive Interaction Technology, Bielefeld University, Bielefeld, Germany
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9
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Jaske B, Lepreux G, Dürr V. Input of hair field afferents to a descending interneuron. J Neurophysiol 2021; 126:398-412. [PMID: 34161139 DOI: 10.1152/jn.00169.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In insects the tactile sense is important for near-range orientation and is involved in various behaviors. Nocturnal insects, such as the stick insect Carausius morosus, continuously explore their surroundings by actively moving their antennae when walking. Upon antennal contact with objects, stick insects show a targeted front-leg movement. As this reaction occurs within 40 ms, descending transfer of information from the brain to the thorax needs to be fast. So far, a number of descending interneurons have been described that may be involved in this reach-to-grasp behavior. One of these is the contralateral ON-type velocity-sensitive neuron (cONv). cONv was found to encode antennal joint-angle velocity during passive movement. Here, we characterize the transient response properties of cONv, including its dependence on joint angle range and direction. As antennal hair field afferent terminals were shown to arborize close to cONv dendrites, we test whether antennal hair fields contribute to the joint-angle velocity encoding of cONv. To do so, we conducted bilateral extracellular recordings of both cONv interneurons per animal before and after hair field ablations. Our results show that cONv responses are highly transient, with velocity-dependent differences in delay and response magnitude. As yet, the steady state activity level was maintained until the stop of antennal movement, irrespective of movement velocity. Hair field ablation caused a moderate but significant reduction of movement-induced cONv firing rate by up to 40%. We conclude that antennal proprioceptive hair fields contribute to the velocity-tuning of cONv, though further antennal mechanoreceptors must be involved, too.NEW & NOTEWORTHY Active tactile exploration and tactually induced behaviors are important for many animals. They require descending information transfer about tactile sensor movement to thoracic networks. Here, we investigate response properties and afferent input to the identified descending interneuron cONv in stick insects. cONv may be involved in tactually induced reach-to-grasp movements. We show that cONv response delay, transient and steady state are velocity-dependent and that antennal proprioceptive hair fields contribute to the velocity encoding of cONv.
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Affiliation(s)
- Bianca Jaske
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Gaëtan Lepreux
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany.,Center of Cognitive Interaction Technology, Bielefeld University, Bielefeld, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany.,Center of Cognitive Interaction Technology, Bielefeld University, Bielefeld, Germany
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David I, Ayali A. From Motor-Output to Connectivity: An In-Depth Study of in-vitro Rhythmic Patterns in the Cockroach Periplaneta americana. FRONTIERS IN INSECT SCIENCE 2021; 1:655933. [PMID: 38468881 PMCID: PMC10926548 DOI: 10.3389/finsc.2021.655933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/22/2021] [Indexed: 03/13/2024]
Abstract
The cockroach is an established model in the study of locomotion control. While previous work has offered important insights into the interplay among brain commands, thoracic central pattern generators, and the sensory feedback that shapes their motor output, there remains a need for a detailed description of the central pattern generators' motor output and their underlying connectivity scheme. To this end, we monitored pilocarpine-induced activity of levator and depressor motoneurons in two types of novel in-vitro cockroach preparations: isolated thoracic ganglia and a whole-chain preparation comprising the thoracic ganglia and the subesophageal ganglion. Our data analyses focused on the motoneuron firing patterns and the coordination among motoneuron types in the network. The burstiness and rhythmicity of the motoneurons were monitored, and phase relations, coherence, coupling strength, and frequency-dependent variability were analyzed. These parameters were all measured and compared among network units both within each preparation and among the preparations. Here, we report differences among the isolated ganglia, including asymmetries in phase and coupling strength, which indicate that they are wired to serve different functions. We also describe the intrinsic default gait and a frequency-dependent coordination. The depressor motoneurons showed mostly similar characteristics throughout the network regardless of interganglia connectivity; whereas the characteristics of the levator motoneurons activity were mostly ganglion-dependent, and influenced by the presence of interganglia connectivity. Asymmetries were also found between the anterior and posterior homolog parts of the thoracic network, as well as between ascending and descending connections. Our analyses further discover a frequency-dependent inversion of the interganglia coordination from alternations between ipsilateral homolog oscillators to simultaneous activity. We present a detailed scheme of the network couplings, formulate coupling rules, and review a previously suggested model of connectivity in light of our new findings. Our data support the notion that the inter-hemiganglia coordination derives from the levator networks and their coupling with local depressor interneurons. Our findings also support a dominant role of the metathoracic ganglion and its ascending output in governing the anterior ganglia motor output during locomotion in the behaving animal.
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Affiliation(s)
- Izhak David
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - 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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11
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Deora T, Ahmed MA, Daniel TL, Brunton BW. Tactile active sensing in an insect plant pollinator. J Exp Biol 2021; 224:jeb.239442. [PMID: 33441388 DOI: 10.1242/jeb.239442] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/03/2021] [Indexed: 11/20/2022]
Abstract
The interaction between insects and the flowers they pollinate has driven the evolutionary diversity of both insects and flowering plants, two groups with the most numerous species on Earth. Insects use vision and olfaction to localize host plants, but we know relatively little about how they find the tiny nectary opening in the flower, which can be well beyond their visual resolution. Especially when vision is limited, touch becomes crucial in successful insect-plant pollination interactions. Here, we studied the remarkable feeding behavior of crepuscular hawkmoths Manduca sexta, which use their long, actively controlled, proboscis to expertly explore flower-like surfaces. Using machine vision and 3D-printed artificial flower-like feeders, we revealed a novel behavior that shows moths actively probe surfaces, sweeping their proboscis from the feeder edge to its center repeatedly until they locate the nectary opening. Moreover, naive moths rapidly learn to exploit these flowers, and they adopt a tactile search strategy to more directly locate the nectary opening in as few as three to five consecutive visits. Our results highlight the proboscis as a unique active sensory structure and emphasize the central role of touch in nectar foraging insect-plant pollinator interactions.
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Affiliation(s)
- Tanvi Deora
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Mahad A Ahmed
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Thomas L Daniel
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Bing W Brunton
- Department of Biology, University of Washington, Seattle, WA 98195, USA
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12
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Clifton GT, Holway D, Gravish N. Vision does not impact walking performance in Argentine ants. ACTA ACUST UNITED AC 2020; 223:223/20/jeb228460. [PMID: 33067354 DOI: 10.1242/jeb.228460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/10/2020] [Indexed: 11/20/2022]
Abstract
Many walking insects use vision for long-distance navigation, but the influence of vision on rapid walking performance that requires close-range obstacle detection and directing the limbs towards stable footholds remains largely untested. We compared Argentine ant (Linepithema humile) workers in light versus darkness while traversing flat and uneven terrain. In darkness, ants reduced flat-ground walking speeds by only 5%. Similarly, the approach speed and time to cross a step obstacle were not significantly affected by lack of lighting. To determine whether tactile sensing might compensate for vision loss, we tracked antennal motion and observed shifts in spatiotemporal activity as a result of terrain structure but not illumination. Together, these findings suggest that vision does not impact walking performance in Argentine ant workers. Our results help contextualize eye variation across ants, including subterranean, nocturnal and eyeless species that walk in complete darkness. More broadly, our findings highlight the importance of integrating vision, proprioception and tactile sensing for robust locomotion in unstructured environments.
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Affiliation(s)
- Glenna T Clifton
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA .,Department of Biology, University of Portland, Portland, OR 97203, USA
| | - David Holway
- Division of Biological Science, Section of Ecology, Behavior and Evolution, University of California, San Diego , La Jolla, CA 92093, USA
| | - Nicholas Gravish
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
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13
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Lepreux G, Haupt SS, Dürr V. Bimodal modulation of background activity in an identified descending interneuron. J Neurophysiol 2019; 122:2316-2330. [DOI: 10.1152/jn.00864.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the absence of any obvious input, sensory neurons and interneurons can display resting or spontaneous activity. This is often regarded as noise and removed through trial averaging, although it may reflect history-dependent modulation of tuning or fidelity and, thus, be of functional relevance to downstream interneurons. We investigated the history dependence of spontaneous activity in a pair of identified, bimodal descending interneurons of the stick insect, called contralateral ON-type velocity-sensitive interneurons (cONv). The bilateral pair of cONv conveys antennal mechanosensory information to the thoracic ganglia, where it arborizes in regions containing locomotor networks. Each cONv encodes the movement velocity of the contralateral antenna, but also substrate vibration as induced by discrete tapping events. Moreover, cONv display highly fluctuating spontaneous activity that can reach rates similar to those during antennal movement at moderate velocities. Hence, cONv offer a unique opportunity to study history-dependent effects on spontaneous activity and, thus, encoding fidelity in two modalities. In this work, we studied unimodal and cross-modal effects as well as unilateral and bilateral effects, using bilateral recordings of both cONv neurons, while moving one antenna and/or delivering taps to induce substrate vibration. Tapping could reduce spontaneous activity of both neurons, whereas antennal movement reduced spontaneous activity of the contralateral cONv neuron only. Combination of both modalities showed a cooperative effect for some parameter constellations, suggesting bimodal enhancement. Since both stimulus modalities could cause a reduction of spontaneous activity at stimulus intensities occurring during natural locomotion, we conclude that this should enhance neuronal response fidelity during locomotion. NEW & NOTEWORTHY The spontaneous activity in a pair of identified, descending insect interneurons is reduced depending on stimulus history. At rest, spontaneous activity levels are correlated in both interneurons, indicating a common drive from background activity. Whereas taps on the substrate affect both interneurons, antennal movement affects the contralateral interneuron only. Cross-modal interaction occurs, too. Since spontaneous activity is reduced at stimulus intensities encountered during natural locomotion, the mechanism could enhance neuronal response fidelity during locomotion.
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Affiliation(s)
- Gaëtan Lepreux
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology – Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Stephan Shuichi Haupt
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology – Center of Excellence, Bielefeld University, Bielefeld, Germany
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14
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Büscher TH, Gorb SN. Complementary effect of attachment devices in stick insects (Phasmatodea). ACTA ACUST UNITED AC 2019; 222:jeb.209833. [PMID: 31727762 DOI: 10.1242/jeb.209833] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/06/2019] [Indexed: 11/20/2022]
Abstract
Stick insects are well adapted in their locomotion to various surfaces and topographies of natural substrates. Single pad measurements characterised the pretarsal arolia of these insects as shear-sensitive adhesive pads and the tarsal euplantulae as load-sensitive friction pads. Different attachment microstructures on the euplantulae reveal an adaptation of smooth euplantulae to smooth surfaces and nubby eupantulae to a broader range of surface roughness. However, how different attachment pads and claws work in concert and how strong the contribution of different structures is to the overall attachment performance remains unclear. We therefore assessed combinatory effects in the attachment system of two stick insect species with different types of euplantular microstructures by analysing their usage in various posture situations and the performance on different levels of substrate roughness. For comparison, we provide attachment force data of the whole attachment system. The combination of claws, arolia and euplantulae provides mechanical interlocking on rough surfaces, adhesion and friction on smooth surfaces in different directions, and facilitates attachment on different inclines and on a broad range of surface roughness, with the least performance in the range 0.3-1.0 µm. On smooth surfaces, stick insects use arolia always, but employ euplantulae if the body weight can generate load on them (upright, wall). On structured surfaces, claws enable mechanical interlocking at roughnesses higher than 12 µm. On less-structured surfaces, the attachment strength depends on the use of pads and, corroborating earlier studies, favours smooth pads on smooth surfaces, but nubby euplantulae on micro-rough surfaces.
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Affiliation(s)
- Thies H Büscher
- Department of Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
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15
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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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16
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Dallmann CJ, Dürr V, Schmitz J. Motor control of an insect leg during level and incline walking. ACTA ACUST UNITED AC 2019; 222:222/7/jeb188748. [PMID: 30944163 DOI: 10.1242/jeb.188748] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 03/04/2019] [Indexed: 01/16/2023]
Abstract
During walking, the leg motor system must continually adjust to changes in mechanical conditions, such as the inclination of the ground. To understand the underlying control, it is important to know how changes in leg muscle activity relate to leg kinematics (movements) and leg dynamics (forces, torques). Here, we studied these parameters in hindlegs of stick insects (Carausius morosus) during level and uphill/downhill (±45 deg) walking, using a combination of electromyography, 3D motion capture and ground reaction force measurements. We find that some kinematic parameters including leg joint angles and body height vary across walking conditions. However, kinematics vary little compared with dynamics: horizontal leg forces and torques at the thorax-coxa joint (leg protraction/retraction) and femur-tibia joint (leg flexion/extension) tend to be stronger during uphill walking and are reversed in sign during downhill walking. At the thorax-coxa joint, the different mechanical demands are met by adjustments in the timing and magnitude of antagonistic muscle activity. Adjustments occur primarily in the first half of stance after the touch-down of the leg. When insects transition from level to incline walking, the characteristic adjustments in muscle activity occur with the first step of the leg on the incline, but not in anticipation. Together, these findings indicate that stick insects adjust leg muscle activity on a step-by-step basis so as to maintain a similar kinematic pattern under different mechanical demands. The underlying control might rely primarily on feedback from leg proprioceptors signaling leg position and movement.
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Affiliation(s)
- Chris J Dallmann
- Department of Biological Cybernetics, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany .,Cognitive Interaction Technology Center of Excellence, Bielefeld University, Inspiration 1, 33619 Bielefeld, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.,Cognitive Interaction Technology Center of Excellence, Bielefeld University, Inspiration 1, 33619 Bielefeld, Germany
| | - Josef Schmitz
- Department of Biological Cybernetics, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany .,Cognitive Interaction Technology Center of Excellence, Bielefeld University, Inspiration 1, 33619 Bielefeld, Germany
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17
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Dürr V, Schilling M. Transfer of Spatial Contact Information Among Limbs and the Notion of Peripersonal Space in Insects. Front Comput Neurosci 2018; 12:101. [PMID: 30618693 PMCID: PMC6305554 DOI: 10.3389/fncom.2018.00101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/03/2018] [Indexed: 11/13/2022] Open
Abstract
Internal representation of far-range space in insects is well established, as it is necessary for navigation behavior. Although it is likely that insects also have an internal representation of near-range space, the behavioral evidence for the latter is much less evident. Here, we estimate the size and shape of the spatial equivalent of a near-range representation that is constituted by somatosensory sampling events. To do so, we use a large set of experimental whole-body motion capture data on unrestrained walking, climbing and searching behavior in stick insects of the species Carausius morosus to delineate ‘action volumes’ and ‘contact volumes’ for both antennae and all six legs. As these volumes are derived from recorded sampling events, they comprise a volume equivalent to a representation of coinciding somatosensory and motor activity. Accordingly, we define this volume as the peripersonal space of an insect. It is of immediate behavioral relevance, because it comprises all potential external object locations within the action range of the body. In a next step, we introduce the notion of an affordance space as that part of peripersonal space within which contact-induced spatial estimates lie within the action ranges of more than one limb. Because the action volumes of limbs overlap in this affordance space, spatial information from one limb can be used to control the movement of another limb. Thus, it gives rise to an affordance as known for contact-induced reaching movements and spatial coordination of footfall patterns in stick insects. Finally, we probe the computational properties of the experimentally derived affordance space for pairs of neighboring legs. This is done by use of artificial neural networks that map the posture of one leg into a target posture of another leg with identical foot position.
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Affiliation(s)
- Volker Dürr
- Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany.,Cluster of Excellence Cognitive Interactive Technology (CITEC), Bielefeld University, Bielefeld, Germany
| | - Malte Schilling
- Cluster of Excellence Cognitive Interactive Technology (CITEC), Bielefeld University, Bielefeld, Germany
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18
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Sant HH, Sane SP. The mechanosensory-motor apparatus of antennae in the Oleander hawk moth (Daphnis nerii, Lepidoptera). J Comp Neurol 2018; 526:2215-2230. [PMID: 29907958 DOI: 10.1002/cne.24477] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/05/2018] [Accepted: 04/23/2018] [Indexed: 11/06/2022]
Abstract
Insect antennae are sensory organs of great importance because they can sense diverse environmental stimuli. In addition to serving as primary olfactory organs of insects, antennae also sense a wide variety of mechanosensory stimuli, ranging from low-frequency airflow or gravity cues to high-frequency antennal vibrations due to sound, flight or touch. The basal segments of the antennae house multiple types of mechanosensory structures that prominently include the sensory hair plates, or Böhm's bristles, which measure the gross extent of antennal movement, and a ring of highly sensitive scolopidial neurons, collectively called the Johnston's organs, which record subtle flagellar vibrations. To fulfill their multifunctional mechanosensory role, the antennae of insects must actively move thereby enhancing their ability to sense various cues in the surrounding environment. This tight coupling between antennal mechanosensory function and antennal movements means that the underlying mechanosensory-motor apparatus constitutes a highly tuned feedback-controlled system. Our study aims to explore how the sensory and motor components of this system are configured to enable such functional versatility. We describe antennal mechanosensory neurons, their central projections in the brain relative to antennal motor neurons and the internal morphology of various antennal muscles that actuate the basal segments of the antenna. We studied these in the Oleander hawk moth (Daphnis nerii) using a combination of techniques such as neural dye fills, confocal microscopy, scanning electron microscopy and X-ray tomography. Our study thus provides a detailed anatomical picture of the antennal mechanosensory-motor apparatus, which in turn provides key insights into its multifunctional role.
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Affiliation(s)
- Harshada H Sant
- National Centre for Biological Sciences, TIFR, Bangalore, Karnataka, 560065, India.,Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Sanjay P Sane
- National Centre for Biological Sciences, TIFR, Bangalore, Karnataka, 560065, India
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19
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Goldammer J, Dürr V. Proprioceptive input to a descending pathway conveying antennal postural information: Terminal organisation of antennal hair field afferents. ARTHROPOD STRUCTURE & DEVELOPMENT 2018; 47:465-481. [PMID: 30076912 DOI: 10.1016/j.asd.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/27/2018] [Accepted: 07/08/2018] [Indexed: 06/08/2023]
Abstract
Like several other arthropod species, stick insects use their antennae for tactile exploration of the near-range environment and for spatial localisation of touched objects. More specifically, Carausius morosus continuously moves its antennae during locomotion and reliably responds to antennal contact events with directed movements of a front leg. Here we investigate the afferent projection patterns of antennal hair fields (aHF), proprioceptors known to encode antennal posture and movement, and to be involved in antennal movement control. We show that afferents of all seven aHF of C. morosus have terminal arborisations in the dorsal lobe (DL) of the cerebral (=supraoesophageal) ganglion, and descending collaterals that terminate in a characteristic part of the gnathal (=suboesophageal) ganglion. Despite differences of functional roles among aHF, terminal arborisation patterns show no topological arrangement according to segment specificity or direction of movement. In the DL, antennal motoneuron neurites show arborizations in proximity to aHF afferent terminals. Despite the morphological similarity of single mechanoreceptors of aHF and adjacent tactile hairs on the pedicel and flagellum, we find a clear separation of proprioceptive and exteroceptive mechanosensory neuropils in the cerebral ganglion. Moreover, we also find this functional separation in the gnathal ganglion.
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Affiliation(s)
- Jens Goldammer
- Animal Physiology and Neurobiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany.
| | - Volker Dürr
- Dept. Biological Cybernetics, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
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20
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Rajabi H, Shafiei A, Darvizeh A, Gorb SN, Dürr V, Dirks JH. Both stiff and compliant: morphological and biomechanical adaptations of stick insect antennae for tactile exploration. J R Soc Interface 2018; 15:rsif.2018.0246. [PMID: 30045891 DOI: 10.1098/rsif.2018.0246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 07/04/2018] [Indexed: 11/12/2022] Open
Abstract
Active tactile exploration behaviour is constrained to a large extent by the morphological and biomechanical properties of the animal's somatosensory system. In the model organism Carausius morosus, the main tactile sensory organs are long, thin, seemingly delicate, but very robust antennae. Previous studies have shown that these antennae are compliant under contact, yet stiff enough to maintain a straight shape during active exploration. Overcritical damping of the flagellum, on the other hand, allows for a rapid return to the straight shape after release of contact. Which roles do the morphological and biomechanical adaptations of the flagellum play in determining these special mechanical properties? To investigate this question, we used a combination of biomechanical experiments and numerical modelling. A set of four finite-element (FE) model variants was derived to investigate the effect of the distinct geometrical and material properties of the flagellum on its static (bending) and dynamic (damping) characteristics. The results of our numerical simulations show that the tapered shape of the flagellum had the strongest influence on its static biomechanical behaviour. The annulated structure and thickness gradient affected the deformability of the flagellum to a lesser degree. The inner endocuticle layer of the flagellum was confirmed to be essential for explaining the strongly damped return behaviour of the antenna. By highlighting the significance of two out of the four main structural features of the insect flagellum, our study provides a basis for mechanical design of biomimetic touch sensors tuned to become maximally flexible while quickly resuming a straight shape after contact.
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Affiliation(s)
- H Rajabi
- Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Kiel, Germany
| | - A Shafiei
- Department of Mechanical Engineering, University of Guilan, Rasht, Iran.,Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - A Darvizeh
- Department of Mechanical Engineering, Anzali Branch, Islamic Azad University, Bandar Anzali, Iran
| | - S N Gorb
- Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Kiel, Germany
| | - V Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
| | - J-H Dirks
- Max-Planck-Institute for Intelligent Systems, Stuttgart, Germany.,Biomimetics-Innovation-Centre, Hochschule Bremen-City University of Applied Sciences, Bremen, Germany
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21
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Motor flexibility in insects: adaptive coordination of limbs in locomotion and near-range exploration. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2412-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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22
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Tóth TI, Berg E, Daun S. Modeling search movements of an insect's front leg. Physiol Rep 2017; 5:5/22/e13489. [PMID: 29146863 PMCID: PMC5704076 DOI: 10.14814/phy2.13489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/03/2017] [Accepted: 10/10/2017] [Indexed: 11/24/2022] Open
Abstract
Beside locomotion, search movements are another important type of motor activity of insects. They are very often performed by the front legs of the animals. They consist of cyclic stereotypical leg movements that can be modified by sensory signals. The details of the local organization of these movements have however not yet been studied. In this paper, we, using an appropriate variant of our existing one-leg model, present a scheme of how these searching movements might be organized and performed on the level of local neuromuscular control networks. In the simulations with the model, we attempted to mimic the experimental results by Berg et al. (J. Exp. Biol. 216:1064-1074, 2013) in which an obstacle was put in the way of the search movements of the front leg for a very short while, and then the recovery to the usual search movements was observed and analyzed. Our simulation results suggest that the recruitment of the fast levator and depressor muscles play a crucial part in resuming the search movements after removal of the obstacle. The interplay between the levator and depressor, and the extensor and flexor local control networks can, according to the model, bring about a large variety of search movements upon removal of the obstacle. A number of these movements are comparable with those seen in the experiments.
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Affiliation(s)
- Tibor I Tóth
- Heisenberg Research Group of Computational Neuroscience - Modeling Neuronal Network Function, University of Cologne, Cologne, Germany
| | - Eva Berg
- Karolinska Institute, University of Stockholm, Stockholm, Sweden
| | - Silvia Daun
- Heisenberg Research Group of Computational Neuroscience - Modeling Neuronal Network Function, University of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Jülich, Germany
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23
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Rosa ME, Barta Z, Fülöp A, Székely T, Kosztolányi A. The effects of adult sex ratio and density on parental care in Lethrus apterus (Coleoptera, Geotrupidae). Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.07.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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Mantziaris C, Bockemühl T, Holmes P, Borgmann A, Daun S, Büschges A. Intra- and intersegmental influences among central pattern generating networks in the walking system of the stick insect. J Neurophysiol 2017; 118:2296-2310. [PMID: 28724783 DOI: 10.1152/jn.00321.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/05/2017] [Accepted: 07/17/2017] [Indexed: 11/22/2022] Open
Abstract
To efficiently move around, animals need to coordinate their limbs. Proper, context-dependent coupling among the neural networks underlying leg movement is necessary for generating intersegmental coordination. In the slow-walking stick insect, local sensory information is very important for shaping coordination. However, central coupling mechanisms among segmental central pattern generators (CPGs) may also contribute to this. Here, we analyzed the interactions between contralateral networks that drive the depressor trochanteris muscle of the legs in both isolated and interconnected deafferented thoracic ganglia of the stick insect on application of pilocarpine, a muscarinic acetylcholine receptor agonist. Our results show that depressor CPG activity is only weakly coupled between all segments. Intrasegmental phase relationships differ between the three isolated ganglia, and they are modified and stabilized when ganglia are interconnected. However, the coordination patterns that emerge do not resemble those observed during walking. Our findings are in line with recent studies and highlight the influence of sensory input on coordination in slowly walking insects. Finally, as a direct interaction between depressor CPG networks and contralateral motoneurons could not be observed, we hypothesize that coupling is based on interactions at the level of CPG interneurons.NEW & NOTEWORTHY Maintaining functional interleg coordination is vitally important as animals locomote through changing environments. The relative importance of central mechanisms vs. sensory feedback in this process is not well understood. We analyzed coordination among the neural networks generating leg movements in stick insect preparations lacking phasic sensory feedback. Under these conditions, the networks governing different legs were only weakly coupled. In stick insect, central connections alone are thus insufficient to produce the leg coordination observed behaviorally.
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Affiliation(s)
- Charalampos Mantziaris
- Department of Animal Physiology, Zoological Institute, Biocenter, University of Cologne, Cologne, Germany
| | - Till Bockemühl
- Department of Animal Physiology, Zoological Institute, Biocenter, University of Cologne, Cologne, Germany
| | - Philip Holmes
- Department of Mechanical and Aerospace Engineering, Program in Applied and Computational Mathematics and Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey; and
| | - Anke Borgmann
- Department of Animal Physiology, Zoological Institute, Biocenter, University of Cologne, Cologne, Germany
| | - Silvia Daun
- Department of Animal Physiology, Zoological Institute, Biocenter, University of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine (INM-3), Forschungszentrum Jülich, Jülich, Germany
| | - Ansgar Büschges
- Department of Animal Physiology, Zoological Institute, Biocenter, University of Cologne, Cologne, Germany;
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25
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Schilling M, Cruse H. ReaCog, a Minimal Cognitive Controller Based on Recruitment of Reactive Systems. Front Neurorobot 2017; 11:3. [PMID: 28194106 PMCID: PMC5276858 DOI: 10.3389/fnbot.2017.00003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 01/11/2017] [Indexed: 11/13/2022] Open
Abstract
It has often been stated that for a neuronal system to become a cognitive one, it has to be large enough. In contrast, we argue that a basic property of a cognitive system, namely the ability to plan ahead, can already be fulfilled by small neuronal systems. As a proof of concept, we propose an artificial neural network, termed reaCog, that, first, is able to deal with a specific domain of behavior (six-legged-walking). Second, we show how a minor expansion of this system enables the system to plan ahead and deploy existing behavioral elements in novel contexts in order to solve current problems. To this end, the system invents new solutions that are not possible for the reactive network. Rather these solutions result from new combinations of given memory elements. This faculty does not rely on a dedicated system being more or less independent of the reactive basis, but results from exploitation of the reactive basis by recruiting the lower-level control structures in a way that motor planning becomes possible as an internal simulation relying on internal representation being grounded in embodied experiences.
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Affiliation(s)
- Malte Schilling
- Center of Excellence Cognitive Interaction Technology, Bielefeld University Bielefeld, Germany
| | - Holk Cruse
- Department of Biological Cybernetics and Theoretical Biology, Bielefeld University Bielefeld, Germany
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Haberkern H, Hedwig B. Behavioural integration of auditory and antennal stimulation during phonotaxis in the field cricket Gryllus bimaculatus. J Exp Biol 2016; 219:3575-3586. [PMID: 27609761 PMCID: PMC5117196 DOI: 10.1242/jeb.141606] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/30/2016] [Indexed: 11/20/2022]
Abstract
Animals need to flexibly respond to stimuli from their environment without compromising behavioural consistency. For example, female crickets orienting toward a conspecific male's calling song in search of a mating partner need to stay responsive to other signals that provide information about obstacles and predators. Here, we investigate how spontaneously walking crickets and crickets engaging in acoustically guided goal-directed navigation, i.e. phonotaxis, respond to mechanosensory stimuli detected by their long antennae. We monitored walking behaviour of female crickets on a trackball during lateral antennal stimulation, which was achieved by moving a wire mesh transiently into reach of one antenna. During antennal stimulation alone, females reduced their walking speed, oriented toward the object and actively explored it with antennal movements. Additionally, some crickets initially turned away from the approaching object. Females responded in a similar way when the antennal stimulus was presented during ongoing phonotaxis: forward velocity was reduced and phonotactic steering was suppressed while the females turned toward and explored the object. Further, rapid steering bouts to individual chirps, typical for female phonotaxis, no longer occurred. Our data reveal that in this experimental situation, antennal stimulation overrides phonotaxis for extended time periods. Phonotaxis in natural environments, which require the integration of multiple sensory cues, may therefore be more variable than phonotaxis measured under ideal laboratory conditions. Combining this new behavioural paradigm with neurophysiological methods will show where the sensory-motor integration of antennal and acoustic stimulation occurs and how this is achieved on a mechanistic level.
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Affiliation(s)
- Hannah Haberkern
- Department of Zoology, University of Cambridge, Downing St, Cambridge CB2 3EJ, UK
- Howard Hughes Medical Institute, Janelia Farm Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Berthold Hedwig
- Department of Zoology, University of Cambridge, Downing St, Cambridge CB2 3EJ, UK
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Grinke E, Tetzlaff C, Wörgötter F, Manoonpong P. Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot. Front Neurorobot 2015; 9:11. [PMID: 26528176 PMCID: PMC4602151 DOI: 10.3389/fnbot.2015.00011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 09/22/2015] [Indexed: 11/27/2022] Open
Abstract
Walking animals, like insects, with little neural computing can effectively perform complex behaviors. For example, they can walk around their environment, escape from corners/deadlocks, and avoid or climb over obstacles. While performing all these behaviors, they can also adapt their movements to deal with an unknown situation. As a consequence, they successfully navigate through their complex environment. The versatile and adaptive abilities are the result of an integration of several ingredients embedded in their sensorimotor loop. Biological studies reveal that the ingredients include neural dynamics, plasticity, sensory feedback, and biomechanics. Generating such versatile and adaptive behaviors for a many degrees-of-freedom (DOFs) walking robot is a challenging task. Thus, in this study, we present a bio-inspired approach to solve this task. Specifically, the approach combines neural mechanisms with plasticity, exteroceptive sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent neural network consisting of two fully connected neurons. Online correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors) in the network to generate different turning angles with short-term memory for a walking robot. The turning information is transmitted as descending steering signals to the neural locomotion control which translates the signals into motor actions. As a result, the robot can walk around and adapt its turning angle for avoiding obstacles in different situations. The adaptation also enables the robot to effectively escape from sharp corners or deadlocks. Using backbone joint control embedded in the the locomotion control allows the robot to climb over small obstacles. Consequently, it can successfully explore and navigate in complex environments. We firstly tested our approach on a physical simulation environment and then applied it to our real biomechanical walking robot AMOSII with 19 DOFs to adaptively avoid obstacles and navigate in the real world.
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Affiliation(s)
- Eduard Grinke
- Bernstein Center for Computational Neuroscience, Third Institute of Physics, Georg-August-Universität Göttingen Göttingen, Germany
| | - Christian Tetzlaff
- Bernstein Center for Computational Neuroscience, Third Institute of Physics, Georg-August-Universität Göttingen Göttingen, Germany ; Department of Neurobiology, Weizmann Institute of Science Rehovot, Israel
| | - Florentin Wörgötter
- Bernstein Center for Computational Neuroscience, Third Institute of Physics, Georg-August-Universität Göttingen Göttingen, Germany
| | - Poramate Manoonpong
- Embodied AI and Neurorobotics Lab, Center for BioRobotics, The Mærsk Mc-Kinney Møller Institute, University of Southern Denmark Odense M, Denmark
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Harischandra N, Krause AF, Dürr V. Stable phase-shift despite quasi-rhythmic movements: a CPG-driven dynamic model of active tactile exploration in an insect. Front Comput Neurosci 2015; 9:107. [PMID: 26347644 PMCID: PMC4543877 DOI: 10.3389/fncom.2015.00107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/06/2015] [Indexed: 01/07/2023] Open
Abstract
An essential component of autonomous and flexible behavior in animals is active exploration of the environment, allowing for perception-guided planning and control of actions. An important sensory system involved is active touch. Here, we introduce a general modeling framework of Central Pattern Generators (CPGs) for movement generation in active tactile exploration behavior. The CPG consists of two network levels: (i) phase-coupled Hopf oscillators for rhythm generation, and (ii) pattern formation networks for capturing the frequency and phase characteristics of individual joint oscillations. The model captured the natural, quasi-rhythmic joint kinematics as observed in coordinated antennal movements of walking stick insects. Moreover, it successfully produced tactile exploration behavior on a three-dimensional skeletal model of the insect antennal system with physically realistic parameters. The effect of proprioceptor ablations could be simulated by changing the amplitude and offset parameters of the joint oscillators, only. As in the animal, the movement of both antennal joints was coupled with a stable phase difference, despite the quasi-rhythmicity of the joint angle time courses. We found that the phase-lead of the distal scape-pedicel (SP) joint relative to the proximal head-scape (HS) joint was essential for producing the natural tactile exploration behavior and, thus, for tactile efficiency. For realistic movement patterns, the phase-lead could vary within a limited range of 10–30° only. Tests with artificial movement patterns strongly suggest that this phase sensitivity is not a matter of the frequency composition of the natural movement pattern. Based on our modeling results, we propose that a constant phase difference is coded into the CPG of the antennal motor system and that proprioceptors are acting locally to regulate the joint movement amplitude.
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Affiliation(s)
- Nalin Harischandra
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University Bielefeld, Germany ; Cognitive Interaction Technology Center of Excellence (CITEC), Bielefeld University Bielefeld, Germany
| | - André F Krause
- Cognitive Interaction Technology Center of Excellence (CITEC), Bielefeld University Bielefeld, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University Bielefeld, Germany ; Cognitive Interaction Technology Center of Excellence (CITEC), Bielefeld University Bielefeld, Germany
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Ache JM, Dürr V. A Computational Model of a Descending Mechanosensory Pathway Involved in Active Tactile Sensing. PLoS Comput Biol 2015; 11:e1004263. [PMID: 26158851 PMCID: PMC4497639 DOI: 10.1371/journal.pcbi.1004263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 04/02/2015] [Indexed: 12/04/2022] Open
Abstract
Many animals, including humans, rely on active tactile sensing to explore the environment and negotiate obstacles, especially in the dark. Here, we model a descending neural pathway that mediates short-latency proprioceptive information from a tactile sensor on the head to thoracic neural networks. We studied the nocturnal stick insect Carausius morosus, a model organism for the study of adaptive locomotion, including tactually mediated reaching movements. Like mammals, insects need to move their tactile sensors for probing the environment. Cues about sensor position and motion are therefore crucial for the spatial localization of tactile contacts and the coordination of fast, adaptive motor responses. Our model explains how proprioceptive information about motion and position of the antennae, the main tactile sensors in insects, can be encoded by a single type of mechanosensory afferents. Moreover, it explains how this information is integrated and mediated to thoracic neural networks by a diverse population of descending interneurons (DINs). First, we quantified responses of a DIN population to changes in antennal position, motion and direction of movement. Using principal component (PC) analysis, we find that only two PCs account for a large fraction of the variance in the DIN response properties. We call the two-dimensional space spanned by these PCs ‘coding-space’ because it captures essential features of the entire DIN population. Second, we model the mechanoreceptive input elements of this descending pathway, a population of proprioceptive mechanosensory hairs monitoring deflection of the antennal joints. Finally, we propose a computational framework that can model the response properties of all important DIN types, using the hair field model as its only input. This DIN model is validated by comparison of tuning characteristics, and by mapping the modelled neurons into the two-dimensional coding-space of the real DIN population. This reveals the versatility of the framework for modelling a complete descending neural pathway. Many nocturnal and burrowing animals rely on their tactile sense to explore the surrounding space, and tactile cues are often used to adapt locomotion to a structurally complex environment. Most mammals use facial whiskers for active tactile exploration, while most insects use their antennae. Since whiskers and antennae are long, thin, cylindrical structures, they must be moved to probe the surrounding space. The nervous system therefore has to keep track of tactile sensor movement by encoding sensor position and motion in order to locate tactile contacts. Here, we model a descending neural pathway of the stick insect, which transfers information about tactile sensor movement to thoracic neural networks with short latency. We show that information about sensor position and motion can be derived from a single class of proprioceptors at the antennal joints, and present a computational model that explains the activity of four previously described groups of descending interneurons during antennal stimulation. Our model is validated against electrophysiological data on antennal mechanoreceptors and descending interneurons.
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Affiliation(s)
- Jan M. Ache
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology–Center of Excellence, Bielefeld University, Bielefeld, Germany
- * E-mail: (JMA); (VD)
| | - Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology–Center of Excellence, Bielefeld University, Bielefeld, Germany
- * E-mail: (JMA); (VD)
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Abstract
Much like visually impaired humans use a white-cane, nocturnal insects and mammals use antennae or whiskers for near-range orientation. Stick insects, for example, rely heavily on antennal tactile cues to find footholds and detect obstacles. Antennal contacts can even induce aimed reaching movements. Because tactile sensors are essentially one-dimensional, they must be moved to probe the surrounding space. Sensor movement is thus an essential cue for tactile sensing, which needs to be integrated by thoracic networks for generating appropriate adaptive leg movements. Based on single and double recordings, we describe a descending neural pathway comprising three identified ON- and OFF-type neurons that convey complementary, unambiguous, and short-latency information about antennal movement to thoracic networks in the stick insect. The neurons are sensitive to the velocity of antennal movements across the entire range covered by natural movements, regardless of movement direction and joint angle. Intriguingly, none of them originates from the brain. Instead, they descend from the gnathal ganglion and receive input from antennal mechanoreceptors in this lower region of the CNS. From there, they convey information about antennal movement to the thorax. One of the descending neurons, which is additionally sensitive to substrate vibration, feeds this information back to the brain via an ascending branch. We conclude that descending interneurons with complementary tuning characteristics, gains, input and output regions convey detailed information about antennal movement to thoracic networks. This pathway bypasses higher processing centers in the brain and thus constitutes a shortcut between tactile sensors on the head and the thorax.
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Theunissen LM, Bekemeier HH, Dürr V. Comparative whole-body kinematics of closely related insect species with different body morphology. ACTA ACUST UNITED AC 2014; 218:340-52. [PMID: 25524984 DOI: 10.1242/jeb.114173] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Legged locomotion through natural environments is very complex and variable. For example, leg kinematics may differ strongly between species, but even within the same species it is adaptive and context-dependent. Inter-species differences in locomotion are often difficult to interpret, because both morphological and ecological differences among species may be strong and, as a consequence, confound each other's effects. In order to understand better how body morphology affects legged locomotion, we compare unrestrained whole-body kinematics of three stick insect species with different body proportions, but similar feeding ecology: Carausius morosus, Aretaon asperrimus and Medauroidea extradentata (=Cuniculina impigra). In order to co-vary locomotory context, we introduced a gradually increasing demand for climbing by varying the height of stairs in the setup. The species were similar in many aspects, for example in using distinct classes of steps, with minor differences concerning the spread of corrective short steps. Major differences were related to antenna length, segment lengths of thorax and head, and the ratio of leg length to body length. Whereas all species continuously moved their antennae, only Medauroidea executed high swing movements with its front legs to search for obstacles in the near-range environment. Although all species adjusted their body inclination, the range in which body segments moved differed considerably, with longer thorax segments tending to be moved more. Finally, leg posture, time courses of leg joint angles and intra-leg coordination differed most strongly in long-legged Medauroidea.
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Affiliation(s)
- Leslie M Theunissen
- Biological Cybernetics, Faculty of Biology, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany Cognitive Interaction Technology - Center of Excellence, Bielefeld University, Inspiration 1, 33615 Bielefeld, Germany
| | - Holger H Bekemeier
- Biological Cybernetics, Faculty of Biology, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany Cognitive Interaction Technology - Center of Excellence, Bielefeld University, Inspiration 1, 33615 Bielefeld, Germany
| | - Volker Dürr
- Biological Cybernetics, Faculty of Biology, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany Cognitive Interaction Technology - Center of Excellence, Bielefeld University, Inspiration 1, 33615 Bielefeld, Germany
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Goldschmidt D, Wörgötter F, Manoonpong P. Biologically-inspired adaptive obstacle negotiation behavior of hexapod robots. Front Neurorobot 2014; 8:3. [PMID: 24523694 PMCID: PMC3905219 DOI: 10.3389/fnbot.2014.00003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/10/2014] [Indexed: 11/13/2022] Open
Abstract
Neurobiological studies have shown that insects are able to adapt leg movements and posture for obstacle negotiation in changing environments. Moreover, the distance to an obstacle where an insect begins to climb is found to be a major parameter for successful obstacle negotiation. Inspired by these findings, we present an adaptive neural control mechanism for obstacle negotiation behavior in hexapod robots. It combines locomotion control, backbone joint control, local leg reflexes, and neural learning. While the first three components generate locomotion including walking and climbing, the neural learning mechanism allows the robot to adapt its behavior for obstacle negotiation with respect to changing conditions, e.g., variable obstacle heights and different walking gaits. By successfully learning the association of an early, predictive signal (conditioned stimulus, CS) and a late, reflex signal (unconditioned stimulus, UCS), both provided by ultrasonic sensors at the front of the robot, the robot can autonomously find an appropriate distance from an obstacle to initiate climbing. The adaptive neural control was developed and tested first on a physical robot simulation, and was then successfully transferred to a real hexapod robot, called AMOS II. The results show that the robot can efficiently negotiate obstacles with a height up to 85% of the robot's leg length in simulation and 75% in a real environment.
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Affiliation(s)
- Dennis Goldschmidt
- Bernstein Center for Computational Neuroscience, Third Institute of Physics, Georg-August-Universität GöttingenGöttingen, Germany
- Institute of Neuroinformatics, University of Zurich and ETH ZurichZurich, Switzerland
| | - Florentin Wörgötter
- Bernstein Center for Computational Neuroscience, Third Institute of Physics, Georg-August-Universität GöttingenGöttingen, Germany
| | - Poramate Manoonpong
- Bernstein Center for Computational Neuroscience, Third Institute of Physics, Georg-August-Universität GöttingenGöttingen, Germany
- Mærsk Mc-Kinney Møller Institute, University of Southern DenmarkOdense, Denmark
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Theunissen LM, Vikram S, Dürr V. Spatial coordination of foot contacts in unrestrained climbing insects. J Exp Biol 2014; 217:3242-53. [DOI: 10.1242/jeb.108167] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Animals that live in a spatially complex environment such as the canopy of a tree, constantly need to find reliable foothold in three-dimensional (3D) space. In multi-legged animals, spatial coordination among legs is thought to improve efficiency of finding foothold by avoiding searching-movements in trailing legs. In stick insects, a "targeting mechanism" has been described that guides foot-placement of hind and middle legs according to the position of their leading ipsilateral leg. So far, this mechanism was shown for standing and tethered walking animals on horizontal surfaces. Here, we investigate the efficiency of this mechanism in spatial limb coordination of unrestrained climbing animals. For this, we recorded whole-body kinematics of freely climbing stick insects and analyzed foot placement in 3D space. We found that touch-down positions of adjacent legs were highly correlated in all three spatial dimensions, revealing 3D coordinate transfer among legs. Furthermore, targeting precision depended on the position of the leading leg. A second objective was to test the importance of sensory information transfer between legs. For this, we ablated a proprioceptive hair field signaling the levation of the leg. After ablation, the operated leg swung higher and performed unexpected searching-movements. Furthermore, targeting of the ipsilateral trailing leg was less precise in antero-posterior and in dorso-ventral directions. Our results reveal that the targeting mechanism is used by unrestrained climbing stick insects in 3D space and that information from the trochanteral hair field is used in ipsilateral spatial coordination among legs.
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Theunissen LM, Dürr V. Insects use two distinct classes of steps during unrestrained locomotion. PLoS One 2013; 8:e85321. [PMID: 24376877 PMCID: PMC3871641 DOI: 10.1371/journal.pone.0085321] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/25/2013] [Indexed: 12/03/2022] Open
Abstract
Background Adaptive, context-dependent control of locomotion requires modulation of centrally generated rhythmic motor patterns through peripheral control loops and postural reflexes. Thus assuming that the modulation of rhythmic motor patterns accounts for much of the behavioural variability observed in legged locomotion, investigating behavioural variability is a key to the understanding of context-dependent control mechanisms in locomotion. To date, the variability of unrestrained locomotion is poorly understood, and virtually nothing is known about the features that characterise the natural statistics of legged locomotion. In this study, we quantify the natural variability of hexapedal walking and climbing in insects, drawing from a database of several thousand steps recorded over two hours of walking time. Results We show that the range of step length used by unrestrained climbing stick insects is large, showing that step length can be changed substantially for adaptive locomotion. Step length distributions were always bimodal, irrespective of leg type and walking condition, suggesting the presence of two distinct classes of steps: short and long steps. Probability density of step length was well-described by a gamma distribution for short steps, and a logistic distribution for long steps. Major coefficients of these distributions remained largely unaffected by walking conditions. Short and long steps differed concerning their spatial occurrence on the walking substrate, their timing within the step sequence, and their prevalent swing direction. Finally, ablation of structures that serve to improve foothold increased the ratio of short to long steps, indicating a corrective function of short steps. Conclusions Statistical and functional differences suggest that short and long steps are physiologically distinct classes of leg movements that likely reflect distinct control mechanisms at work.
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Affiliation(s)
- Leslie M. Theunissen
- Department of Biological Cybernetics, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology - Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Bielefeld University, Bielefeld, Germany
- Cognitive Interaction Technology - Center of Excellence, Bielefeld University, Bielefeld, Germany
- * E-mail:
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Ache JM, Dürr V. Encoding of near-range spatial information by descending interneurons in the stick insect antennal mechanosensory pathway. J Neurophysiol 2013; 110:2099-112. [DOI: 10.1152/jn.00281.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Much like mammals use their whiskers, insects use their antennae for tactile near-range orientation during locomotion. Stick insects rapidly transfer spatial information about antennal touch location to the front legs, allowing for aimed reach-to-grasp movements. This adaptive behavior requires a spatial coordinate transformation from “antennal contact space” to “leg posture space.” Therefore, a neural pathway must convey proprioceptive and tactile information about antennal posture and contact site to thoracic motor networks. Here we analyze proprioceptive encoding properties of descending interneurons (DINs) that convey information about antennal posture and movement to the thoracic ganglia. On the basis of response properties of 110 DINs to imposed movement of the distal antennal joint, we distinguish five functional DIN groups according to their sensitivity to three parameters: movement direction, movement velocity, and antennal joint angle. These groups are simple position-sensitive DINs, which signal the antennal joint angle; dynamic position-sensitive DINs, which signal the joint angle with strong dependence on movement; unspecific movement-sensitive DINs, which signal movement but not the velocity, position, or direction of movement; and ON- and OFF-type velocity-sensitive DINs. The activity of the latter two groups is increased/attenuated during antennal movement, with the spike rate increasing/decreasing linearly with antennal joint angle velocity. Some movement-sensitive DINs convey spikes to the thorax within 11 ms, suggesting a rapid, direct pathway from antennal mechanosensory to thoracic motor networks. We discuss how the population of DINs could provide the neural basis for the intersegmental spatial coordinate transfer between a touch sensor of the head and thoracic motor networks.
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Affiliation(s)
- Jan M. Ache
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany; and
- Cognitive Interaction Technology—Center of Excellence, Bielefeld University, Bielefeld, Germany
| | - Volker Dürr
- Department of Biological Cybernetics, Faculty of Biology, Bielefeld University, Bielefeld, Germany; and
- Cognitive Interaction Technology—Center of Excellence, Bielefeld University, Bielefeld, Germany
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Schilling M, Paskarbeit J, Hoinville T, Hüffmeier A, Schneider A, Schmitz J, Cruse H. A hexapod walker using a heterarchical architecture for action selection. Front Comput Neurosci 2013; 7:126. [PMID: 24062682 PMCID: PMC3774992 DOI: 10.3389/fncom.2013.00126] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 08/24/2013] [Indexed: 11/30/2022] Open
Abstract
Moving in a cluttered environment with a six-legged walking machine that has additional body actuators, therefore controlling 22 DoFs, is not a trivial task. Already simple forward walking on a flat plane requires the system to select between different internal states. The orchestration of these states depends on walking velocity and on external disturbances. Such disturbances occur continuously, for example due to irregular up-and-down movements of the body or slipping of the legs, even on flat surfaces, in particular when negotiating tight curves. The number of possible states is further increased when the system is allowed to walk backward or when front legs are used as grippers and cannot contribute to walking. Further states are necessary for expansion that allow for navigation. Here we demonstrate a solution for the selection and sequencing of different (attractor) states required to control different behaviors as are forward walking at different speeds, backward walking, as well as negotiation of tight curves. This selection is made by a recurrent neural network (RNN) of motivation units, controlling a bank of decentralized memory elements in combination with the feedback through the environment. The underlying heterarchical architecture of the network allows to select various combinations of these elements. This modular approach representing an example of neural reuse of a limited number of procedures allows for adaptation to different internal and external conditions. A way is sketched as to how this approach may be expanded to form a cognitive system being able to plan ahead. This architecture is characterized by different types of modules being arranged in layers and columns, but the complete network can also be considered as a holistic system showing emergent properties which cannot be attributed to a specific module.
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Affiliation(s)
- Malte Schilling
- Center of Excellence 'Cognitive Interaction Technology,' Bielefeld University Germany
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Niven J. Invertebrate Neurobiology: Short-Term Memories for Limb Targeting. Curr Biol 2013; 23:R324-6. [DOI: 10.1016/j.cub.2013.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wosnitza A, Engelen J, Gruhn M. Segment-specific and state-dependent targeting accuracy of the stick insect. J Exp Biol 2013; 216:4172-83. [DOI: 10.1242/jeb.092106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
In its natural habitat, Carausius morosus climbs on the branches of bushes and trees. Previous work suggested that stick insects perform targeting movements with their hind legs to find support more easily. It has been assumed that the animals use position information from the anterior legs to control the touchdown position of the ipsilateral posterior legs. Here we address the questions if not only the hind but also the middle leg performs targeting, and if targeting is still present in a walking animal when influences of mechanical coupling through the ground are removed. If this were the case, it would emphasize the role of underlying neuronal mechanisms. We studied whether targeting occurred in both legs, when the rostral neighboring leg, i.e. either middle- or front leg, was placed at defined positions relative to the body, and analyzed targeting precision for dependency on the targeted position. Under these conditions, the touchdown positions of the hind legs show correlation to the position of the middle leg parallel and perpendicular to the body axis while only weak correlation exists between the middle and front legs, and only in parallel to the body axis. In continuously walking tethered animals targeting accuracy of hind and middle legs parallel to the body axis was barely different. However, targeting became significantly more accurate perpendicular to the body axis. Our results suggest that a neural mechanism exists for controlling the touchdown position of the posterior leg but that the strength of this mechanism is segment-specific and dependent on the behavioral context in which it is used.
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39
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Guo P, Ritzmann RE. Neural activity in the central complex of the cockroach brain is linked to turning behaviors. ACTA ACUST UNITED AC 2012. [PMID: 23197098 DOI: 10.1242/jeb.080473] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
An animal moving through complex terrain must consider sensory cues around it and alter its movements accordingly. In the arthropod brain, the central complex (CC) receives highly preprocessed sensory information and sends outputs to premotor regions, suggesting that it may play a role in the central control of oriented locomotion. We performed tetrode recordings within the CC in cockroaches walking on an air-suspended ball to examine the role of the CC in turning behaviors. When a rod was placed near the cockroach's head, the cockroach touched the rod repeatedly with one or both antennae before locomotion was initiated. Some CC units responded to self-generated antennal contact with the object, but at lower levels compared with externally imposed antennal stimulation. The neural activity of other CC units responded to locomotion. We found that some CC units showed discrete firing fields corresponding to specific locomotion states. We also found that changes in firing rate of some CC units preceded changes in turning speed in one direction but not the other. Furthermore, such biased units were located in the side of the brain ipsilateral to the direction of the turning speed they could predict. Moreover, electrical stimulation of the CC elicited or modified locomotion, and the direction of some evoked locomotion could be predicted by the response property of locomotion-predictive units near the stimulation site. Therefore, our results suggest that, at the population level, asymmetrical activity in the CC precedes and influences turning behavior.
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Affiliation(s)
- Peiyuan Guo
- Case Western Reserve University, 2080 Adelbert Road, DeGrace 214, Cleveland, OH 44106, USA.
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Berg E, Büschges A, Schmidt J. Single perturbations cause sustained changes in searching behavior in stick insects. ACTA ACUST UNITED AC 2012. [PMID: 23197090 DOI: 10.1242/jeb.076406] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Stick insects (Cuniculina impigra) possessing only a single front leg perform untargeted stereotypical cyclic searching movements with that leg when it loses contact with the ground. When encountering an object, the animals grasp it. We hypothesized that removal of the object immediately after contact with the leg's tibia would result in a change in searching strategy, i.e. searching movements confined to the former location of the object to regain contact. In our experimental setup, searching movements were restricted to upward and downward movements. After removal of the object, searching movements were continued. However, in post-contact searching, two movement parameters were usually changed: (1) average positions of searching movements were shifted towards the former position of the object; and (2) movement amplitudes were considerably smaller and accompanied by a decrease in cycle period. This confinement of searching movements to the location of contact was interpreted as targeting behavior. All parameters regained initial values after approximately 6 s. Changes in position and amplitudes were independently controlled. Neither of the changes was under visual control, but rather depended on the presence of the trochanteral hairplate, a sensory organ that measures the coxa-trochanter joint position. Changes in average leg position were linked to changes in the ratio of electrical activity in the levator and depressor trochanteris muscles, which were based on altered activity in both or either one of the muscles. Our data demonstrate a switch in a simple behavior that is under local sensory control and may utilize a form of short-term memory.
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Affiliation(s)
- Eva Berg
- Department of Animal Physiology, Zoological Institute, Biocenter Cologne, University of Cologne, 50674 Cologne, Germany
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41
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Schilling M, Cruse H. What's Next: Recruitment of a Grounded Predictive Body Model for Planning a Robot's Actions. Front Psychol 2012; 3:383. [PMID: 23060845 PMCID: PMC3466120 DOI: 10.3389/fpsyg.2012.00383] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 09/14/2012] [Indexed: 11/13/2022] Open
Abstract
Even comparatively simple, reactive systems are able to control complex motor tasks, such as hexapod walking on unpredictable substrate. The capability of such a controller can be improved by introducing internal models of the body and of parts of the environment. Such internal models can be applied as inverse models, as forward models or to solve the problem of sensor fusion. Usually, separate models are used for these functions. Furthermore, separate models are used to solve different tasks. Here we concentrate on internal models of the body as the brain considers its own body the most important part of the world. The model proposed is formed by a recurrent neural network with the property of pattern completion. The model shows a hierarchical structure but nonetheless comprises a holistic system. One and the same model can be used as a forward model, as an inverse model, for sensor fusion, and, with a simple expansion, as a model to internally simulate (new) behaviors to be used for prediction. The model embraces the geometrical constraints of a complex body with many redundant degrees of freedom, and allows finding geometrically possible solutions. To control behavior such as walking, climbing, or reaching, this body model is complemented by a number of simple reactive procedures together forming a procedural memory. In this article, we illustrate the functioning of this network. To this end we present examples for solutions of the forward function and the inverse function, and explain how the complete network might be used for predictive purposes. The model is assumed to be “innate,” so learning the parameters of the model is not (yet) considered.
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Affiliation(s)
- Malte Schilling
- International Computer Science Institute Berkeley, CA, USA ; Center of Excellence 'Cognitive Interaction Technology', University of Bielefeld Bielefeld, Germany
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42
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Patanè L, Hellbach S, Krause AF, Arena P, Dürr V. An insect-inspired bionic sensor for tactile localization and material classification with state-dependent modulation. Front Neurorobot 2012; 6:8. [PMID: 23055967 PMCID: PMC3458430 DOI: 10.3389/fnbot.2012.00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/18/2012] [Indexed: 12/05/2022] Open
Abstract
Insects carry a pair of antennae on their head: multimodal sensory organs that serve a wide range of sensory-guided behaviors. During locomotion, antennae are involved in near-range orientation, for example in detecting, localizing, probing, and negotiating obstacles. Here we present a bionic, active tactile sensing system inspired by insect antennae. It comprises an actuated elastic rod equipped with a terminal acceleration sensor. The measurement principle is based on the analysis of damped harmonic oscillations registered upon contact with an object. The dominant frequency of the oscillation is extracted to determine the distance of the contact point along the probe and basal angular encoders allow tactile localization in a polar coordinate system. Finally, the damping behavior of the registered signal is exploited to determine the most likely material. The tactile sensor is tested in four approaches with increasing neural plausibility: first, we show that peak extraction from the Fourier spectrum is sufficient for tactile localization with position errors below 1%. Also, the damping property of the extracted frequency is used for material classification. Second, we show that the Fourier spectrum can be analysed by an Artificial Neural Network (ANN) which can be trained to decode contact distance and to classify contact materials. Thirdly, we show how efficiency can be improved by band-pass filtering the Fourier spectrum by application of non-negative matrix factorization. This reduces the input dimension by 95% while reducing classification performance by 8% only. Finally, we replace the FFT by an array of spiking neurons with gradually differing resonance properties, such that their spike rate is a function of the input frequency. We show that this network can be applied to detect tactile contact events of a wheeled robot, and how detrimental effects of robot velocity on antennal dynamics can be suppressed by state-dependent modulation of the input signals.
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Affiliation(s)
- Luca Patanè
- Dipartimento di Ingegneria Elettrica Elettronica e Informatica, University of Catania Catania, Italy
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Ritzmann RE, Harley CM, Daltorio KA, Tietz BR, Pollack AJ, Bender JA, Guo P, Horomanski AL, Kathman ND, Nieuwoudt C, Brown AE, Quinn RD. Deciding which way to go: how do insects alter movements to negotiate barriers? Front Neurosci 2012; 6:97. [PMID: 22783160 PMCID: PMC3390555 DOI: 10.3389/fnins.2012.00097] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 06/13/2012] [Indexed: 11/13/2022] Open
Abstract
Animals must routinely deal with barriers as they move through their natural environment. These challenges require directed changes in leg movements and posture performed in the context of ever changing internal and external conditions. In particular, cockroaches use a combination of tactile and visual information to evaluate objects in their path in order to effectively guide their movements in complex terrain. When encountering a large block, the insect uses its antennae to evaluate the object’s height then rears upward accordingly before climbing. A shelf presents a choice between climbing and tunneling that depends on how the antennae strike the shelf; tapping from above yields climbing, while tapping from below causes tunneling. However, ambient light conditions detected by the ocelli can bias that decision. Similarly, in a T-maze turning is determined by antennal contact but influenced by visual cues. These multi-sensory behaviors led us to look at the central complex as a center for sensori-motor integration within the insect brain. Visual and antennal tactile cues are processed within the central complex and, in tethered preparations, several central complex units changed firing rates in tandem with or prior to altered step frequency or turning, while stimulation through the implanted electrodes evoked these same behavioral changes. To further test for a central complex role in these decisions, we examined behavioral effects of brain lesions. Electrolytic lesions in restricted regions of the central complex generated site specific behavioral deficits. Similar changes were also found in reversible effects of procaine injections in the brain. Finally, we are examining these kinds of decisions made in a large arena that more closely matches the conditions under which cockroaches forage. Overall, our studies suggest that CC circuits may indeed influence the descending commands associated with navigational decisions, thereby making them more context dependent.
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Affiliation(s)
- Roy E Ritzmann
- Department of Biology, Case Western Reserve University Cleveland, OH, USA
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Krause AF, Dürr V. Active tactile sampling by an insect in a step-climbing paradigm. Front Behav Neurosci 2012; 6:30. [PMID: 22754513 PMCID: PMC3384986 DOI: 10.3389/fnbeh.2012.00030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 06/01/2012] [Indexed: 11/21/2022] Open
Abstract
Many insects actively explore their near-range environment with their antennae. Stick insects (Carausius morosus) rhythmically move their antennae during walking and respond to antennal touch by repetitive tactile sampling of the object. Despite its relevance for spatial orientation, neither the spatial sampling patterns nor the kinematics of antennation behavior in insects are understood. Here we investigate unrestrained bilateral sampling movements during climbing of steps. The main objectives are: (1) How does the antennal contact pattern relate to particular object features? (2) How are the antennal joints coordinated during bilateral tactile sampling? We conducted motion capture experiments on freely climbing insects, using steps of different height. Tactile sampling was analyzed at the level of antennal joint angles. Moreover, we analyzed contact patterns on the surfaces of both the obstacle and the antenna itself. Before the first contact, both antennae move in a broad, mostly elliptical exploratory pattern. After touching the obstacle, the pattern switches to a narrower and faster movement, caused by higher cycle frequencies and lower cycle amplitudes in all joints. Contact events were divided into wall- and edge-contacts. Wall contacts occurred mostly with the distal third of the flagellum, which is flexible, whereas edge contacts often occurred proximally, where the flagellum is stiff. The movement of both antennae was found to be coordinated, exhibiting bilateral coupling of functionally analogous joints [e.g., left head-scape (HS) joint with right scape-pedicel (SP) joint] throughout tactile sampling. In comparison, bilateral coupling between homologous joints (e.g., both HS joints) was significantly weaker. Moreover, inter-joint coupling was significantly weaker during the contact episode than before. In summary, stick insects show contact-induced changes in frequency, amplitude and inter-joint coordination during tactile sampling of climbed obstacles.
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Affiliation(s)
- André F. Krause
- Cognitive Interaction Technology – Centre of Excellence, Universität BielefeldBielefeld, Germany
| | - Volker Dürr
- Cognitive Interaction Technology – Centre of Excellence, Universität BielefeldBielefeld, Germany
- Fakultät für Biologie, Lehrstuhl für Biologische Kybernetik, Universität BielefeldBielefeld, Germany
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Krause AF, Winkler A, Dürr V. Central drive and proprioceptive control of antennal movements in the walking stick insect. ACTA ACUST UNITED AC 2012; 107:116-29. [PMID: 22728470 DOI: 10.1016/j.jphysparis.2012.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 06/11/2012] [Accepted: 06/11/2012] [Indexed: 11/19/2022]
Abstract
In terrestrial locomotion, active touch sensing is an important source of near-range information. Walking stick insects show active tactile exploration behaviour by continuously sampling the ambient space with their antennae. Here, we identify central and proprioceptive contributions to the control of this behaviour. First, we investigate the potential role of synaptic drive to central neural networks using pilocarpine, an agonist of muscarinic acetylcholine receptors. In an in situ preparation, pilocarpine induced rhythmic antennal movements with a persisting pattern of inter-joint coordination, matching that seen in intact walking animals, albeit with lower cycle frequency. After de-cerebration, stick insects were still able to walk but no longer moved their antennae during walking. Here, pilocarpine still induced antennal movement, suggesting that synaptic drive to central neural networks involved in antennal movement generation occurred in the brain and not in the suboesophageal ganglion. During intact walking, these networks are likely to receive activation by ascending input. Second, we show persistent coupling of both antennal joints during intact walking, with the distal scape-pedicel joint (SP) always leading the proximal head-scape joint (HS). Ablation of joint proprioceptors had no effect on this overall pattern of inter-joint coordination but could affect the magnitude of the phase-lag. Third, we revise the description of antennal hair fields and show that complete ablation of all seven hair fields strongly affects antennal movements. Ablating dorsal hair fields mainly affected the working-ranges of antennal joints: Ablation of the dorso-medial pedicellar hair plate caused a ventral shift of the SP working-range. Ablation of the dorsal scapal hair plate considerably expanded the dorsal HS working-range, and, in combination with ablation of pedicellar hair fields, increased the SP working-range, too. We conclude that the working-ranges of both joints are under proprioceptive control of dorsal antennal hair fields. Thus, both synaptic drive to central neural networks and proprioceptive feedback are involved in the control of active tactile exploration behaviour in stick insects.
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Affiliation(s)
- André F Krause
- Lehrstuhl für Biologische Kybernetik, Fakultät für Biologie, Universität Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany; Cognitive Interaction Technology, Center of Excellence, Universität Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany
| | - Andrea Winkler
- Lehrstuhl für Biologische Kybernetik, Fakultät für Biologie, Universität Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany
| | - Volker Dürr
- Lehrstuhl für Biologische Kybernetik, Fakultät für Biologie, Universität Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany; Cognitive Interaction Technology, Center of Excellence, Universität Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany.
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Comer C, Baba Y. Active touch in orthopteroid insects: behaviours, multisensory substrates and evolution. Philos Trans R Soc Lond B Biol Sci 2012; 366:3006-15. [PMID: 21969682 DOI: 10.1098/rstb.2011.0149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Orthopteroid insects (cockroaches, crickets, locusts and related species) allow examination of active sensory processing in a comparative framework. Some orthopteroids possess long, mobile antennae endowed with many chemo- and mechanoreceptors. When the antennae are touched, an animal's response depends upon the identity of the stimulus. For example, contact with a predator may lead to escape, but contact with a conspecific may usually not. Active touch of an approaching object influences the likelihood that a discrimination of identity will be made. Using cockroaches, we have identified specific descending mechanosensory interneurons that trigger antennal-mediated escape. Crucial sensory input to these cells comes from chordotonal organs within the antennal base. However, information from other receptors on the base or the long antennal flagellum allows active touch to modulate escape probability based on stimulus identity. This is conveyed, at least to some extent, by textural information. Guidance of the antennae in active exploration depends on visual information. Some of the visual interneurons and the motor neurons necessary for visuomotor control have been identified. Comparisons across Orthoptera suggest an evolutionary model where subtle changes in the architecture of interneurons, and of sensorimotor control loops, may explain differing levels of vision-touch interaction in the active guidance of behaviour.
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Affiliation(s)
- Christopher Comer
- Division of Biological Sciences, 136 Liberal Arts Bldg, The University of Montana, Missoula, MT 59812, USA.
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Abstract
Active sensing systems are purposive and information-seeking sensory systems. Active sensing usually entails sensor movement, but more fundamentally, it involves control of the sensor apparatus, in whatever manner best suits the task, so as to maximize information gain. In animals, active sensing is perhaps most evident in the modality of touch. In this theme issue, we look at active touch across a broad range of species from insects, terrestrial and marine mammals, through to humans. In addition to analysing natural touch, we also consider how engineering is beginning to exploit physical analogues of these biological systems so as to endow robots with rich tactile sensing capabilities. The different contributions show not only the varieties of active touch--antennae, whiskers and fingertips--but also their commonalities. They explore how active touch sensing has evolved in different animal lineages, how it serves to provide rapid and reliable cues for controlling ongoing behaviour, and even how it can disintegrate when our brains begin to fail. They demonstrate that research on active touch offers a means both to understand this essential and primary sensory modality, and to investigate how animals, including man, combine movement with sensing so as to make sense of, and act effectively in, the world.
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Affiliation(s)
- Tony J Prescott
- University of Sheffield-Psychology, Western Bank, Sheffield S10 2TN, UK.
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Behavioral response to antennal tactile stimulation in the field cricket Gryllus bimaculatus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 198:557-65. [PMID: 22534774 DOI: 10.1007/s00359-012-0729-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 04/12/2012] [Accepted: 04/13/2012] [Indexed: 10/28/2022]
Abstract
We examined behavioral responses of the field cricket Gryllus bimaculatus to tactile stimuli to the antennae. Three stimulants of similar shape and size but different textures were used: a tibia from the hunting spider Heteropoda venatoria (potential predator), a tibia from the orb-web spider Argiope bruennichi (less likely predator), and a glass rod. Each stimulus session comprised a first gentle contact and a second strong contact. The evoked behavioral responses were classified into four categories: aversion, aggression, antennal search, and no response. Regardless of the stimulants, the crickets exhibited antennal search and aversion most frequently in response to the first and second stimuli, respectively. The frequency of aversion was significantly higher to the tibia of H. venatoria than to other stimulants. The most striking observation was that aggressive responses were exclusive to the H. venatoria tibia. To specify the hair type that induced aggression, we manipulated two types of common hairs (bristle and fine) on the tibia of the predatory spider. When bristle hairs were removed from the H. venatoria tibia, aggression was significantly reduced. These results suggest that antennae can discriminate the tactile texture of external objects and elicit adaptive behavioral responses.
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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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Dirks JH, Dürr V. Biomechanics of the stick insect antenna: damping properties and structural correlates of the cuticle. J Mech Behav Biomed Mater 2011; 4:2031-42. [PMID: 22098903 DOI: 10.1016/j.jmbbm.2011.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 06/28/2011] [Accepted: 07/01/2011] [Indexed: 11/17/2022]
Abstract
The antenna of the Indian stick insect Carausius morosus is a highly specialized near-range sensory probe used to actively sample tactile cues about location, distance or shape of external objects in real time. The length of the antenna's flagellum is 100 times the diameter at the base, making it a very delicate and slender structure. Like the rest of the insect body, it is covered by a protective exoskeletal cuticle, making it stiff enough to allow controlled, active, exploratory movements and hard enough to resist damage and wear. At the same time, it is highly flexible in response to contact forces, and returns rapidly to its straight posture without oscillations upon release of contact force. Which mechanical adaptations allow stick insects to unfold the remarkable combination of maintaining a sufficiently invariant shape between contacts and being sufficiently compliant during contact? What role does the cuticle play? Our results show that, based on morphological differences, the flagellum can be divided into three zones, consisting of a tapered cone of stiff exocuticle lined by an inner wedge of compliant endocuticle. This inner wedge is thick at the antenna's base and thin at its distal half. The decay time constant after deflection, a measure that indicates strength of damping, is much longer at the base (τ>25 ms) than in the distal half (τ<18 ms) of the flagellum. Upon experimental desiccation, reducing mass and compliance of the endocuticle, the flagellum becomes under-damped. Analysing the frequency components indicates that the flagellum can be abstracted with the model of a double pendulum with springs and dampers in both joints. We conclude that in the stick-insect antenna the cuticle properties described are structural correlates of damping, allowing for a straight posture in the instant of a new contact event, combined with a maximum of flexibility.
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Affiliation(s)
- Jan-Henning Dirks
- Department of Mechanical and Manufacturing Engineering, Trinity College Dublin, 2 Dublin, Ireland.
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