scholarly journals The Subgenual Organ Complex in Stick Insects: Functional Morphology and Mechanical Coupling of a Complex Mechanosensory Organ

2021 ◽  
Vol 9 ◽  
Author(s):  
Johannes Strauß ◽  
Leif Moritz ◽  
Peter T. Rühr
Keyword(s):  
Anterior Part ◽  
Longitudinal Direction ◽  
Mechanical Coupling ◽  
Linear Set ◽  
Highly Sensitive ◽  
Stick Insects ◽  
Receptor Organ ◽  
Proprioceptive Function ◽  
Distal Direction ◽  
Subgenual Organ

Leg chordotonal organs in insects show different adaptations to detect body movements, substrate vibrations, or airborne sound. In the proximal tibia of stick insects occur two chordotonal organs: the subgenual organ, a highly sensitive vibration receptor organ, and the distal organ, of which the function is yet unknown. The distal organ consists of a linear set of scolopidial sensilla extending in the tibia in distal direction toward the tarsus. Similar organs occur in the elaborate hearing organs in crickets and bushcrickets, where the auditory sensilla are closely associated with thin tympanal membranes and auditory trachea in the leg. Here, we document the position and attachment points for the distal organ in three species of stick insects without auditory adaptations (Ramulus artemis, Sipyloidea sipylus, and Carausius morosus). The distal organ is located in the dorsal hemolymph channel and attaches at the proximal end to the dorsal and posterior leg cuticle by tissue strands. The central part of the distal organ is placed closer to the dorsal cuticle and is suspended by fine tissue strands. The anterior part is clearly separated from the tracheae, while the distal part of the organ is placed over the anterior trachea. The distal organ is not connected to a tendon or muscle, which would indicate a proprioceptive function. The sensilla in the distal organ have dendrites oriented in distal direction in the leg. This morphology does not reveal obvious auditory adaptations as in tympanal organs, while the position in the hemolymph channel and the direction of dendrites indicate responses to forces in longitudinal direction of the leg, likely vibrational stimuli transmitted in the leg’s hemolymph. The evolutionary convergence of complex chordotonal organs with linear sensilla sets between tympanal hearing organs and atympanate organs in stick insects is emphasized by the different functional morphologies and sensory specializations.

A new muscle receptor organ in the antenna of the rock lobster Palinurus vulgaris : mechanical, muscular and proprioceptive organization of the two proximal joints J0 and J1

1983 ◽  
Vol 218 (1210) ◽  
pp. 95-110 ◽  
Keyword(s):  
Anterior Part ◽  
Proximal Part ◽  
The Other ◽  
Chordotonal Organ ◽  
Excitatory Postsynaptic Potentials ◽  
Rock Lobster ◽  
Postsynaptic Potentials ◽  
Muscle Receptor ◽  
Physiological Properties ◽  
Receptor Organ

(i) Following previous work on the morphological and physiological properties of the two distal joints (J2, J3) of the atenna of the rock lobster Palinurus vulgaris , the mechanical, muscular and proprioceptive organization of the two proximal joints between the antennal segments S1 and S2 (J1) and between S1 and the cephalothorax (J0) have now been studied. (ii) Articulated by two classical condyles, J1 moves in a mediolateral plane. One external rotator muscle (ER) and three internal rotator muscles (IR1, IR2, IR3) subserve its movements. J0 is articulated by two different systems: a classical ventrolateral condyle and a complex sliding system constituted by special cuticular structures on the dorsomedial side of the S1 segment and on the rostrum between the two antennae. J0 moves in the dorsoventral plane by means of a levator muscle (Lm) and a depressor muscle (Dm). A third muscle, the lateral tractor muscle (LTm), associated with J0 and lying obliquely across S1, may modulate the level of friction between the S1 segment and the rostrum. (iii) Proprioception in J1 is achieved by a muscle receptor organ AMCO-J1 (antennal myochordotonal organ for the J1 joint) associating a small accessory muscle (S1.am) located in the proximal part of the S1 segment and a chordotonal organ inserted proximally on the S1.am muscle and distally on the S2 segment. J0 proprioception is ensured by a simple chordotonal organ (CO-J0) located in the anterior part of the cephalothorax. (iv) The S1.am muscle is innervated by three motoneurons characterized by their very small diameters and inducing respectively tonic excitatory postsynaptic potentials, phasic excitatory postsynaptic potentials and inhibitory postsynaptic potentials. Anatomical and physiological observations suggest functional correlation between S1.am and IR1 motor innervation. (v) Mechanical and muscular organization of J0 and J1 are compared with that of the other joints of the antenna. The properties of the AMCO-J1 proprioceptor are discussed in relation to the other muscle receptor organs described in crustaceans.

scholarly journals Non-Contact Damage Detection under Operational Conditions with Multipoint Laservibrometry

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 732 ◽  
Author(s):  
Xiaodong Cao ◽  
Christian Rembe
Keyword(s):  
Low Frequency ◽  
Operational Conditions ◽  
Mechanical Coupling ◽  
Vibration Behavior ◽  
Damage Indices ◽  
Highly Sensitive ◽  
Vibration Responses ◽  
Common Technique ◽  
Measurement Object ◽  
Response Vector

Scanning laser–Doppler vibrometry (SLDV) can localize and visualize damages in mechanical structures. In order to enable scanning, it is necessary to repeat the vibration. Therefore, this technique is not suited to detect emerging hazards in working machinery that change the vibration behavior. A common technique for such cases is monitoring the vibration excited by machine operation with accelerometers. This technique requires mechanical coupling between sensors and the measurement object, which influences the high-frequency vibration responses. However, in the low-frequency range, local damages do not shift resonances or distort operational deflection shapes (ODS) significantly. These alterations in the vibration behavior are tiny and hard to detect. This paper shows that multipoint laservibrometry (MPV) with laser excitation can measure these effects efficiently, and it further demonstrates that damages influence ODSs at frequencies above 20 kHz much stronger than at frequencies below 20 kHz. In addition, ODS-based damage indices are discussed; these are highly sensitive to minute visible changes of the ODSs. In order to enhance the sensitivity of hazard detection, the response vector assurance criterion value is computed and evaluated during operation. The capabilities and limitations of the methodology on the example of a cantilever with manually emerging damage are demonstrated.

scholarly journals Human first-order tactile neurons can resolve spatial details on the scale of single fingerprint ridges

2020 ◽  
Author(s):  
Ewa Jarocka ◽  
J Andrew Pruszynski ◽  
Roland S Johansson
Keyword(s):  
Receptive Fields ◽  
Scanning Speed ◽  
Skin Surface ◽  
Spatial Period ◽  
Tactile Information ◽  
Spatial Selectivity ◽  
First Order ◽  
Highly Sensitive ◽  
Receptor Organ

AbstractFast-adapting type 1 (FA-1) and slow-adapting type 1 (SA-1) first-order tactile neurons provide detailed spatiotemporal tactile information when we touch objects with fingertips. The distal axon of these neuron types branches in the skin and innervates many receptor organs associated with fingerprint ridges (Meissner corpuscles and Merkel cell neurite complexes, respectively), resulting in heterogeneous receptive fields that include many highly sensitive zones or ‘subfields’. Using raised dots that tangentially scanned a neuron’s receptive field, here we examined the spatial resolution capacity of FA-1 and SA-1 neurons afforded by their heterogeneous receptive fields and its constancy across scanning speed and direction. We report that the resolution of both neuron types on average corresponds to a spatial period of ∼0.4 mm and provide evidence that a subfield’s spatial selectivity arises because its associated receptor organ measures mechanical events limited to a single fingerprint ridge. Accordingly, the sensitivity topography of a neuron’s receptive fields is quite stable over repeated mappings and over scanning speeds representative of real-world hand use. The sensitivity topography is substantially conserved also for different scanning directions, but the subfields can be relatively displaced by direction-dependent shear deformations of the skin surface.Significance StatementThe branching of the distal axon of first-order tactile neurons with receptor-organs associated with fingerprint ridges (Meissner and Merkel end-organs) results in cutaneous receptive fields composed of several distinct subfields spread across multiple ridges. We show that the spatial selectivity of the subfields typically corresponds to the dimension of the ridges (∼0.4 mm) and that neurons’ subfield layout is well preserved across tangential movement speeds and directions representative of natural use of the fingertips. We submit that the receptor-organ underlying a subfield essentially measures mechanical events at an individual ridge. That neurons receive convergent input from multiple subfields does not preclude the possibility that spatial details can be resolved on the scale of single fingerprint ridges by a population code.

scholarly journals Effect of Thoracic Connective Lesion on Inter-Leg Coordination in Freely Walking Stick Insects

2021 ◽  
Vol 9 ◽  
Author(s):  
Miriam Niemeier ◽  
Manon Jeschke ◽  
Volker Dürr
Keyword(s):  
Information Exchange ◽  
Load Transfer ◽  
Legged Locomotion ◽  
Sham Operation ◽  
Spatial Coordination ◽  
Mechanical Coupling ◽  
Stick Insects ◽  
Leg Coordination ◽  
Neural Information ◽  
Walking Stick

Multi-legged locomotion requires appropriate coordination of all legs with coincident ground contact. Whereas behaviourally derived coordination rules can adequately describe many aspects of inter-leg coordination, the neural mechanisms underlying these rules are still not entirely clear. The fact that inter-leg coordination is strongly affected by cut thoracic connectives in tethered walking insects, shows that neural information exchange among legs is important. As yet, recent studies have shown that load transfer among legs can contribute to inter-leg coordination through mechanical coupling alone, i.e., without neural information exchange among legs. Since naturalistic load transfer among legs works only in freely walking animals but not in tethered animals, we tested the hypothesis that connective lesions have less strong effects if mechanical coupling through load transfer among legs is possible. To do so, we recorded protraction/retraction angles of all legs in unrestrained walking stick insects that either had one thoracic connective cut or had undergone a corresponding sham operation. In lesioned animals, either a pro-to-mesothorax or a meso-to-metathorax connective was cut. Overall, our results on temporal coordination were similar to published reports on tethered walking animals, in that the phase relationship of the legs immediately adjacent to the lesion was much less precise, although the effect on mean phase was relatively weak or absent. Lesioned animals could walk at the same speed as the control group, though with a significant sideward bias toward the intact side. Detailed comparison of lesion effects in free-walking and supported animals reveal that the strongest differences concern the spatial coordination among legs. In free walking, lesioned animals, touch-down and lift-off positions shifted significantly in almost all legs, including legs of the intact body side. We conclude that insects with disrupted neural information transfer through one connective adjust to this disruption differently if they experience naturalistic load distribution. While mechanical load transfer cannot compensate for lesion-induced effects on temporal inter-leg coordination, several compensatory changes in spatial coordination occur only if animals carry their own weight.

The Fine Structure of the Cockroach Subgenual Organ

1970 ◽  
Vol 28 ◽  
pp. 80-81
Author(s):  
David T. Moran
Keyword(s):  
Fine Structure ◽  
Circulatory System ◽  
Epidermal Cells ◽  
Mechanical Stimuli ◽  
Sense Organs ◽  
Fluid Medium ◽  
Blaberus Discoidalis ◽  
Highly Sensitive ◽  
Surrounding Fluid ◽  
Subgenual Organ

Insects are abundantly endowed with mechanoreceptors, sense organs that transduce mechanical stimuli into nerve impulses. Like most cockroaches, Blaberus discoidalis is highly sensitive to vibrations of the substrate on which it walks. This sensitivity is thought to be due in large part to the subgenual organ — an intricately constructed mechanoreceptor located near the proximal end of the tibia. The exoskeleton of the cockroach is secreted by a layer of epidermal cells which enclose the haemocoele of animal's open circulatory system. The subgenual organ is a thin, fan-shaped flap of tissue which is suspended from the epidermis and occludes much of the dorsal blood space in the hollow leg. It is therefore surrounded by blood on all sides; its position renders it susceptible to minor displacements of the surrounding fluid medium. Highly modified epidermal cells which are packed with hundreds of parallel microtubules support the subgenual organ as a ligament. The cells which compose the bulk of the organ are populated with a few mitochondria and many microtubules.

Installation of a High Sensitivity Ocean Borehole Strainmeter in the Nankai Trough Under Severe Sea Current Conditions

2018 ◽  
Vol 52 (3) ◽  
pp. 128-137
Author(s):  
Yuya Machida ◽  
Eiichiro Araki ◽  
Toshinori Kimura ◽  
Demian M. Saffer ◽  
Tomokazu Saruhashi ◽  
...  
Keyword(s):  
Nankai Trough ◽  
High Sensitivity ◽  
Recording Device ◽  
Pressure Data ◽  
Cement Slurry ◽  
Mechanical Coupling ◽  
Vortex Induced Vibrations ◽  
Highly Sensitive ◽  
Borehole Strainmeter ◽  
Vibration Tests

AbstractA high-sensitivity volumetric strainmeter has been installed into the C0010 borehole observatory using the drilling vessel (D/V) Chikyu during the Expedition 365 cruise in the Nankai Trough, Japan. At this location, crustal deformation occurs in association with large interplate earthquakes. However, strong Kuroshio ocean currents cause vortex-induced vibrations (VIVs) in the region, which can cause fatal damage to the strainmeter. Therefore, laboratory vibration tests were performed prior to installation to confirm that the antivibration mechanism inside the strainmeter was functional against the severe vibrations during installation. VIV was measured prior to installing the strainmeter into the C0010A borehole using accelerometers at the installation site. The results indicated that the VIV were within the specification of the antivibration mechanism. This meant that installation of the strainmeter into the borehole was possible. To maximize sensor sensitivity, it is extremely important to ensure mechanical coupling of the strainmeter with the borehole wall by cementing operation after installation. The cementing process was confirmed using a pressure recording device incorporated within the strainmeter. Pressure data clearly showed that seawater had been displaced with cement slurry. Data from the strainmeter clearly showed tidal waveforms, which are comparable to those of pressure data recorded by a borehole pressure sensor installed at approximately the same depth. Accuracies of the strain data were validated through the procedure. They suggest that the first installation of the ocean borehole strainmeter in the Nankai Trough was successful, and therefore, highly sensitive strain measurement is now possible in a seismically active area.

scholarly journals A muscle receptor organ in Eledone cirrhosa

1960 ◽  
Vol 39 (3) ◽  
pp. 419-431 ◽  
Author(s):  
J. S. Alexandrowicz
Keyword(s):  
Thin Layer ◽  
Close Association ◽  
Stellate Ganglion ◽  
Plexiform Layer ◽  
The Body ◽  
Muscle Fibres ◽  
Limited Area ◽  
Muscle Receptor ◽  
Receptor Organ ◽  
Proprioceptive Function

Nerve cells evidently of a sensory nature have been found in Eledone cirrhosa on the inside of the mantle in a limited area near the stellate ganglion. The cells, whose number on each side of the body is no less than 50, are in close association with a special thin layer of muscles, and obviously must have a proprioceptive function. The whole complex can therefore be regarded as a muscle receptor which from its situation may be termed the substellar organ.The muscular component of this organ consists of fibres arranged in very flat bundles which, anastomosing with one another, form a plexiform layer situated under the stellate ganglion and the stellar nerves. It may be called substellar muscle plexus (ss-plexus for short). The area occupied by it, which is roughly semicircular in shape, extends to the points where the stellar nerves penetrate the muscles or a little beyond these points (Text-fig. 1). The ss-plexus, although situated close to thecompact muscle of the mantle, does not appear to have anatomical relation with the latter; it has, however, direct connexions with strands of muscle fibres reaching theplexus from two directions. The fibres coming from the medianside belong to the muscle attaching the mantle to the visceral sac in which runs the pallial nerve (or mantle connective). This muscle, called lateral pallial adductor (see Tippmar, 1913) istwisted in such a way that its bundles coming from the anterior region of the visceral sac insert into the mantle behind the stellate ganglion, and those originating posteriorly insert in front of it.

scholarly journals Neuronal Innervation of the Subgenual Organ Complex and the Tibial Campaniform Sensilla in the Stick Insect Midleg

Insects ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 40 ◽  
Author(s):  
Johannes Strauß
Keyword(s):  
Physiological Role ◽  
Stick Insect ◽  
Campaniform Sensilla ◽  
Innervation Pattern ◽  
Branching Points ◽  
Stick Insects ◽  
Sensory Structures ◽  
Evolutionary Comparisons ◽  
Subgenual Organ

Mechanosensory organs in legs play are crucial receptors in the feedback control of walking and in the detection of substrate-borne vibrations. Stick insects serve as a model for the physiological role of chordotonal organs and campaniform sensilla. This study documents, by axonal tracing, the neural innervation of the complex chordotonal organs and groups of campaniform sensilla in the proximal tibia of the midleg in Sipyloidea sipylus. In total, 6 nerve branches innervate the different sensory structures, and the innervation pattern associates different sensilla types by their position. Sensilla on the anterior and posterior tibia are innervated from distinct nerve branches. In addition, the variation in innervation is studied for five anatomical branching points. The most common variation is the innervation of the subgenual organ sensilla by two nerve branches rather than a single one. The fusion of commonly separated nerve branches also occurred. However, a common innervation pattern can be demonstrated, which is found in >75% of preparations. The variation did not include crossings of nerves between the anterior and posterior side of the leg. The study corrects the innervation of the posterior subgenual organ reported previously. The sensory neuroanatomy and innervation pattern can guide further physiological studies of mechanoreceptor organs and allow evolutionary comparisons to related insect groups.

scholarly journals Coupling Mechanisms Between the Contralateral Legs of a Walking Insect (Carausius Morosus)

1989 ◽  
Vol 144 (1) ◽  
pp. 199-213 ◽  
Author(s):  
H. CRUSE ◽  
A. KNAUTH
Keyword(s):  
Thin Film ◽  
Horizontal Plane ◽  
Silicone Oil ◽  
The Other ◽  
Carausius Morosus ◽  
Mechanical Coupling ◽  
Stick Insects ◽  
Coupling Mechanisms

Interactions between contralateral legs of stick insects during walking were examined in the absence of mechanical coupling between the legs by studying animals walking on a horizontal plane covered with a thin film of silicone oil. Investigations of undisturbed walks showed that contralateral coupling is weaker han ipsilateral coupling. Two types of influence were found, (i) For each pair of front, middle and rear legs, when one leg started a retraction movement, the probability for the contralateral leg to start a protraction was increased, (ii) For front- and hind-leg pairs, it was found that the probability of starting a protraction in one leg was also increased, the farther the other leg was moved backwards during retraction. Whether such influences exist between middle legs could not be determined. Both ‘excitatory’ mechanisms very much resemble those influences which have been found to exist between ipsilateral legs. However, in contrast to ipsilateral legs, the interaction between two contralateral legs was found to act in both directions.

scholarly journals Behaviour and Motor Output of Stick Insects Walking on a Slippery Surface: I. Forward Walking

1983 ◽  
Vol 105 (1) ◽  
pp. 215-229 ◽  
Author(s):  
S. EPSTEIN ◽  
D. GRAHAM
Keyword(s):  
Glass Surface ◽  
Silicone Oil ◽  
Swing Phase ◽  
Motor Output ◽  
Mechanical Coupling ◽  
Stick Insects ◽  
Weak Activity ◽  
Slippery Surface ◽  
Coordination Patterns

The walking coordination and motor output of intact adult stick insects was examined when they were supported above an oiled glass surface. The viscosity of the silicone oil was adjusted so that the animal walked with either tripod or slow-walk coordination. In the absence of mechanical coupling through the substrate, the legs typically moved at different speeds in retraction. If these differences were not too large the walks were well-coordinated in the transitions from stance to swing phase. Motor output was variable and sometimes showed periods of very weak activity in depressors and retractors. Under these conditions an individual leg moved much more slowly than its neighbours, producing 2:1 coordination patterns.

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