scholarly journals Cochlea – A Physiological Description of a Finely Structured Sense Organ

10.5772/66316 ◽  
2017 ◽  
Author(s):  
Raphael R. Ciuman
Keyword(s):  
Sense Organ

scholarly journals A Vibrissa-Inspired Highly Flexible Tactile Sensor: Scanning 3D Object Surfaces Providing Tactile Images

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1572
Author(s):  
Lukas Merker ◽  
Joachim Steigenberger ◽  
Rafael Marangoni ◽  
Carsten Behn
Keyword(s):  
Steel Wire ◽  
Sense Organ ◽  
Tactile Sensor ◽  
Tactile Sensors ◽  
Measuring Device ◽  
3D Object ◽  
Torque Transducer ◽  
Sense Of Touch ◽  
Important Basis ◽  
Support Reactions

Just as the sense of touch complements vision in various species, several robots could benefit from advanced tactile sensors, in particular when operating under poor visibility. A prominent tactile sense organ, frequently serving as a natural paragon for developing tactile sensors, is the vibrissae of, e.g., rats. Within this study, we present a vibrissa-inspired sensor concept for 3D object scanning and reconstruction to be exemplarily used in mobile robots. The setup consists of a highly flexible rod attached to a 3D force-torque transducer (measuring device). The scanning process is realized by translationally shifting the base of the rod relative to the object. Consequently, the rod sweeps over the object’s surface, undergoing large bending deflections. Then, the support reactions at the base of the rod are evaluated for contact localization. Presenting a method of theoretically generating these support reactions, we provide an important basis for future parameter studies. During scanning, lateral slip of the rod is not actively prevented, in contrast to literature. In this way, we demonstrate the suitability of the sensor for passively dragging it on a mobile robot. Experimental scanning sweeps using an artificial vibrissa (steel wire) of length 50 mm and a glass sphere as a test object with a diameter of 60 mm verify the theoretical results and serve as a proof of concept.

scholarly journals Effect of wing scalloping mutations on cut expression and sense organ differentiation in the Drosophila wing margin.

Genetics ◽  
1992 ◽  
Vol 131 (2) ◽  
pp. 353-363 ◽  
Author(s):  
J Jack ◽  
Y DeLotto
Keyword(s):  
Sense Organ ◽  
Epidermal Cells ◽  
Additive Effect ◽  
Mutant Phenotype ◽  
Wing Margin ◽  
Transcriptional Enhancer ◽  
Organ Differentiation ◽  
Notch Activity ◽  
Neural Fate ◽  
Drosophila Wing

Abstract A number of wing scalloping mutations have been examined to determine their effects on the mutant phenotype of cut mutations and on the expression of the Cut protein. The mutations fall into two broad classes, those which interact synergistically with weak cut wing mutations to produce a more extreme wing phenotype than either mutation alone and those that have a simple additive effect with weak cut wing mutations. The synergistically interacting mutations are alleles of the Notch, Serrate and scalloped genes. These mutations affect development of the wing margin in a manner similar to the cut wing mutations. The mutations inactivate the cut transcriptional enhancer for the wing margin mechanoreceptors and noninnervated bristles and prevent differentiation of the organs. Surprisingly, reduction of Notch activity in the wing margin does not have the effect of converting epidermal cells to a neural fate as it does in other tissues of ectodermal origin. Rather, it prevents the differentiation of the wing margin mechanoreceptors and noninnervated bristles.

The Lever, or How to Act at a Distance: A Backdrop to Theophrastus’ De sensibus

Rhizomata ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 168-187
Author(s):  
André Laks
Keyword(s):  
Present Article ◽  
Sense Organ ◽  
Sense Perception ◽  
De Anima ◽  
Extreme Caution ◽  
Alexander Of Aphrodisias ◽  
Physiological Alteration ◽  
Material Process ◽  
Theoretical Frame

AbstractIt is well known that when it comes to perception in the De anima, Aristotle uses affection-related vocabulary with extreme caution. This has given rise to a debate between interpreters who hold that in Aristotle’s account, the act of sense-perception nevertheless involves the physiological alteration of the sense organ (Richard Sorabji), and those think, with Myles Burnyeat, that for Aristotle, perception does not involve any material process, so that an Aristotelian physics of sense-perception is a “physics of forms alone”. The present article suggests that the dematerialisation of Aristotle’s theory of perception, which has a long story from Alexander of Aphrodisias to Brentano, may be in fact traced back to Theophrastus’ exegesis of Aristotle’s relevant passages in the De anima in his Physics, as we can reconstruct it on the basis of Priscian’s Metaphrasis in Theophrastum and Simplicius’ commentary of Aristotle’s De Anima. The reconstruction also provides a scholastic-theoretical frame to Theophrastus’ critical exposition of ancient theories about sense perception in his De sensibus, whether or not the discussion originally belonged to Theophrastus’ Physics.

Peripheral control of the gain of a central synaptic connection between antagonistic motor neurones in the locust

1996 ◽  
Vol 199 (3) ◽  
pp. 613-625
Author(s):  
T Jellema ◽  
W Heitler
Keyword(s):  
Muscle Contraction ◽  
Sensory Input ◽  
Sense Organ ◽  
Gain Control ◽  
Motor Neurone ◽  
Extensor Muscle ◽  
Chordotonal Organ ◽  
Excitatory Postsynaptic Potential ◽  
Motor Neurones ◽  
Peripheral Sensory

The metathoracic fast extensor tibiae (FETi) motor neurone of locusts is unusual amongst insect motor neurones because it makes output connections within the central nervous system as well as in the periphery. It makes excitatory chemical synaptic connections to most if not all of the antagonist flexor tibiae motor neurones. The gain of the FETi-flexor connection is dependent on the peripheral conditions at the time of the FETi spike. This dependency has two aspects. First, sensory input resulting from the extensor muscle contraction can sum with the central excitatory postsynaptic potential (EPSP) to augment its falling phase if the tibia is restrained in the flexed position (initiating a tension-dependent reflex) or is free to extend (initiating a movement-dependent resistance reflex). This effect is thus due to simple postsynaptic summation of the central EPSP with peripheral sensory input. Second, the static tibial position at the time of the FETi spike can change the amplitude of the central EPSP, in the absence of any extensor muscle contraction. The EPSP can be up to 30 % greater in amplitude if FETi spikes with the tibia held flexed rather than extended. The primary sense organ mediating this effect is the femoral chordotonal organ. Evidence is presented suggesting that the mechanism underlying this change in gain may be specifically localised to the FETi-flexor connection, rather than being due to general position-dependent sensory feedback summing with the EPSP. The change in the amplitude of the central EPSP is probably not caused by general postsynaptic summation with tonic sensory input, since a diminution in the amplitude of the central EPSP caused by tibial extension is often accompanied by overall tonic excitation of the flexor motor neurone. Small but significant changes in the peak amplitude of the FETi spike have a positive correlation with changes in the EPSP amplitude, suggesting a likely presynaptic component to the mechanism of gain control. The change in amplitude of the EPSP can alter its effectiveness in producing flexor motor output and, thus, has functional significance. The change serves to augment the effectiveness of the FETi-flexor connection when the tibia is fully flexed, and thus to increase its adaptive advantage during the co-contraction preceding a jump or kick, and to reduce the effectiveness of the connection when the tibia is partially or fully extended, and thus to reduce its potentially maladaptive consequences during voluntary extension movements such as thrusting.

Ultrastructure of the osphradium of the Tertiary relict snail, Campanile symbolicum Iredale (Mollusca, Streptoneura)

1992 ◽  
Vol 337 (1282) ◽  
pp. 457-469 ◽  
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Sense Organ ◽  
Central Zone ◽  
Structural Data ◽  
Structural Features ◽  
Sensory Epithelium ◽  
Sensory Cells ◽  
Cell Type ◽  
Sensory Cilia ◽  
A Cell

The osphradium of Campanile symbolicum Iredale, 1917 is a gill-like, bipectinate sense organ, which is located at the left side of the mantle roof. The mass of the deeply clefted sensory epithelium of the leaflets is built up by sensory cells, which are provided with deeply invaginated aberrant cilia and large cytosomes containing pigment formations. In addition, many free nerve processes are present, bearing a single or few sensory cilia with accessory centrioles. Polyciliary cells are interspersed. A cell type with netlike or concentrically arranged smooth endoplasmic reticulum is commonly found near the central axis of the osphradium . The central zone of each leaflet includes nervous tissue and a complicated muscular grid, with pore cells and fibroblasts also present. Based on the fine-structural data the functional and ecological significance of the osphradium of Campanile symbolicum is discussed. The com bination of herbivory and a lamellar osphradium is rare among the Gastropoda, suggesting that the osphradium of Campanile might also be involved in reproductive biology. Many fine-structural features of the osphradium of Campanile symbolicum are unique among the gastropods and reflect the phylogenetic isolation of this relict snail. The net-like cell type, however, is probably homologous with the so-called Si4 cell in the rem aining caenogastropods, for which a largely different osphradial fine-structure is diagnostic. The affinities of Campanile symbolicum are probably closer to the Caenogastropoda than to the Allogastropoda and Euthyneura. With present knowledge it might be best classified near the base or even as the first clade within the Caenogastropoda.

scholarly journals Selective lineage specification by mab-19 during Caenorhabditis elegans male peripheral sense organ development.

Genetics ◽  
1994 ◽  
Vol 138 (3) ◽  
pp. 675-688 ◽  
Author(s):  
M E Sutherlin ◽  
S W Emmons
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Fate ◽  
Physiological Stress ◽  
Developmental Regulation ◽  
Cell Lineage ◽  
Sense Organ ◽  
Sensory Ray ◽  
Hypodermal Cell ◽  
Physiological Stress Response ◽  
Male Specific

Abstract The action of the gene mab-19 is required for specification of a subset of Caenorhabditis elegans male peripheral sense organ (ray) lineages. Two mab-19 alleles, isolated in screens for ray developmental mutations, resulted in males that lacked the three most posterior rays. Cell lineage alterations of male-specific divisions of the most posterior lateral hypodermal (seam) blast cell, T, resulted in the ray loss phenotype in mab-19 mutant animals. Postembryonic seam lineage defects were limited to male-specific T descendent cell divisions. Embryonic lethality resulted when either mab-19 mutation was placed over a chromosomal deficiency encompassing the mab-19 locus. The earliest detectable defect was aberrant hypodermal cell movements during morphogenesis. From these data, it is inferred that both mab-19 alleles described are hypomorphs, and further reduction of mab-19 function results in embryos that are unable to complete morphogenesis. Thus, mab-19 may play a larger role in developmental regulation of hypodermal cell fate, including sensory ray development in males. Body morphology mutations, passage through the dauer stage, and heat or CdCl2 treatment suppressed mab-19 male phenotypes. A model is presented in which all three types of suppression result in a physiological stress response, which in turn leads to correction of the mab-19 defect.

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