Spatial orientation in the lamprey. II. Visual influence on orientation during locomotion and in the attached state

1995 ◽  
Vol 198 (3) ◽  
pp. 675-681
Author(s):  
F Ullén ◽  
T G Deliagina ◽  
G N Orlovsky ◽  
S Grillner
Keyword(s):  
Visual Stimulation ◽  
Video Recording ◽  
Light Response ◽  
Longitudinal Axis ◽  
Vestibular Stimulation ◽  
Dorsal Side ◽  
Transverse Plane ◽  
The Body ◽  
Negative Phototaxis ◽  
Contralateral Eye

The responses of attached lampreys to homogeneous visual stimulation and the role of visual stimuli in orientation during locomotion were investigated. Experiments were performed by video recording the responses of intact and lesioned animals to illumination. The following results were obtained. 1. In lampreys attached with their sucker mouth to the bottom of the aquarium, illumination of one eye evoked several possible motor responses (ordered after mean latency): (a) movement of the illuminated eye downwards, and the contralateral eye upwards; (b) rotation of the body around the longitudinal axis, with the illuminated side tilting downwards; (c) deviation of the caudal part of the anterior dorsal fin in the contralateral direction (away from the light); and (d) flexion of the neck and body towards the side of illumination. 2. Illumination of one eye in attached lampreys often resulted in detachment and subsequent movement in a direction away from the light source (negative phototaxis). This response was not related to the degree of roll tilt before detachment, so the negative phototaxis does not appear to be a consequence of the vestibular stimulation. 3. Negative phototaxis was also seen during locomotion: lampreys turned through 180 ° when they approached a brightly illuminated area. Photostimulation also affected their orientation in the transverse plane during swimming. Illumination of one eye from the side induced a roll movement, so that the illuminated side tilted downwards and the dorsum of the lamprey became turned towards the light. This is similar to the 'dorsal light response' of fish and shows that vision also plays a role in postural control in lampreys. 4. The behaviour of blinded animals differed strikingly from that of intact ones. Whereas intact animals preferentially swam close to the bottom, along horizontal trajectories, blinded animals showed episodes of continuous swimming upwards, near the water surface. During horizontal swimming, their orientation in the transverse plane remained normal, with the dorsal side up.

Responses of Reticulospinal Neurons in the Lamprey to Lateral Turns

2007 ◽  
Vol 97 (1) ◽  
pp. 512-521 ◽  
Author(s):  
A. Karayannidou ◽  
P. V. Zelenin ◽  
G. N. Orlovsky ◽  
T. G. Deliagina
Keyword(s):  
Spinal Cord ◽  
Vestibular Stimulation ◽  
External Factors ◽  
Gravity Vector ◽  
Negative Phototaxis ◽  
Vestibular Reflexes ◽  
Reticulospinal Neurons ◽  
Reference Direction ◽  
Implanted Electrodes ◽  
Contralateral Eye

When swimming, the lamprey maintains a definite orientation of its body in the vertical planes, in relation to the gravity vector, as the result of postural vestibular reflexes. Do the vestibular-driven mechanisms also play a role in the control of the direction of swimming in the horizontal (yaw) plane, in which the gravity cannot be used as a reference direction? In the present study, we addressed this question by recording responses to lateral turns in reticulospinal (RS) neurons mediating vestibulospinal reflexes. In intact lampreys, the activity of axons of RS neurons was recorded in the spinal cord by implanted electrodes. Vestibular stimulation was performed by periodical turns of the animal in the yaw plane (60° peak to peak). It was found that the majority of responding RS neurons were activated by the contralateral turn. By removing one labyrinth, we found that yaw responses in RS neurons were driven mainly by input from the contralateral labyrinth. We suggest that these neurons, when activated by the contralateral turn, will elicit the ipsilateral turn and thus will compensate for perturbations of the rectilinear swimming caused by external factors. It is also known that unilateral eye illumination elicits a contralateral turn in the yaw plane (negative phototaxis). We found that a portion of RS neurons were activated by the contralateral eye illumination. By eliciting an ipsilateral turn, these neurons could mediate the negative phototaxis.

scholarly journals Use of galvanic vestibular feedback to control postural orientation in decerebrate rabbits

2012 ◽  
Vol 107 (11) ◽  
pp. 3020-3026 ◽  
Author(s):  
P. V. Zelenin ◽  
L.-J. Hsu ◽  
G. N. Orlovsky ◽  
T. G. Deliagina
Keyword(s):  
Balance Control ◽  
Simple Algorithm ◽  
Vestibular Stimulation ◽  
Dorsal Side ◽  
The Body ◽  
Body Sway ◽  
Lateral Stability ◽  
Postural Perturbation ◽  
Lateral Body ◽  
Postural System

In quadrupeds, the dorsal-side-up body orientation during standing is maintained due to a postural system that is driven by feedback signals coming mainly from limb mechanoreceptors. In caudally decerebrated (postmammillary) rabbits, the efficacy of this system is considerably reduced. In this paper, we report that the efficacy of postural control in these animals can be restored with galvanic vestibular stimulation (GVS) applied transcutaneously to the labyrinths. In standing intact rabbits, GVS causes a lateral body sway towards the positive electrode. We used this GVS-caused sway to counteract the lateral body sway resulting from a mechanical perturbation of posture. Experiments were performed on postmammillary rabbits that stood on the tilting platform with their hindlimbs. To make the GVS value dependent on the postural perturbation (i.e., on the lateral body sway caused by tilt of the platform), an artificial feedback loop was formed in the following ways: 1) Information about the body sway was provided by a mechanical sensor; 2) The GVS current was applied when the sway exceeded a threshold value; the polarity of the current was determined by the sway direction. This simple algorithm allowed the “hybrid” postural system to maintain the dorsal-side-up orientation of the hindquarters when the platform was tilted by ± 20°. Thus, an important postural function, i.e., securing lateral stability during standing, can be restored in decerebrate rabbits with the GVS-based artificial feedback. We suggest that such a control system can compensate for the loss of lateral stability of various etiologies, and can be used for restoration of balance control in patients with impaired postural functions.

scholarly journals How virtual avatar experience interplays with self-concepts: the use of anthropometric 3D body models in the visual stimulation process

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Juyeon Park ◽  
Jennifer Paff Ogle
Keyword(s):  
Body Image ◽  
Visual Stimulation ◽  
The Body ◽  
Control Group ◽  
Body Perception ◽  
Self Compassion ◽  
Quantitative Results ◽  
Novel Applications ◽  
Experimental Group ◽  
Virtual Avatar

AbstractWe explored how viewing one’s anthropometric virtual avatar would affect the viewer’s self-body perception through the comparative evaluation of self-concepts—self-esteem and self-compassion, within the framework of allocentric lock theory. We recruited 18 female adults, aged 18–21, who identified themselves to have some level of body image concerns, and who had had no clinical treatment for their body image. Participants were randomly assigned either to the experimental or control group. The experimental group participated in both body positivity program and virtual avatar program, whereas the control group attended the body positivity program, only. The results affirmed that the body positivity program served as a psychological buffer prior to the virtual avatar stimulus. After the virtual avatar experience, the participants demonstrated self-acceptance by lowering their expectation on how they should look like. The findings from exit interviews enriched the quantitative results. This study verified the mechanism of the altered processing of the stored bodily memory by the egocentric sensory input of virtual avatars, and offered practical potential of the study outcomes to be applied in various emerging fields where novel applications of virtual 3D technology are sought, such as fashion e-commerce.

The Effect of Head Tilt on Perception of Self-Orientation While in a Greater than One G Environment

1995 ◽  
Vol 5 (1) ◽  
pp. 1-17
Author(s):  
Tamara L. Chelette ◽  
Eric J. Martin ◽  
William B. Albery
Keyword(s):  
Dynamic Environment ◽  
Head Tilt ◽  
Nonlinear Function ◽  
Longitudinal Axis ◽  
Multiple Regression Model ◽  
The Body ◽  
Hand Position ◽  
Haptic Information ◽  
Perception Of Self ◽  
Constant Head

The effect of head tilt on the perception of self-orientation while in a greater than one G environment was studied in nine subjects using the Armstrong Laboratory Dynamic Environment Simulator. After a 12-s stabilization period at a constant head tilt and G level, subjects reported their perception of the horizon by placing their right hand in a position they believed to be horizontal. Head tilt conditions ranged from -30° to +45° pitch over each of three head yaw positions. G levels ranged from one to four and were in the longitudinal axis of the body (Gz). Hand position was recorded in both the pitch and roll body axes. A function of head tilt did improve the fit of a multiple regression model to the collected data in both the pitch and roll axes (P < .05). The best fit was accomplished with a nonlinear function of G and head pitch. When the head remained level but the environment tilted with respect to the G vector (at angles similar to those perceived during head tilt), subjects accurately reported the environmental tilt. Head tilt under G can result in vestibular-based illusionary perception of environmental tilt. Actual environmental tilt is accurately perceived due to added channels of haptic information.

Visual Pathways for Postural Control and Negative Phototaxis in Lamprey

1997 ◽  
Vol 78 (2) ◽  
pp. 960-976 ◽  
Author(s):  
Fredrik Ullén ◽  
Tatiana G. Deliagina ◽  
Grigori N. Orlovsky ◽  
Sten Grillner
Keyword(s):  
Spinal Cord ◽  
Postural Control ◽  
Brain Stem ◽  
Light Response ◽  
Contralateral Side ◽  
Visual Pathways ◽  
Negative Phototaxis ◽  
Intact Side ◽  
Roll Control ◽  
The Brain

Ullén, Fredrik, Tatiana G. Deliagina, Grigori N. Orlovsky, and Sten Grillner. Visual pathways for postural control and negative phototaxis in lamprey. J. Neurophysiol. 78: 960–976, 1997. The functional roles of the major visuo-motor pathways were studied in lamprey. Responses to eye illumination were video-recorded in intact and chronically lesioned animals. Postural deficits during spontaneous swimming were analyzed to elucidate the roles of the lesioned structures for steering and postural control. Eye illumination in intact lampreys evoked the dorsal light response, that is, a roll tilt toward the light, and negative phototaxis, that is a lateral turn away from light, and locomotion. Complete tectum-ablation enhanced both responses. During swimming, a tendency for roll tilts and episodes of vertical upward swimming were seen. The neuronal circuitries for dorsal light response and negative phototaxis are thus essentially extratectal. Responses to eye illumination were abolished by contralateral pretectum-ablation but normal after the corresponding lesion on the ipsilateral side. Contralateral pretectum thus plays an important role for dorsal light response and negative phototaxis. To determine the roles of pretectal efferent pathways for the responses, animals with a midmesencephalichemisection were tested. Noncrossed pretecto-reticular fibers from the ipsilateral pretectum and crossed fibers from the contralateral side were transected. Eye illumination on the lesioned side evoked negative phototaxis but no dorsal light response. Eye illumination on the intact side evoked an enhanced dorsal light response, whereas negative phototaxis was replaced with straight locomotion or positive phototaxis. The crossed pretecto-reticular projection is thus most important for the dorsal light response, whereas the noncrossed projection presumably plays the major role for negative phototaxis. Transection of the ventral rhombencephalic commissure enhanced dorsal light response; negative phototaxis was retained with smaller turning angles than normal. Spontaneous locomotion showed episodes of backward swimming and deficient roll control (tilting tendency). Transections of different spinal pathways were performed immediately caudal to the brain stem. All spinal lesions left dorsal light response in attached state unaffected; this response presumably is mediated by the brain stem. Spinal hemisection impaired all ipsiversive yaw turns; the animals spontaneously rolled to the intact side. Bilateral transection of the lateral columns impaired all yaw turns, whereas roll control and dorsal light response were normal. After transection of the medial spinal cord, yaw turns still could be performed whereas dorsal light response was suppressed or abolished, and a roll tilting tendency during spontaneous locomotion was seen. We conclude that the contralateral optic nerve projection to the pretectal region is necessary and sufficient for negative phototaxis and dorsal light response. The crossed descending pretectal projection is most important for dorsal light response, whereas the noncrossed one is most important for negative phototaxis. In the most rostral spinal cord, fibers for lateral yaw turns travel mainly in the lateral columns, whereas fibers for roll turns travel mainly in the medial spinal cord.

Factors Controlling the Change of Shape of Certain Nemertean and Turbellarian Worms

1958 ◽  
Vol 35 (4) ◽  
pp. 731-748 ◽  
Author(s):  
R. B. CLARK ◽  
J. B. COWEY
Keyword(s):  
Water Conservation ◽  
Ecological Factors ◽  
Longitudinal Axis ◽  
The Body ◽  
Cross Sectional ◽  
Ciliary Action ◽  
Theoretical Predictions ◽  
Observed Behaviour ◽  
Body Wall Musculature ◽  
Sectional Shape

1. Nemerteans and turbellarians have an inextensible fibre system around them in the form of a lattice of left- and right-handed spirals. The effect of this system on the change of shape on these worms has been analysed theoretically and compared with the observed behaviour of nine species of turbellarian and nemertean from widely differing habitats. 2. The following theoretical relationships have been studied: (a) Variation of the angle between the geodesics and the longitudinal axis of the worm during changes in length, and the role of the fibre system in limiting changes in length of the animal. (b) The change in cross-sectional shape during changes in length. (c) The extension of the fibres and the extensibility of the worms, assuming the fibres of the lattice to be elastic. 3. The species investigated conform with the theoretical predictions to varying degrees and have been grouped accordingly: (a) Geonemertes dendyi and Rhynchodemus bilineatus have low extensibilities and fit the prediction well. They are nearly circular in cross-section at all lengths as a result of their low extensibility and this is related to their terrestrial habit and need for water conservation. (b) Amphiporus lactifloreus, Lineus gesserensis and L. longissimus are moderately flattened in the relaxed position and have extensibilities between 6 and 10. They are marine crawling forms using cilia for locomotion and so must present a fairly large ciliated surface to the substratum. The fibre system does not limit contraction; the compression of the epithelial cells causes the observed extensibilities to fall a little short of the theoretical values. (c) Cerebratulus lacteus, Malacobdella grossa, Polycelis nigra and Dendrocoelum lacteum are very flattened forms and have very high theoretical extensibilities, but very low observed ones. The factors causing this are the thickness of the body-wall musculature (Cerebratulus), the limiting effect of longitudinal and circular reticulin fibres in the muscle layers, and the presence of dorso-ventral and diagonal muscles. Their flattened form is correlated with ecological factors (with swimming in Cerebratulus, with its parasitic life in the mantle of bivalves in Melacobdella) or with physical ones in turbellarians where a permanently flattened form is necessary for these worms to move by ciliary action.

Coordinated righting behaviour in locusts

2001 ◽  
Vol 204 (4) ◽  
pp. 637-648 ◽  
Author(s):  
A.A. Faisal ◽  
T. Matheson
Keyword(s):  
Driving Force ◽  
Flat Surface ◽  
Longitudinal Axis ◽  
Upright Position ◽  
The Body ◽  
The Other ◽  
Legged Robots ◽  
Naturally Occurring ◽  
Key Features ◽  
Low Levels

A locust placed upside down on a flat surface uses a predictable sequence of leg movements to right itself. To analyse this behaviour, we made use of a naturally occurring state of quiescence (thanatosis) to position locusts in a standardised upside-down position from which they spontaneously right themselves. Locusts grasped around the pronotum enter a state of thanatosis during which the limbs can be manipulated into particular postures, where they remain, and the animal can be placed upside down on the ground. When released, thanatosis lasts 4–456 s (mean 73 s) before the animal suddenly becomes active again and rights itself within a further 600 ms. Thanatosis is characterised by very low levels of leg motor activity. During righting, one hind leg provides most of the downward force against the ground that rolls the body around a longitudinal axis towards the other side. The driving force is produced by femoral levation (relative to the body) at the trochanter and by tibial extension. As the animal rolls over, the hind leg on the other side is also levated at the trochanter, so that it does not obstruct the movement. The forelegs and middle legs are not required for successful righting but they can help initially to tip the locust to one side, and at the end of the movement they help stop the roll as the animal turns upright. Individual locusts have a preferred righting direction but can, nevertheless, roll to either side. Locusts falling upside down through the air use both passive and active mechanisms to right themselves before they land. Without active movements, falling locusts tend to rotate into an upright position, but most locusts extend their hind leg tibiae and/or spread their wings, which increases the success of mid-air righting from 28 to 49 % when falling from 30 cm. The rapid and reliable righting behaviour of locusts reduces the time spent in a vulnerable upside-down position. Their narrow body geometry, large hind legs, which can generate substantial dorsally directed force, and the particular patterns of coordinated movements of the legs on both sides of the body are the key features that permit locusts to right themselves effectively. The reliability of autonomous multi-legged robots may be enhanced by incorporating these features into their design.

Potential and Viscous Parts of the Thrust Deduction and Wake Fraction for an Ellipsoid of Revolution

1960 ◽  
Vol 4 (03) ◽  
pp. 1-16
Author(s):  
Stavros Tsakonas ◽  
Winnifred R. Jacobs
Keyword(s):  
Boundary Layer ◽  
Potential Flow ◽  
Functional Dependence ◽  
Longitudinal Axis ◽  
Layer Growth ◽  
The Body ◽  
Displacement Thickness ◽  
Layer Effect ◽  
Ellipsoid Of Revolution ◽  
Equivalent Sources

Expressions are developed for wake fraction and thrust deduction due to the potential flow and to the boundary-layer effects for a fully-submerged prolate ellipsoid of revolution. The functional dependence of wake fraction and thrust deduction on axial-propeller clearance, body slenderness, after body geometry, and Reynolds number (scale effect) are exhibited for both potential and viscous-flow cases. Closed-form expressions are derived for the potential-flow case by representing the body by a line source-sink distribution and the propeller action by a sink disk. The boundary-layer effect is determined by Lighthill's method of equivalent sources distributed on the surface having strength proportional to the displacement thickness and its derivative. The wake is replaced by a cylinder of diameter equal to twice the displacement thickness at the stern. Although in practice the propeller is usually fully submerged in the wake of the hull, in this case the substitute cylinder has been shown by computation to be no wider than the hub diameter and thus the propeller is operating in a potential field. This consideration is fundamental to the construction of a possible mathematical model having the surface sources mentioned and an equivalent sink on the longitudinal axis whose position is determined on the basis of the velocity distribution in the wake. Computational work is carried out for a modification of the airship Akron. Four different methods, with various degrees of accuracy, are used for the evaluation of the boundary-layer growth in order to ascertain the degree of sensitivity of the thrust deduction and wake fraction to the boundary-layer development.

scholarly journals Morphometry of the mandibular foramen applied to the local anesthetic block to inferior alveolar nerve in boars (Sus scrofa scrofa Linnaeus, 1758)

2020 ◽  
Vol 57 (1) ◽  
pp. e161658
Author(s):  
Caroline Bures de Paulo ◽  
Henrique Inhauser Riceti Magalhães ◽  
Ygor Henrique De Paula ◽  
Jeferson Borges Barcelos ◽  
Fabiano Braz Romão ◽  
...  
Keyword(s):  
Sus Scrofa ◽  
Inferior Alveolar Nerve ◽  
Longitudinal Axis ◽  
The Body ◽  
Lateral Margin ◽  
Ventral Margin ◽  
Mandibular Foramen ◽  
Condylar Process ◽  
Therapeutic Procedures ◽  
Commercial Farms

Boars kept on commercial farms use their canine teeth as a mechanism of defense and attack in order to express their natural instincts, which could result in fractures of the teeth and jaws. Thus, utilizing local desensitization of the inferior alveolar nerve is crucial for executing therapeutic procedures in the oral cavities of those animals. Then, the goal is to carry out the morphometry of the mandibular foramen of that species, correlating it with the mandibular structures, while doing so in the safest manner for the animals. For that purpose, six hemimandibles of young-aged Sus scrofa scrofa were used, from which the proposed measurements were taken. On average, the lateral margin of the condylar process stood 142.43 mm away from the root of the lower medial incisive tooth. The longitudinal axis of the body of the mandible measured 22.3 mm at the level of the diastema that exists between the fourth lower premolar tooth and the first lower molar tooth. The mandibular foramen, from the caudal limit of the ventral margin, would be positioned at26.6 mm from the ventral margin of the angle of the mandible in that level, 34.92 mm away from the medial margin of the condylar process, and 38.63 mm away from the dorsal limit from the caudal margin of the coronoid process. The lack of statistically significant differences, and observing that the osseous accident under scrutiny had been positioned in the ramus of the mandible, indicated that the proposed procedure should be performed from the introduction of the needle in an oblique and rostrodorsal direction for 2.0 cm, and angulated at 60º with the anatomic reference created by the medial demarcation obtained via the support of the thumb on the lateral margin of the ramus of the mandible, ventrally to the zygomatic arch, all while preserving neighboring structures and establishing an unheard-of anesthetic methodology for boars.

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