Lateral Body Research Articles

Sensation of Anteroposterior and Lateral Body Tilt Induced by Electrical Stimulation of Ankle Tendons

While virtual reality technology enables users to walk on surfaces of various shapes in virtual environments, these experiences are often on a flat floor, and any discordance between visual and somatosensory information hampers the immersive experience. To resolve this issue, we have focused on the ankle joint angle as an essential cue in detecting the surface shape of the ground. To modulate the sensation of the ankle joint angle, we propose novel percutaneous electrical stimulation methods that stimulate four targeted ankle tendons: the tibialis anterior muscle tendon, the Achilles tendon, the peroneus longus muscle tendon, and the flexor digitorum longus tendon. Since electrically stimulating the elbow tendon is known to evoke reflexive hand movement, electrically stimulating the ankle tendon is expected to evoke a body tilt due to illusory changes in the ankle joint angle. In this study, we designed electrode configurations to stimulate the above four ankle tendons using a finite element analysis and investigated the effect of electrically stimulating the ankle tendons on the subjective sensation of body tilt and actual body sway through psychophysical experiments. The results revealed that applying this stimulation with our novel electrode configurations can induce a subjective sensation of body tilt and actual body sway in a direction opposite to the stimulated part.

Querying the significance of patient position during computerized tomography on the reliability of pre-percutaneous nephrolithotomy planning.

Computerized tomography (CT) is considered indispensable in percutaneous nephrolithotomy (PCNL) planning. We aimed to define the reliability of pre-PCNL CT for planning renal access by assessing renal positional changes between supine and prone CTs. CT urographies (CTU) of 30 consecutive patients were reviewed for distances upper pole (UP)-diaphragm, UP-diaphragm attachment, renal pelvis (RP)-lateral body wall, RP- posterior body wall, and lower pole (LP)- anterior-superior iliac spine (ASIS). The posterior and lateral renal axes angles were also calculated. The most consistent overall movement in transition from prone to supine was backward rotation, as demonstrated by a decrease in distance UP-posterior body wall (p = 0.010) and increase in the posterior renal angle (p < 0.0001). This finding correlated with the patient's body mass index (BMI) (p = 0.029). The left kidney was more mobile than the right one, moving significantly for five of the measured parameters compared to the right kidney which moved significantly for only two parameters. The UP-diaphragm distance of the left kidney correlated with age (p = 0.014), the RP-lateral wall distance correlated with previous abdominal surgery (p = 0.006), and the RP-posterior wall distance with BMI (p = 0.017). On the right, the UP-diaphragm distance correlated with gender (p = 0.002) and the lateral renal rotation was smaller (p = 0.046). Kidneys present significant mobility between supine and prone positions. CT assessment should be performed in the position expected during surgery and should be interpreted with caution, while a real-time imaging modality should be used in the operating room.

Proprioceptive feedback design for gait synchronization in collective undulatory robots

The collective movement of animals has long been a source of inspiration for multi-agent swarm robotics. One of the fundamental goals for swarm robotics study is to understand how effective and robust collective behaviors can emerge from simple interaction principles. When animal or robot collectives are in high-density configurations the ability for visual or auditory sensing is diminished and the opportunities for interacting through mechanical contact are enhanced. In this paper, we study how robots that move through lateral body undulation in close proximity are capable of synchronizing their oscillatory gaits through contact interactions between adjacent robots. Critically, gait phase synchronization occurs without the requirement for robot–robot communication, and instead can be engineered as an emergent property of the robot control system. We present a proprioceptive feedback control system that generates collective gait phase synchronization of undulatory robots in experiment and simulation. We first validate this control system using a simple one-dimensional toy model to demonstrate how proprioceptive feedback governs phase synchronization. Simulations and experiments with undulatory three-link robots further demonstrate how phase synchronization can be controlled. Lastly, we demonstrate that robot pairs moving in a confined tunnel can synchronize their movements which leads to faster group locomotion through confined spaces.

An Anatomical Method for Rib Disconnection During Posterior Costotransversectomy for Paravertebral Access to the Ventral Thoracic Spine

Posterior costotransversectomy in the thoracic spine is commonly used for degenerative diseases, tumors, trauma, and other operative indications. It involves resection of the rib head after the ligamentous complexes have been disconnected from the transverse process and lateral vertebral body. The current literature provides only vague descriptions of the steps involved in rib disconnection with respect to posterior costotransversectomy. Through cadaveric studies and in vivo application, a stepwise method for rib disconnection is described. This manuscript is the first to outline an anatomical method for rib disconnection during costotransversectomy.

Morphology of immatures of the thelytokous ant, Monomorium triviale Wheeler (Formicidae: Myrmicinae: Solenopsidini) with descriptions of the extraordinary last-instar queen larvae

The ant genus Monomorium is one of the most species-rich but taxonomically problematic groups in the hyperdiverse subfamily Myrmicinae. An East Asian species, M. triviale Wheeler, produces both reproductive queens and sterile workers via obligate thelytokous parthenogenesis. Here, we describe the immature forms of M. triviale based on light and scanning electron microscopy observations, with a note on the striking caste dimorphism in the last larval instar. The last-instar queen larvae were easily recognized by their large size, aphaenogastroid body shape, and rows of doorknob-like tubercles on the lateral and dorsal body surface. This type of queen-specific structure has not been found in ants in general, let alone congeneric species found in Japan. In stark contrast to the queen larvae, worker larvae showed a pheidoloid body shape and a body surface similar to other ants. The worker larvae were estimated to have three instars, consistent with previously described congeners. The pupae of both castes had no cocoon, a characteristic commonly described in other Myrmicinae species. In total, the developmental period from egg to adult worker averaged 59 days under 25C. We discuss possible functions of the tubercles of queen larvae based on previous studies.

Rigid ureteroscopic lithotripsy in the lateral decubitus position for upper urinary tract stones

BackgroundThe current study aimed to assess a novel ureteroscopic technique developed for treating upper urinary calculi based on a specially designed lateral decubitus body position that could avoid stone loss by adjusting to the effects of gravity.MethodsThis retrospective study examined patients with upper urinary calculi who were surgically treated from November 2008 to January 2020, using a new body position and a rigid ureteroscope. Clinical outcomes, stone-free rates, operative times and complications were evaluated, and factors that could influence treatment success were determined.ResultsIn total, 1080 patients were included, and 1145 operations were performed. The maximum calculus diameters were 11.22 ± 5.01 mm. Operative times were 48.60 ± 27.44 min. A total of 1042 cases were successfully treated, with a stone-free rate of 91.00%. Multivariate analysis showed that female sex (OR = 2.135, 95% CI 1.332–3.422, P = 0.002), thin scope standby (OR = 1.643, 95% CI 1.074–2.514, P = 0.022), laser lithotripsy (OR = 5.087, 95% CI 2.400–10.785, P = 0.000) and stone size (OR = 0.946, 95% CI 0.912–0.981, P = 0.003) were independently associated with stone-free outcomes. In total, 2 ureteral perforations, 2 ureteric avulsions and 4 urosepsis cases were observed, but were all cured without sequelae.ConclusionsUreteroscopic lithotripsy in the lateral decubitus position is a safe and effective technique for treating upper urinary tract calculi, especially upper ureteral calculi.

Phenotypic response of male and neomale of O. mykiss parr subjected to 8º and 16 ºC water temperature during early life stage

Water temperature is an important modulator of variation of phenotype in poikilothermic fish and therefore of body shape. The present study explores the phenotypic response of commercial O. mykiss parr when they are subjected to rearing temperatures of 8º and 16ºC under controlled conditions with the aim of demonstrating, with the use of Landmark-Based Geometric Morphometrics, the influence of rearing temperature on body shape. O. mykiss males and neomales from eggs to parr stages, belonging to the same family and strain, were reared at different temperatures (8ºC and 16ºC) and grouped according to: Group 16ºC/neomales (n = 15), Group 16ºC/males (n = 15), Group 8ºC/neomales (n = 15) and Group 8ºC/males (n = 15). Differences in body shape among sex and rearing temperatures were examined by geometric morphometrics and traditional morphometry. At 16 weeks, geometric morphometric analysis revealed a dimorphism, which was not detected by traditional morphometry, mainly in the dorsal and caudal fin area. This dimorphism was not observed in neomales. This difference may be the product of the potential for phenotypic plasticity and adaptation to genetically controlled environmental and local fluctuations, which affects to indicators of adaptation in unfavorable environmental conditions such a biomechanical action of swimming and propulsion. In conclusion, this study demonstrates the differential effect of 8º and 16ºC water temperature on lateral body shape in male O. mykiss parr during the early stages of body development and in controlled conditions.

Estimation of body weight in captive Amur tigers (Panthera tigris altaica).

So far, there has been no safe and convenient method to weigh the large fierce animals, like Amur tigers. To address this problem, we built models to predict the body weight of Amur tigers based on the fact that body weight is proportional to body measurements or age. Using the method of body measurements, we extracted the body measurements from 4 different kinds of the lateral body image of tigers, that is, total lateral image, central lateral image, ellipse fitting image, and rectangle fitting image, and then we respectively used artificial neural network (ANN) and power regression model to analyze the predictive relationships between body weight and body measurements. Our results demonstrated that, among all ANN models, the model built with rectangle fitting image had the smallest mean square error. Comparatively, we screened power regression models which had the smallest Akakai information criteria (AIC). In addition, using the method of age, we fitted nonlinear regression models for the relationship between body weight and age and found that, for male tigers, logistic model had the smallest AIC. For female tigers, Gompertz model had the smallest AIC. Consequently, this study could be applied to estimate body weight of captive, or even wild, Amur tigers safely and conveniently, helping to monitor individual health and growth of the Amur tiger populations.

Total, longitudinal and transverse body sizes in men with psoriasis of different somatotypes

Using a constitutional approach to predict the onset of a disease can be key not only to solving the problem of late-stage lifestyle modification therapy but also to understanding the deep, seemingly incomprehensible links between organs and body structure. The aim of the study was to establish and analyze the differences in total, longitudinal and transverse body sizes between healthy and/or psoriatic men of different somatotypes depending on the severity of the disease. Anthropo-somatotypological examination was performed on Ukrainian men (aged 22 to 35 years) with psoriasis (n=100, including 32 with mild and 68 with severe). A clinical assessment of the severity and area of psoriatic lesions was performed using the PASI index. Anthropometric data of 82 practically healthy men of the same age group was taken from the data bank of the research center of National Pirogov Memorial Medical University, Vinnytsya. Statistical processing of the obtained results was performed in the license package “Statistica 5.5” using non-parametric evaluation methods. In patients with mild and severe psoriasis, men of mesomorphic and endo-mesomorphic somatotypes in comparison with healthy men of the corresponding somatotypes, higher values of almost all total (in the endo-mesomorphs with severe disease), transverse (except for shoulder width) and lateral body size (except endo-mesomorphs with severe disease) was found. In patients with psoriasis, men of endo-mesomorphic somatotype with a mild course of the disease found greater than in patients with a similar course men of mesomorphic somatotype, body weight, length and surface area, height of acromial and finger anthropometric points, and transverse middle thoracic diameters and anteroposterior middle thoracic diameter; and in patients with psoriasis men of endo-mesomorphic somatotype with a severe course of the disease – only greater values than in patients with a similar course of the disease men of mesomorphic somatotype, interspinous distance. When comparing the total, longitudinal and transverse dimensions of the body between men with psoriasis of the corresponding somatotypes, in representatives of the mesomorphic somatotype with a mild course of the disease found greater than with severe course, body length values and lower – posterior middle thoracic diameter. The revealed differences in total, longitudinal and transverse body sizes between healthy and/or patients with mild or severe psoriasis Ukrainian men of mesomorphic and endo-mesomorphic somatotypes provide an opportunity to increase the effectiveness of the use of body structure and size to identify risk groups psoriasis.

CALCULATION OF THE HYDRODYNAMIC INTERACTION BETWEEN TWO ENCOUNTERING BODIES IN COUPLING MULTI-FREEDOM MOTIONS

ellipsoids are taken as an example. By coupling the motion equations of the two bodies and the fluid flow equations, the interaction forces and moments are calculated, and the tracks are predicted. The numerical results for the model fixed motion (only free to surge) at constant speed are compared with those published in literature for the validation of the method proposed in this paper, and good agreement is found. On this basis, more complicated multi-degree of freedom motions in surge, sway and yaw directions induced by the interaction effects are simulated. By systematically comparing and analyzing the numerical results obtained at different speeds, lateral distances and body sizes, the influences of speed and lateral distance and body size The sway and yaw motion will be induced additionally due to the interaction effects when two encountering bodies sail in close proximity, which may lead to the collision accident. In the present study, two on the hydrodynamic forces are elucidated.

Description of a New Scaled Species of Ptychostomella (Gastrotricha: Macrodasyida) from the Brazilian Coast and a Cladistics Analysis of the Genus

A new species of marine Gastrotricha from the north coast of São Paulo state, Brazil, is described. Adults of Ptychostomella sebastiana sp. nov. are unique in that they possess a pair of dorsolateral “rod-like” cephalic sensory organs and subrectangular scales covering the lateral body surfaces. A cladistic analysis was performed to investigate the internal relationship of the representatives of the taxa based on morphological data. Our analysis supported the monophyly of the taxon Ptychostomella, but its internal phylogenetic relationships are not well established due to the low phylogenetic signal of morphological characters used in the present study.

Molecular phylogenetic analysis of the genus Gloydius (Squamata, Viperidae, Crotalinae), with description of two new alpine species from Qinghai-Tibet Plateau, China.

We provide a molecular phylogeny of Asian pit vipers (the genus Gloydius) based on four mitochondrial genes (12S, 16S, ND4, and cytb). Sequences of Gloydiushimalayanus, the only member of the genus that occurs south of the Himalayan range, are included for the first time. In addition, two new species of the genus Gloydius are described based on specimens collected from Zayu, Tibet, west of the Nujiang River and Heishui, Sichuan, east of the Qinghai-Tibet Plateau. The new species, Gloydiuslipipengi sp. nov., can be differentiated from its congeners by the combination of the following characters: the third supralabial not reaching the orbit (separated from it by a suborbital scale); wide, black-bordered greyish postorbital stripe extending from the posterior margin of the orbit (not separated by the postoculars, covering most of the anterior temporal scale) to the ventral surface of the neck; irregular black annular crossbands on the mid-body; 23-21-15 dorsal scales; 165 ventral scales, and 46 subcaudal scales. Gloydiusswildsp. nov. can be differentiated from its congeners by the narrower postorbital stripe (only half the width of the anterior temporal scale, the lower edge is approximately straight and bordered with white); a pair of arched stripes on the occiput; lateral body lakes black spots; a pair of round spots on the parietal scales; 21 rows of mid-body dorsal scales; zigzag dark brown stripes on the dorsum; 168–170 ventral scales, and 43–46 subcaudal scales. The molecular phylogeny in this study supports the sister relationship between G.lipipengisp. nov. and G.rubromaculatus, another recently described species from the Qinghai-Tibet Plateau, more than 500 km away, and indicate the basal position of G.himalayanus within the genus and relatively distant relationship to its congeners.

Clinical oberservation on rotator cuff suture threader and strapping suture in meniscus tear under arthroscopy

To explore clinical effect of arthroscopic meniscus tear strapping suture by rotator cuff suture threader. Forty patients with meniscus tear injury admitted from July 2015 to May 2019, including 27 males and 13 females, aged from 20 to 55 years old with an average of (36.0±1.4) years old. Menisci laceration was sutured with rotator cuff suture thread under arthroscopy. Postoperative complication was observed, Lysholm knee joint score before and after operation at 12 months were used to evaluate clinical effects, visual analogue scale (VAS) and range of knee flexion and extension were applied to evaluate recovery of pain and function. All patients were followed up from 12 to 15 months with an average of (12.6±0.7) months.No complication such as joint effusion, suture failure occurred. Two patients occurred mild pain after activity without clinical physical abnormality, and 1 patient manifested moderate pain with joint space tenderness, the other rest without abnormal. Lysholm knee joint score was increased from (49.55±1.21) preoperatively to (98.95±0.42) at 12 months after operation, VAS score decreased from (5.18±0.78)preoperatively to (1.03±0.77) at 12 months after operation, and range of knee joint flexion and extension activity increased from (50.63±9.20)°preoperatively to (130.38±4.99)°after operation, and there were statistical differences in Lysholm knee joint score, VAS and range of knee joint flexion and extension activity (P< 0.05). Arthroscopic strapping suture by rotator cuff suture threading device applies to most meniscus injuries, including medial meniscus posterior horn tears, lateral meniscus body tears and lateral meniscus posterior horn tears. This technique meets the need of full-internal meniscus suture without specialmeniscus suture, and has advantages of convenient operation, less complications and good postoperative function.

Ecological and biological traits of non-native freshwater fish species differentiate them from native species in China

China’s freshwater ecosystems are gradually invaded by an increasing number of non-native fish species. However, to date, some controversy about the number of native and non-native freshwater fish species in wild habitats and very limited information on ecological or biological traits mediating fish introduction success at a national scale have prevented the proposal and implementation of targeted conservation and management strategies. To address these urgent issues, first we compiled an up-to-date inventory of 1,797 fish species (1,597, 84, and 116 native, exotic (originating from outside China), and translocated (originating from within China) species, respectively) along with 13 traits encompassing various ecological and life-history strategies for each species, which is the most comprehensive freshwater fish database in China as we know. Here, we found that non-native species mainly belonged to three orders (Perciformes, Siluriformes, and Cypriniformes) and three families (Cichlidae, Cyprinidae, and Salmonidae). Native species were significantly (P < 0.001) different from both exotic and translocated species according to their quantitative traits, while no remarkable differences between exotic and translocated species were detected (P = 0.93). Specifically, G-tests of independence, Similarity Percentage Analysis (SIMPER), and Mann-Whitney-Wilcoxon rank sum tests showed that compared to native species, species with relatively higher vulnerability (intrinsic vulnerability of fishes to fishing), trophic level, and pectoral fin vertical position, but less resilience and lateral body shape were deemed as potential candidates for introduction and dispersal in China.

Predicting the histological invasiveness of pulmonary adenocarcinoma manifesting as persistent pure ground-glass nodules by ultra-high-resolution CT target scanning in the lateral or oblique body position.

Ultra-high-resolution computed tomography (U-HRCT) has improved image quality for displaying the detailed characteristics of disease states and lung anatomy. The purpose of this study was to retrospectively examine whether U-HRCT target scanning in the lateral or oblique body position (protocol G scan) could predict histological invasiveness of pulmonary adenocarcinoma manifesting as pure ground-glass nodules (pGGNs). From January 2015 to December 2016, 260 patients with 306 pathologically confirmed pGGNs who underwent preoperative protocol G scans were retrospectively reviewed and analyzed. The U-HRCT findings of preinvasive lesions [atypical adenomatous hyperplasias (AAH) and adenocarcinomas in situ (AIS)] and invasive pulmonary adenocarcinomas [minimally invasive adenocarcinomas (MIA) and invasive adenocarcinomas (IAC)] were manually compared and analyzed using orthogonal multiplanar reformation (MPR) images. The logistic regression model was established to determine variables that could predict the invasiveness of pGGNs. Receiver operating characteristic (ROC) curve analysis was performed to evaluate their diagnostic performance. There were 213 preinvasive lesions (59 AAHs and 154 AISs) and 93 invasive pulmonary adenocarcinomas (53 MIAs and 40 IACs). Compared with the preinvasive lesions, invasive adenocarcinomas exhibited a larger diameter (13.5 vs. 9.3 mm, P=0.000), higher mean attenuation (-571 vs. -613 HU, P=0.002), higher representative attenuation (-475 vs. -547 HU, P=0.000), lower relative attenuation (-339 vs. -292 HU, P=0.000) and greater frequencies of heterogeneity (P=0.001), air bronchogram (P=0.000), bubble lucency (P=0.000), and pleural indentation (P=0.000). Multiple logistic analysis revealed that larger diameter [odds ratio (OR), 1.328; 95% CI: 1.208-1.461; P=0.000] and higher representative attenuation (OR, 1.005; 95% CI: 1.003-1.007; P=0.000) were significant predictive factors of invasive pulmonary adenocarcinomas from preinvasive lesions. The optimal cut-off value of the maximum diameter for invasive pulmonary adenocarcinomas was larger than 10 mm (sensitivity, 66.7%; specificity, 72.8%). The imaging features based on protocol G scanning can effectively help predict the histological invasiveness of pGGNs. The maximum diameter and representative attenuation are important parameters for predicting invasiveness.

A left lateral body position increases pulmonary vein stress in healthy humans.

Pulmonary vein (PV) stretch is proarrhythmic for atrial fibrillation (AF). AF patients often report that a left lateral (LL) body position can trigger arrhythmia symptoms. Because the PV myocardium is thought to trigger AF, we hypothesized that the LL compared to the supine body position increases PV wall stress. Functional cardiac magnetic resonance imaging was performed in supine and LL recumbent body position in awake condition in healthy human volunteers (n = 20). Following a change from supine to LL position, the heart moved in an anterior‐LL direction in the thorax. The right superior PV diameter was increased by 19% (24.6 ± 3.1 vs. 20.7 ± 3.2 mm, p = 0.009) and left atrial (LA) volume was larger by 17% (61.7[15.4] vs. 51.0[17.8] ml, p = 0.015) in LL than supine position, respectively. The passive LA conduit fraction (normalized difference between maximum and pre‐contraction LA volume) increased by 25% in LL compared to supine position (19.6 ± 9.0 vs. 15.7 ± 7.6%, respectively, p = 0.016). Local wall stress in the PV regions increased in LL compared to supine position (overall mean: 1.01 ± 0.12 vs. 1.10 ± 0.10 arb. unit, LL vs. supine, position effect p = 0.041), whereas this was not the case in the LA walls (overall mean: 1.18 ± 0.31 vs. 1.21 ± 0.21 arb. unit, LL vs. supine, position effect p = 0.381). In conclusion, a left lateral body position increases PV myocardial stress during the atrial relaxation phase of healthy volunteers. These results have implications for the mechanisms of posture‐triggered AF.

Body Caudal Undulation Measured by Soft Sensors and Emulated by Soft Artificial Muscles.

We propose the use of bio-inspired robotics equipped with soft sensor technologies to gain a better understanding of the mechanics and control of animal movement. Soft robotic systems can be used to generate new hypotheses and uncover fundamental principles underlying animal locomotion and sensory capabilities, which could subsequently be validated using living organisms. Physical models increasingly include lateral body movements, notably back and tail bending, which are necessary for horizontal plane undulation in model systems ranging from fish to amphibians and reptiles. We present a comparative study of the use of physical modeling in conjunction with soft robotics and integrated soft and hyperelastic sensors to monitor local pressures, enabling local feedback control, and discuss issues related to understanding the mechanics and control of undulatory locomotion. A parallel approach combining live animal data with biorobotic physical modeling promises to be beneficial for gaining a better understanding of systems in motion.

Histologic Examination of a Sea Pig (Scotoplanes sp.) Using Bright Field Light Microscopy

Sea pigs (Scotoplanes spp.) are deep-sea dwelling sea cucumbers of the phylum Echinodermata, class Holothuroidea, and order Elasipodida. Few reports are available on the microscopic anatomy of these deep-sea animals. This study describes the histologic findings of two, wild, male and female Scotoplanes sp. collected from Monterey Bay, California. Microscopic findings were similar to other holothuroids, with a few notable exceptions. Sea pigs were bilaterally symmetrical with six pairs of greatly enlarged tube feet arising from the lateral body wall and oriented ventrally for walking. Neither a rete mirabile nor respiratory tree was identified, and the large tube feet may function in respiration. Dorsal papillae protrude from the bivium and are histologically similar to tube feet with a large, muscular water vascular canal in the center. There were 10 buccal tentacles, the epidermis of which was highly folded. Only a single gonad was present in each animal; both male and female had histologic evidence of active gametogenesis. In the male, a presumed protozoal cyst was identified in the aboral intestinal mucosa, and was histologically similar to previous reports of coccidians. This work provides control histology for future investigations of sea pigs and related animals using bright field microscopy.

Spontaneous Gait Transitions of Sprawling Quadruped Locomotion by Sensory-Driven Body–Limb Coordination Mechanisms

Deciphering how quadrupeds coordinate their legs and other body parts, such as the trunk, head, and tail (i.e., body–limb coordination), can provide informative insights to improve legged robot mobility. In this study, we focused on sprawling locomotion of the salamander and aimed to understand the body–limb coordination mechanisms through mathematical modeling and simulations. The salamander is an amphibian that moves on the ground by coordinating the four legs with lateral body bending. It uses standing and traveling waves of lateral bending that depend on the velocity and stepping gait. However, the body–limb coordination mechanisms responsible for this flexible gait transition remain elusive. This paper presents a central-pattern-generator-based model to reproduce spontaneous gait transitions, including changes in bending patterns. The proposed model implements four feedback rules (feedback from limb-to-limb, limb-to-body, body-to-limb, and body-to-body) without assuming any inter-oscillator coupling. The interplay of the feedback rules establishes a self-organized body–limb coordination that enables the reproduction of the speed-dependent gait transitions of salamanders, as well as various gait patterns observed in sprawling quadruped animals. This suggests that sensory feedback plays an essential role in flexible body–limb coordination during sprawling quadruped locomotion.

B-PO03-143 LOCALIZED PULMONARY VEIN STRESS INDUCED BY POSTURAL CHANGE IN HEALTHY HUMANS

A change in body position can trigger cardiac arrhythmias. Increased stress of atrial myocardium is proarrhythmic. The effect of body position on localized atrial stress and strain is unknown. We sought to evaluate the effect of body position on localized stress and strain in the left atrium (LA) and pulmonary veins (PV). Functional cardiac magnetic resonance imaging was carried out in supine and left lateral (LL) body position in healthy human volunteers (n=20) that resembled patients with atrial fibrillation in terms of sex, age and BMI. We analyzed local LA strain with a feature-tracking algorithm. Following a change from supine to LL position, the heart moved in an anterior-LL direction in the thorax. Maximal LA volume was 17% larger in LL than supine position (61.7±15.4 (mean±SD) vs. 51.0 (17.8) (median (IQR)) ml, respectively, p=0.015). The diameter of the right superior pulmonary vein (RSPV) was larger in LL than in supine position (24.6±3.9 mm vs. 20.7±4.4mm, respectively, p=0.003). Two-dimensional (2D) strain during the cardiac cycle (defined as the vector summation of radial motion fraction and longitudinal strain) was lower in the RSPV posterior wall and higher in the right inferior PV posterior wall in LL than supine position (16.8±5.4 vs. 21.1±9.6 arbitrary unit (AU), p=0.048, and 19.7±7.9 vs. 14.6±6.9AU, p=0.023, LL vs. supine, respectively). Maximal longitudinal strain was lower in the LA posterior wall in LL compared to supine (43.4±22.5 vs. 49.1±32.5%, LL vs. supine, p=0.025). In contrast, the atrial septum deformed more in LL than in supine position (2D strain: 66.8±18.2 vs. 57.0±16.5AU, respectively, p=0.030). Body position change induced localized alterations in LA and PV stress and strain. These results imply that posture-triggered atrial arrhythmias may be caused by altered strain.