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Campaniform sensilla

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Sasha N Zill – 1st expert on this subject based on the ideXlab platform

  • Force dynamics and synergist muscle activation in stick insects: the effects of using joint torques as mechanical stimuli
    Journal of Neurophysiology, 2018
    Co-Authors: Sasha N Zill, Ansgar Büschges, Sumaiya Chaudhry, Chris J. Dallmann, Josef Schmitz

    Abstract:

    The effects of force receptors (Campaniform sensilla) on leg muscles and synergies were characterized in stick insects using both ramp and hold functions and waveforms of joint torques calculated b…

  • Effects of force detecting sense organs on muscle synergies are correlated with their response properties.
    Arthropod Structure & Development, 2017
    Co-Authors: Sasha N Zill, Josef Schmitz, Sumaiya Chaudhry, David Neff, Annelie Exter, Ansgar Büschges

    Abstract:

    Sense organs that monitor forces in legs can contribute to activation of muscles as synergist groups. Previous studies in cockroaches and stick insects showed that Campaniform sensilla, receptors that encode forces via exoskeletal strains, enhance muscle synergies in substrate grip. However synergist activation was mediated by different groups of receptors in cockroaches (trochanteral sensilla) and stick insects (femoral sensilla). The factors underlying the differential effects are unclear as the responses of femoral Campaniform sensilla have not previously been characterized. The present study characterized the structure and response properties (via extracellular recording) of the femoral sensilla in both insects. The cockroach trochantero-femoral (TrF) joint is mobile and the joint membrane acts as an elastic antagonist to the reductor muscle. Cockroach femoral Campaniform sensilla show weak discharges to forces in the coxo-trochanteral (CTr) joint plane (in which forces are generated by coxal muscles) but instead encode forces directed posteriorly (TrF joint plane). In stick insects, the TrF joint is fused and femoral Campaniform sensilla discharge both to forces directed posteriorly and forces in the CTr joint plane. These findings support the idea that receptors that enhance synergies encode forces in the plane of action of leg muscles used in support and propulsion.

  • Force feedback reinforces muscle synergies in insect legs.
    Arthropod Structure & Development, 2015
    Co-Authors: Sasha N Zill, Ansgar Büschges, Sumaiya Chaudhry, Josef Schmitz

    Abstract:

    The nervous system solves complex biomechanical problems by activating muscles in modular, synergist groups. We have studied how force feedback in substrate grip is integrated with effects of sense organs that monitor support and propulsion in insects. Campaniform sensilla are mechanoreceptors that encode forces as cuticular strains. We tested the hypothesis that integration of force feedback from receptors of different leg segments during grip occurs through activation of specific muscle synergies. We characterized the effects of Campaniform sensilla of the feet (tarsi) and proximal segments (trochanter and femur) on activities of leg muscles in stick insects and cockroaches. In both species, mechanical stimulation of tarsal sensilla activated the leg muscle that generates substrate grip (retractor unguis), as well as proximal leg muscles that produce inward pull (tibial flexor) and support/propulsion (trochanteral depressor). Stimulation of Campaniform sensilla on proximal leg segments activated the same synergistic group of muscles. In stick insects, the effects of proximal receptors on distal leg muscles changed and were greatly enhanced when animals made active searching movements. In insects, the task-specific reinforcement of muscle synergies can ensure that substrate adhesion is rapidly established after substrate contact to provide a stable point for force generation.

Josef Schmitz – 2nd expert on this subject based on the ideXlab platform

  • Force dynamics and synergist muscle activation in stick insects: the effects of using joint torques as mechanical stimuli
    Journal of Neurophysiology, 2018
    Co-Authors: Sasha N Zill, Ansgar Büschges, Sumaiya Chaudhry, Chris J. Dallmann, Josef Schmitz

    Abstract:

    The effects of force receptors (Campaniform sensilla) on leg muscles and synergies were characterized in stick insects using both ramp and hold functions and waveforms of joint torques calculated b…

  • Effects of force detecting sense organs on muscle synergies are correlated with their response properties.
    Arthropod Structure & Development, 2017
    Co-Authors: Sasha N Zill, Josef Schmitz, Sumaiya Chaudhry, David Neff, Annelie Exter, Ansgar Büschges

    Abstract:

    Sense organs that monitor forces in legs can contribute to activation of muscles as synergist groups. Previous studies in cockroaches and stick insects showed that Campaniform sensilla, receptors that encode forces via exoskeletal strains, enhance muscle synergies in substrate grip. However synergist activation was mediated by different groups of receptors in cockroaches (trochanteral sensilla) and stick insects (femoral sensilla). The factors underlying the differential effects are unclear as the responses of femoral Campaniform sensilla have not previously been characterized. The present study characterized the structure and response properties (via extracellular recording) of the femoral sensilla in both insects. The cockroach trochantero-femoral (TrF) joint is mobile and the joint membrane acts as an elastic antagonist to the reductor muscle. Cockroach femoral Campaniform sensilla show weak discharges to forces in the coxo-trochanteral (CTr) joint plane (in which forces are generated by coxal muscles) but instead encode forces directed posteriorly (TrF joint plane). In stick insects, the TrF joint is fused and femoral Campaniform sensilla discharge both to forces directed posteriorly and forces in the CTr joint plane. These findings support the idea that receptors that enhance synergies encode forces in the plane of action of leg muscles used in support and propulsion.

  • Force feedback reinforces muscle synergies in insect legs.
    Arthropod Structure & Development, 2015
    Co-Authors: Sasha N Zill, Ansgar Büschges, Sumaiya Chaudhry, Josef Schmitz

    Abstract:

    The nervous system solves complex biomechanical problems by activating muscles in modular, synergist groups. We have studied how force feedback in substrate grip is integrated with effects of sense organs that monitor support and propulsion in insects. Campaniform sensilla are mechanoreceptors that encode forces as cuticular strains. We tested the hypothesis that integration of force feedback from receptors of different leg segments during grip occurs through activation of specific muscle synergies. We characterized the effects of Campaniform sensilla of the feet (tarsi) and proximal segments (trochanter and femur) on activities of leg muscles in stick insects and cockroaches. In both species, mechanical stimulation of tarsal sensilla activated the leg muscle that generates substrate grip (retractor unguis), as well as proximal leg muscles that produce inward pull (tibial flexor) and support/propulsion (trochanteral depressor). Stimulation of Campaniform sensilla on proximal leg segments activated the same synergistic group of muscles. In stick insects, the effects of proximal receptors on distal leg muscles changed and were greatly enhanced when animals made active searching movements. In insects, the task-specific reinforcement of muscle synergies can ensure that substrate adhesion is rapidly established after substrate contact to provide a stable point for force generation.

Faith S Frazier – 3rd expert on this subject based on the ideXlab platform

  • post embryonic development of cuticular caps of Campaniform sensilla of the cockroach leg potential implications in scaling force detection
    Arthropod Structure & Development, 2003
    Co-Authors: Angela L Ridgel, Faith S Frazier, Sasha N Zill

    Abstract:

    Abstract All animals generate progressively larger forces as they increase in size and mass. Their abilities to detect these forces must be similarly adjusted. In insects, Campaniform sensilla monitor strains in the exoskeleton and provide information about forces acting upon the legs. Each sensory neuron possesses a dendrite that inserts into a cuticular cap in the exoskeleton. The cap is the site of mechanotransduction. We measured the sizes and numbers of receptor caps on the cockroach hindleg at different developmental stages. Our goal was to identify morphological features that could be correlated with the range of forces that must be detected. As cockroaches increase in size through successive molts, the number of cuticular caps in each group increases. The tibial group, for example, has two sensilla in first instar animals and 10–12 in the adult. There is also an increase in the range of cap sizes within each group. Observations of animals and their molted exoskeletons suggest that this increase occurs as the caps of existing receptors increase in size and smaller ones are added with each molt. These changes may be important in increasing the range of forces the receptors can signal while retaining sensitivity to low levels of force.

  • force detection in cockroach walking reconsidered discharges of proximal tibial Campaniform sensilla when body load is altered
    Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2001
    Co-Authors: Adam J Noah, L. Quimby, Faith S Frazier, Sasha N Zill

    Abstract:

    We examined the mechanisms underlying force feedback in cockroach walking by recording sensory and motor activities in freely moving animals under varied load conditions. Tibial Campaniform sensilla monitor forces in the leg via strains in the exoskeleton. A subgroup (proximal receptors) discharge in the stance phase of walking. This activity has been thought to result from leg loading derived from body mass. We compared sensory activities when animals walked freely in an arena or on an oiled glass plate with their body weight supported. The plate was oriented either horizontally (70–75% of body weight supported) or vertically (with the gravitational vector parallel to the substrate). Proximal sensilla discharged following the onset of stance in all load conditions. In addition, activity was decreased in the middle third of the stance phase when the effect of body weight was reduced. Our results suggest that sensory discharges early in stance result from forces generated by contractions of muscles that press the leg as a lever against the substrate. These forces can unload legs already in stance and assure the smooth transition of support among the limbs. Force feedback later in stance may adjust motor output to changes in leg loading.

  • dynamic responses of tibial Campaniform sensilla studied by substrate displacement in freely moving cockroaches
    Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2001
    Co-Authors: Angela L Ridgel, Faith S Frazier, Sasha N Zill

    Abstract:

    Responses of the tibial Campaniform sensilla, receptors that encode strains in the exoskeleton, were characterized by recording sensory activities during perturbations in freely standing cockroaches. The substrate upon which the animal stood was displaced horizontally using ramp and hold stimuli at varied rates. The sensilla showed short latency responses that were initiated in the first 30 ms of platform movement. Responses of individual receptors depended upon the direction of displacement and the orientation of their cuticular cap. Proximal receptors, whose caps are perpendicular to the long axis of the tibia, responded to displacements directed from the contralateral side of the body and from the head toward the abdomen. The distal sensilla, oriented parallel to the tibia, discharged at longer latency to displacements in opposite directions. Plots of receptor activity versus displacement direction showed that proximal and distal sensilla are activated in non-overlapping ranges of movement direction. Afferent responses also increased as the platform was displaced more rapidly. These results are consistent with a model in which displacements produce forces that result in bending of the tibia. This information could be utilized to detect the direction and rate of forces that occur during leg slipping or in walking on unstable terrains.