Rhythmicity in the early swimming of anuran larvae

Development ◽  
1964 ◽  
Vol 12 (4) ◽  
pp. 665-671
Author(s):  
Michael Corner
Keyword(s):  
Tactile Stimulation ◽  
Extensive Study ◽  
The Body ◽  
Quantitative Characterization ◽  
Anatomical Basis ◽  
The Central Nervous System ◽  
Two Sides ◽  
The Waves ◽  
Made In

Previous observations of the development of somatic movements in amphibians concentrated their attention on ‘reflex’ mechanisms (for review, see Hooker, 1952). Extensive study has been made of the types of movement evoked by tactile stimulation at different stages in early development and on the anatomical basis for such responses. Emphasis was thus placed upon the formation of direct pathways through the central nervous system from receptor to effector. For the swimming movements, this approach was able to account for (a) the cranio-caudal wave of somite contractions, in response to sensory input from any part of the body surface, and (b) the existence of a phase difference between the waves on the two sides of the body. A quantitative characterization of behavior at successive stages has also been made, in terms of the distances travelled per response (cf. Detwiler, 1948; Sladeček, 1960).

Characterization of Myoelectric Signals Using System Identification Techniques

2004 ◽  
Author(s):  
Jeffrey T. Bingham ◽  
Marco P. Schoen
Keyword(s):  
System Identification ◽  
Motor Neurons ◽  
Current System ◽  
Electrical Potential ◽  
Computer Software ◽  
The Body ◽  
Myoelectric Signals ◽  
Hand Motion ◽  
The Central Nervous System

Human muscle motion is initiated in the central nervous system where a nervous signal travels through the body and the motor neurons excite the muscles to move. These signals, termed myoelectric signals, can be measured on the surface of the skin as an electrical potential. By analyzing these signals it is possible to determine the muscle actions the signals elicit, and thus can be used in manipulating smart prostheses and teleoperation of machinery. Due to the randomness of myoelectric signals, identification of the signals is not complete, therefore the goal of this project is to complete a study of the characterization of one set of hand motions using current system identification methods. The gripping motion of the hand and the corresponding myoelectric signals are measured and the data captured with a personal computer. Using computer software the captured data are processed and finally subjected to several system identification routines. Using this technique it is possible to construct a mathematical model that correlates the myoelectric signals with the matching hand motion.

The locust jump. I. The motor programme

1977 ◽  
Vol 66 (1) ◽  
pp. 203-219
Author(s):  
W. J. Heitler ◽  
M. Burrows
Keyword(s):  
High Frequency ◽  
Tactile Stimulation ◽  
The Body ◽  
Flexor Muscle ◽  
Tactile Stimuli ◽  
Extensor Muscles ◽  
Trigger Activity ◽  
Three Stages ◽  
Motor Programme ◽  
Made In

A motor programme is described for defensive kicking in the locust which is also probably the programme for jumping. The method of analysis has been to make intracellular recordings from the somata of identified motornuerones which control the metathoracic tibiae while defensive kicks are made in response to tactile stimuli. Three stages are recognized in the programme. (1) Initial flexion of the tibiae results from the low spike threshold of tibial flexor motorneurones to tactile stimulation of the body. (2) Co-contraction of flexor and extensor muscles followa in which flexor and extensor excitor motoneurones spike at high frequency for 300-600 ms. the tibia flexed while the extensor muscle develops tension isometrically to the level required for a kick or jump. (3) Trigger activity terminates the co-contraction by inhibiting the flexor excitor motorneurones and simultaneously exciting the flexor inhibitors. This causes relaxation of the flexor muscle and allows the tibiae to extend. If the trigger activity does not occur, the jump or kick is aborted, and the tibiae remain flexed.

scholarly journals Molecular and functional characterization of somatostatin-type signalling in a deuterostome invertebrate

Open Biology ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 200172
Author(s):  
Ya Zhang ◽  
Luis Alfonso Yañez Guerra ◽  
Michaela Egertová ◽  
Cleidiane G. Zampronio ◽  
Alexandra M. Jones ◽  
...  
Keyword(s):  
Functional Characterization ◽  
The Body ◽  
Pharmacological Characterization ◽  
Cardiac Stomach ◽  
Physiological Processes ◽  
Pharmacological Tests ◽  
The Central Nervous System

Somatostatin (SS) and allatostatin-C (ASTC) are structurally and evolutionarily related neuropeptides that act as inhibitory regulators of physiological processes in mammals and insects, respectively. Here, we report the first molecular and functional characterization of SS/ASTC-type signalling in a deuterostome invertebrate—the starfish Asterias rubens (phylum Echinodermata). Two SS/ASTC-type precursors were identified in A. rubens (ArSSP1 and ArSSP2) and the structures of neuropeptides derived from these proteins (ArSS1 and ArSS2) were analysed using mass spectrometry. Pharmacological characterization of three cloned A. rubens SS/ASTC-type receptors (ArSSR1–3) revealed that ArSS2, but not ArSS1, acts as a ligand for all three receptors. Analysis of ArSS2 expression in A. rubens using mRNA in situ hybridization and immunohistochemistry revealed stained cells/fibres in the central nervous system, the digestive system (e.g. cardiac stomach) and the body wall and its appendages (e.g. tube feet). Furthermore, in vitro pharmacological tests revealed that ArSS2 causes dose-dependent relaxation of tube foot and cardiac stomach preparations, while injection of ArSS2 in vivo causes partial eversion of the cardiac stomach. Our findings provide new insights into the molecular evolution of SS/ASTC-type signalling in the animal kingdom and reveal an ancient role of SS-type neuropeptides as inhibitory regulators of muscle contractility.

Memoirs: On the Tracheal System of Collembola, with special reference to that of Sminthurus viridis, Lubb

1927 ◽  
Vol s2-71 (281) ◽  
pp. 15-30
Author(s):  
W. MALDWYN DAVIES
Keyword(s):  
Special Reference ◽  
Extensive Study ◽  
The Body ◽  
Anterior Region ◽  
Single Pair ◽  
Tracheal System ◽  
General Plan ◽  
Constant Feature ◽  
Two Sides ◽  
Unique Condition

1. No extensive study of the tracheal system of Collembola has previously been made. 2. The general plan of the tracheae has been worked out on Sminthurus viridis; two independent systems exist. 3. The presence of only a single pair of spiracles constitutes a unique condition among adult insects. The position of these is in the anterior region of the prothorax, and not in the head or cervicum as previously believed. The structure of the spiracles is extremely primitive and they possess no closing apparatus. 4. The tracheae branch dichotomously, but no anastomosis exists between the systems of the two sides of the body. Taenidia are present, but no ‘transition cells’ have been observed and the fine tracheae terminate in unbranched tracheoles. 5. The initial entrance of air into the tracheae is through the spiracles; the displacement of fluid is very slow and the whole system is not completely filled with air until about fourteen days after emergence from the egg. 6. Tracheae are found to be a constant feature in all members of the Sminthurinae examined. 7. Various methods of technique adopted are given.

Development and characterization of bio-composites using senegalia catechu resin

2021 ◽  
pp. 096739112110542
Author(s):  
Vinayagamoorthy R ◽  
Venkatakoteswararao G
Keyword(s):  
Thermal Characterization ◽  
Extensive Study ◽  
Positive Sign ◽  
Impact Loads ◽  
Synthetic Resin ◽  
Structural Investigations ◽  
Light Load ◽  
Mechanical Strengths ◽  
Made In

Owing to the increase in demand on bio-degradable materials, the present researches focus on the development of materials with full degradability. This research is intended to develop a bio-resin–based composite from senegalia catechu gum for light load automotive applications. The bio-resin obtained from the plant is processed with commercial polyester in order to make it as a functional resin for composite preparation. The synthesized resin is made in the form of structural materials by adding jute reinforcements in varying proportions. An extensive study on the various characters in comparison with the synthetic resin–based composites has been done which includes mechanical strengths analysis and thermal characters investigation. It is revealed that the bio-resin–based composites are good against tensile, flexural and impact loads as compared to that of the synthetic resin composites. In addition, it has been witnessed that the material with 40% weight of jute fabric is apt for offering highest resistance against tensile, flexural and impact loads. Micro-structural investigations proved that the bio-resin–based composites are superior in reducing the flaws and enhancing the bonding of resin with fibres as compared to that of the synthetic resin-based composites. Further, the thermal characterization showed that the bio-resin–based composites have high thermal stability as compared to the synthetic composites, and hence, a positive sign is obtained for bio-resin–based composites in both mechanical and thermal characters.

A STUDY OF THE MECHANISMS INVOLVED IN THE PRODUCTION OF IODINE-DEFICIENCY GOITER

1965 ◽  
Vol 49 (4) ◽  
pp. 610-628 ◽  
Author(s):  
Hugo Studer ◽  
Monte A. Greer
Keyword(s):  
Iodine Deficiency ◽  
Elevated Serum ◽  
Extensive Study ◽  
The Body ◽  
Total Evidence ◽  
High Iodine ◽  
Tsh Secretion ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Made In

ABSTRACT An extensive study of the temporal sequence of changes in thyroid function after initiation of a low iodine regimen has been made in rats. Variables measured include: thyroid weight, 131I uptake, monoiodotyrosine/diiodotyrosine (MIT/DIT) and triiodothyronine/thyroxine (T3/T4) ratios, iodide clearance, and 127I content. Also measured were protein-bound iodine (PBI), inorganic iodide and thyrotrophin (TSH) levels in the serum. Significant thyroid hypertrophy was produced during the first week and before there was a fall in serum PBI. Temporally related to the appearance of goiter were a rise in 131I uptake, MIT/DIT ratio and iodide clearance and a fall in thyroidal 127I concentration. In contrast, a fall in total thyroidal 127I appeared later and was closely correlated with a decline in serum PBI concentration and a rise in the thyroidal T3/T4 ratio. Manipulations such as hypophysectomy, injections of iodide, thyroxine or TSH, and refeeding a high iodine diet gave results consistent with the view that changes produced by iodine deficiency involve both autonomous and TSH-dependent thyroidal mechanisms. Although elevated serum TSH levels could not be demonstrated until after the first week of the iodine-deficient regimen, the total evidence of these studies permits the conclusion that increased TSH secretion is the most important factor in producing the thyroidal response to iodine deficiency. It is shown that homeostatic mechanisms allow maintenance of a normal level of circulating thyroid hormone in an iodine-deficient state until the body iodine pool becomes too severely depleted to supply adequate iodide substrate to the thyroid. The changes observed closely resemble those found in human iodine-deficient goiters. Although the large goiters produced after several weeks of an iodine-deficient regimen were hyperplastic, they could readily be converted to typical colloid goiters by feeding a high iodine diet for a few days.

The action of waving cylindrical tails in propelling microscopic organisms

1952 ◽  
Vol 211 (1105) ◽  
pp. 225-239 ◽  
Keyword(s):  
Lateral Displacement ◽  
Spiral Waves ◽  
Point Of View ◽  
The Body ◽  
Rubber Tube ◽  
Flexible Cylinder ◽  
Applied Torque ◽  
The Waves ◽  
Surrounding Fluid ◽  
Made In

The action of the tail of a spermatozoon is discussed from the hydrodynamical point of view. The tail is assumed to be a flexible cylinder which is distorted by waves of lateral displacement propagated along its length. The resulting stress and motion in the surrounding fluid is analyzed mathematically. Waves propagated backwards along the tail give rise to a forward motion with velocity proportional to the square of the ratio of the amplitude of the waves to their length. The rate at which energy must be supplied to maintain the waves against the reaction of the surrounding fluid is calculated. Similar calculations for the case when waves of lateral displacement are propagated as spirals show that the body is propelled at twice the speed given it by waves of the same amplitude when the motion is confined to an axial plane. An externally applied torque is necessary to prevent the reaction of the fluid due to spiral waves from causing the cylinder to rotate. This is remarkable because the cylinder itself does not rotate. A working model of a spermatozoon was made in which spiral waves could travel down a thin rubber tube without rotating it. The torque just referred to was observed and was balanced by an eccentric weight. The performance of the model while swimming freely in glycerine was compared with the calculations. The calculated speed of the model was higher than was observed, but this discrepancy could be accounted for by the fact that the model has a body containing its motive power while the calculations refer to a disembodied tail.

scholarly journals Towards the quantitative characterization of piglets’ robustness to weaning: A modelling approach

2018 ◽  
Author(s):  
M. Revilla ◽  
N.C. Friggens ◽  
L.-P. Broudiscou ◽  
G. Lemonnier ◽  
F. Blanc ◽  
...  
Keyword(s):  
Body Weight ◽  
Time Windows ◽  
Live Weight ◽  
The Body ◽  
Model Parameters ◽  
Antibiotic Administration ◽  
Quantitative Characterization ◽  
Weight Trajectories ◽  
Modelling Approach

AbstractWeaning is a critical transition phase in swine production in which piglets must cope with different stressors that may affect their health. During this period, the prophylactic use of antibiotics is still frequent to limit piglet morbidity, which raises both economic and public health concerns such as the appearance of antimicrobial-resistant microbes. With the interest of developing tools for assisting health and management decisions around weaning, it is key to provide robustness indexes that inform on the animals capacity to endure the challenges associated to weaning. This work aimed at developing a modelling approach for facilitating the quantification of piglet resilience to weaning. We monitored 325 Large White pigs weaned at 28 days of age and further housed and fed conventionally during the post-weaning period without antibiotic administration. Body weight and diarrhoea scores were recorded before and after weaning, and blood was sampled at weaning and one week later for collecting haematological data. We constructed a dynamic model based on the Gompertz-Makeham law to describe live weight trajectories during the first 75 days after weaning following the rationale that the animal response is partitioned in two time windows (a perturbation and a recovery window). Model calibration was performed for each animal. Our results show that the transition time between the two time windows, as well as the weight trajectories are characteristic for each individual. The model captured the weight dynamics of animals at different degrees of perturbation, with an average coefficient of determination of 0.99, and a concordance correlation coefficient of 0.99. The utility of the model is that it provides biological parameters that inform on the amplitude and length of perturbation, and the rate of animal recovery. Our rationale is that the dynamics of weight inform on the capability of the animal to cope with the weaning disturbance. Indeed, there were significant correlations between model parameters and individual diarrhoea scores and haematological traits. Overall, the parameters of our model can be useful for constructing weaning robustness indexes by using exclusively the growth curves. We foresee that this modelling approach will provide a step forward in the quantitative characterization of robustness.ImplicationsThe quantitative characterization of animal robustness at weaning is a key step for management strategies to improve health and welfare. This characterization is also instrumental for the further design of selection strategies for productivity and robustness. Within a precision livestock farming optic, this study develops a mathematical modelling approach to describe the body weight of piglets from weaning with the rationale that weight trajectories provide central information to quantify the capability of the animal to cope with the weaning disturbance.

scholarly journals Higher-order thalamic implication in the processing of bilateral sensory events

2020 ◽  
Author(s):  
Carlos Castejon ◽  
Angel Nuñez
Keyword(s):  
Tactile Stimulation ◽  
Thalamic Nucleus ◽  
Higher Order ◽  
The Body ◽  
Tactile Information ◽  
Whisker Pad ◽  
Two Sides ◽  
Perceptual Function ◽  
Stimulation Of

AbstractIn the rodent whisker system, it is well assumed that VPM and POm encode stimulations of the contralateral whisker pad. However, during tactile exploration whiskers are usually stimulated bilaterally. Accordingly, the integration of tactile information from the two sides of the body seems to be fundamental in the processing of these events. Here, to investigate whether POm could be able to codify these bilateral dynamics, whisker-evoked responses in this thalamic nucleus were examined by in vivo extracellular recordings in anesthetized rats using contralateral and ipsilateral stimuli. Strikingly, we found that POm is also able to respond to tactile stimulation of ipsilateral whiskers. Our findings reveal the implication of POm in the representation of bilateral tactile events by integrating simultaneous signals arising from both whisker pads and demonstrate the implication of the higher-order sensory thalamus in the encoding of bilateral sensory events. This can have important implications in bilateral perceptual function.

Muscular Tone at Rest: Relationship with Cutaneous Pleasurable Experience, an Interpretation According to the Dimensional Approach to Cerebral Dominance

1983 ◽  
Vol 57 (1) ◽  
pp. 187-198 ◽  
Author(s):  
Vezio Ruggieri ◽  
Nicoletta Sabatini ◽  
Maria Milizia
Keyword(s):  
Tactile Stimulation ◽  
Cerebral Dominance ◽  
The Body ◽  
Muscular System ◽  
Dimensional Approach ◽  
Muscular Tone ◽  
Long Latency ◽  
The Right ◽  
The Relationship ◽  
Two Sides

This study examined some aspects of the relationship between muscular tone at rest and a particular kind of pleasurable tactile stimulation (tickle) in the light of the dimensional approach to cerebral dominance. Electromyographic scores, latencies, and tickle durations for six muscles and corresponding skin areas were taken both on the right and left sides of the body from 40 female students in psychology. There was an inverse relationship between muscular tone at rest and sensitivity to tickle stimulation, which is lower (long latency and brief duration of perception) when the levels of muscular tone increase. So we hypothesize that the muscular system (especially because the correlations of tone and latency are positive) plays a role through the afferents of inhibition of tactile pleasurable experience. This role is more evident for the left side of the body. The dimensional approach to cerebral dominance on the basis of myographic score identified three groups of subjects (right, left, and non-dominant). The subjects classified as right-dominant on the basis of myographic score show a longer duration of tickle on the right half of the body than on the left and longer latency on the left. The left-dominant subjects do not show any difference between the two halves of the body in duration of tickle but show longer latency on the left side. The non-dominant subjects show also no difference between the two sides of the body for both tickle duration and latency.

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