The Effect of Labyrinthectomy on the Co-ordination of Limb Movements in the Toad

1947 ◽  
Vol 24 (1-2) ◽  
pp. 36-41
Author(s):  
J. GRAY ◽  
H. W. LISSMANN

1. After bilateral labyrinthectomy, a toad can only walk normally if the stimulus which excites it to move is applied symmetrically on the two sides of the body. If the stimulus is asymmetrical, the animal's path curves towards the unstimulated side; if the stimulus is relatively intense the animal ‘circles’ persistently towards the unstimulated side. The ambulatory response of a normal animal to an asymmetrical stimulus is dependent on both proprioceptive and labyrinthine activity. 2. After bilateral labyrinthectomy, both hindlimbs exhibit swimming movements when the animal is freely suspended in water but co-ordination between the two limbs is lost. Evidence is put forward which suggests that the swimming rhythm of the limbs may be dependent on rhythmical excitation of the membranous labyrinth. No swimming occurs when the limbs of a labyrinthectomized toad are de-afferentated. 3. The removal of both labyrinths does not abolish the power of the limbs to right the animal when placed on its back. The mechanics of the righting movement are described.

1920 ◽  
Vol 10 (2) ◽  
pp. 161-169 ◽  
Author(s):  
J. W. S. Macfie

The pupa is bilaterally symmetrical, that is, setae occur in similar situations on each side of the body, so that it will suffice to describe the arrangement on one side only. The setae on the two sides of the same pupa, however, often vary as regards their sub-divisions, and similar variations occur between different individuals; as an example, in Table I are shown some of the variations that were found in ten pupae taken at random. An examination of a larger number would have revealed a wider range. As a rule, a seta which is sometimes single, sometimes divided, is longer when single. For example, in one pupa the seta at the posterior angle ofthe seventh segment was single on the right side, double on the left; the former measuring 266μ, and the latter only 159μ in length. This fact is not specifically mentioned in the descriptions which follow, but should be understood.


1965 ◽  
Vol 209 (6) ◽  
pp. 1261-1266 ◽  
Author(s):  
Douglas Stuart ◽  
Kenneth Ott ◽  
Earl Eldred

Shivering responses to cold have been studied in 21 cats subjected to lesions or stimulation of the cerebellum. Reluctance gauges taped to the extremity were used to sense accelerations produced by the tremor. Shivering of normal pattern was recorded within hours after total extirpation of the cerebellum and up to 4 weeks after surgery. Cats with lesions restricted to the anterior lobe also demonstrated apparently normal rhythm shivering. Comparison of regularity, amplitude, and rate of limb tremor in cats with a hemicerebellectomy, or lesions of one dentate, interpositus, or fastigial nucleus failed to reveal significant differences between the two sides of the body. Single shock or repetitive stimulation of medial cerebellar sites through indwelling electrodes primarily caused suppression of the amplitude of an ongoing tremor, but only at thresholds well above those needed to cause clonic or tonic movements of the limb. It is concluded that the presence of the cerebellum is not requisite for initiation and maintenance of shivering and that this organ has little regulatory effect on the rhythmicity of shivering.


2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Mohsen Javadzadeh ◽  
Hedieh Saneifard ◽  
Amir Hossein Hosseini

Russell-Silver syndrome is a genetic disorder the inheritance pattern of which is mostly sporadic. Some of the features of the syndrome are present at birth, and others appear in later years. The main clinical features include low birth weight, poor growth postnatally, short height, and discrepancies in size between the two sides of the body Abu-Amera et al. (2008), Binder et al. (2011). There is no statistical significant difference in prevalence between males and females. We report a case of Russell-Silver syndrome with intrauterine and postnatal growth retardation, triangular face, and body asymmetry, in addition to torticollis as a novel manifestation. In neck sonography, we found asymmetry of sternocleidomastoid muscles. In conclusion, we describe torticollis as a presentation of Russell-Silver syndrome.


1903 ◽  
Vol 49 (204) ◽  
pp. 176-177
Author(s):  
J. R. Gilmour

The patient was a child of 7 years, of good family history, both direct and collateral. No other members of the family suffered from epilepsy, and there was no evidence of syphilis. Somewhat slow in development, she began to walk and speak in her fourth year. About this time she would fall down with loss of consciousness lasting from five to six minutes. Bromide diminished these attacks, but afterwards marked convulsions developed, without aura or cry, with frothing at the mouth, incontinence of urine, marked prostration, and headache. Further symptoms supervened. On examination the patient was found to be well developed and nourished. Each three or four months she suffers from the convulsive attacks previously described. Percussion of the head causes the following phenomena:—A light blow on the scalp or face without warning to the child causes either an immediate fall or sudden and very marked trembling, and movements in the upper limbs are noticed. These bear no relation to the strength of the blow, and any hurt to the body produces no effect. Methodical percussion over the motor areas does not produce any isolated contraction. There is no difference on the two sides of the cranium. Excitement increases the effects. Anæsthesia of a skin area by chloride of ethyl produces no alteration. Electrical stimulation does not influence the condition. After the fall the child arose crying and agitated, the walk was uncertain and hesitating, the arms being used to balance, and she walked zigzag, as if the power of directing herself were lost—almost like a cerebellar gait.


1965 ◽  
Vol 20 (2) ◽  
pp. 335-368 ◽  
Author(s):  
A. Jean Ayres

Analysis of test scores made by 100 children with and 50 without suspected perceptual deficits lead to hypothesizing five syndromes characteristic of dysfunction: (a) developmental apraxia, distinguished by deficits in motor planning, tactile perception and finger identification; (b) tactile, kinesthetic and visual perceptual dysfunction in form and position in space; (c) tactile defensiveness, demonstrated by hyperactive-distractible behavior, faulty tactile perception and defensive responses to tactile stimuli; (d) deficit of integration of the two sides of the body, identified by difficulty in right-left discrimination, avoidance in crossing the mid-line, and incoordinate bilateral hand movements; (e) deficit of visual figure-ground discrimination.


1914 ◽  
Vol 19 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Paul A. Lewis ◽  
Arthur Georges Margot

Infection of rats and mice with Bacillus tuberculosis (bovine type) develops a splenic tumor as a typical lesion. Removal of the spleen from mice (albino) greatly increases their resistance to the infection. This increased resistance cannot be explained at present. The infection in the splenectomized mice tends to remain localized as contrasted with an almost septicemic type of disease which is usual in the normal animal. The animals of each group that live more than thirty days are apt to present typical exudative lesions. The removal of the spleen does not therefore grossly change what may be called the capacity of the body for exudation.


2017 ◽  
Vol 836 ◽  
pp. 502-531 ◽  
Author(s):  
Rolf J. Ryham

This paper deals with the hydrodynamics of a viscous liquid passing through the hole in a deflating hollow sphere. I employ the method of complementary integrals and calculate in closed form the pressure and streamfunction for the axisymmetric, creeping motion coming from changes in radius. The resulting flow fields describe the motion of a deformable spherical cap in a viscous environment, where the deformations include changes in the size of the spherical cap, the size of the hole and translation of the body along the axis of symmetry. The calculations yield explicit expressions for the jumps in pressure and resistance coefficients for the combined deformations. The equation for the translation force shows that a freely suspended spherical cap is able to propel as an active swimmer. The expression for pressure contains the classic Sampson flow rate equation as a limiting case, but simulations show that the pressure must also account for the velocity of hole widening to correctly predict outflow rates in physiology. Movies based on the closed-form solutions visualize the flow fields and pressures as part of physical processes.


2019 ◽  
Vol 30 (6) ◽  
pp. 1393-1399
Author(s):  
Dejan Vitanski

The author of labor, through an in-depth considiration, tries to understand, capture and notify the essential elements and immanent features of the principles of hierarchy and subordination in the public administration. Administration is one of the key entities in the physiognomy of the state system. It is a complex mechanism and, in general, a hierarchically profiled structure, which forms the "spine" of the state. Hierarchy and subordination are the basic substrate of administrative architecture. In an organizational sense, the hierarchical principle is a system of eldership, whose essence is expressed in the obligation of the subordinate entity (individual or authority) to conform to the orders of the superordinate elder in a strictly formalized system of mutual relations that arise in connection with the performance of the working tasks within an organization. The hierarchical pyramid is a stratified (layered) system of functions, ranging from the more specific to the more general. Within that system, carriers of more general functions control the work of carriers of closer functions. The hierarchical structure has the form of a vertical chain, in which each higher level has authority over the lower one, and each lower level submits to the orders and the directives at the higher level. Hierarchical placement allows vertical process management, providing easier management, effective control, as well as locating the responsibility and dysfunctionality of each link in the administrative chain. According to modern understandings, which occurred with the establishment of the legal state, there is a legally established border and a demarcation line to which the elder can move when issuing specific orders to the subordinates. That limit implies that the elder can not issue orders to the subordinates. This means that in modern-established states, in which the administration is based on the pivotal principle of legality, subordination actually arises as a kind of counterbalance to the hierarchy. In accordance with the principle of subordination, when the duty of the civil servant is prescribed to perform the orders of the head of the body, as well as the orders of the immediate superior officer, it is noted that the civil servant is obliged to act upon those orders, but exclusively in accordance with the Constitution , by law or by other regulation. The fundamental dilemma that is put in front of the author of the labor and on which the focus of the scientific-research interest is placed is by determining and clarifying the essence of the principles of hierarchy and subordination, to answer the question: is the hierarchy and subordination synonyms, dichotomous categories or predestined two sides of the same medal?


Author(s):  
Archana R ◽  
Kumar Sai Sailesh ◽  
Jinu K V ◽  
Minu Johny ◽  
Varsha Varghese ◽  
...  

Vestibular framework is known as membranous labyrinth and encased in a hard waterway of fleeting bone. Invigorating this framework may deliver different remedial outcomes in the body and additionally in the psyche. Distinctive sorts of animating strategies are utilizing these days. Subsequently it is fundamental to mindful of every single accessible technique to choose conceivable strategy to hone vestibular stimulation. Here we audit significant sorts of accessible vestibular stimulation strategies.


2018 ◽  
Author(s):  
Natasha Mhatre ◽  
Senthurran Sivalinghem ◽  
Andrew C Mason

Spiders rely on mechanical vibration sensing for sexual signalling, prey capture and predator evasion. The sensory organs underlying vibration detection, called slit sensilla, resemble cracks in the spider's exoskeleton, and are distributed all over the spider body. Those crucial to sensing web- and other substrate-borne vibrations are called lyriform organs and are densely distributed around leg joints. It has been shown that forces that cause bending at leg joints also activate these lyriform organs. Little is known of how the biomechanics of the body of a freely-suspended spider in its natural posture interact with vibrations introduced into the body and how this affects vibration perception. Female black widow spiders, in particular, have a striking body-form; their long thin legs support a large pendulous abdomen. Here, we show that in their natural posture, the large abdominal mass of black widow females, interacts with the spring-like behaviour of their leg joints and determines the mechanical behaviour of different leg joints. Furthermore, we find that adopting different body postures enables females to alter both the level and tuning of the mechanical input to lyriform organs. Therefore, we suggest that posture may be used to flexibly and reversibly focus attention to different classes or components of web vibration. Postural effects thus emphasize the dynamic loop of interactions between behaviour and perception, i.e. between 'brain' and body.


Sign in / Sign up

Export Citation Format

Share Document