Comparison of spatiotemporal and angular parameters during shallow water walking in different immersion depths by older adults with and without Parkinson's disease.

BACKGROUND: People with Parkinson's Disease (PwPD) have motor symptoms that directly interfere on dry land walking performance. Despite the shallow water walking is a viable and beneficial physical intervention for PwPD, it lacks information on the comparison of the biomechanical responses of the shallow water walking by PwPD and age paired healthy individuals. RESEARCH QUESTION: Are there differences in the spatiotemporal and angular responses of shallow water walking by older adults with and without Parkinson's disease? METHODS: In this cross-sectional study, ten older adults (9 men/1 women) with Parkinson disease (PwPD group) and ten older adults (3 men/7 women) without Parkinson's disease (Older group) walked in shallow water at self-selected comfortable speed on pool floor in the immersion depths of waist and xiphoid levels. The 2D kinematic data from the sagittal plane was collected to calculate the walking speed, stride length, stride frequency, duty factor, walk ratio, lower limb joints' range of motion and peak angular speed RESULTS: Both groups reduced similarly the walking speed with the immersion depth increase. The speed decrease was achieved by a reducing both the stride frequency and stride length only in the PwPD. The PwPD had lower contact phase than Older in the waist depth, probably due to the reduced risk of fall in water immersion and to attenuate drag force effects. The total range of joint motion was similar between groups, while the peak angular speed of ankle and knee reduced in the deeper depth in both groups. SIGNIFICANCE: The present findings can help professionals of aquatic rehabilitation to choose the best depth for exercise programs, according to the treatment objectives. To our knowledge, this was the first study that analyzed spatiotemporal and angular variables during shallow water walking of PwPD at different depths and compared them with older people without Parkinson's disease.

Influence of Gestational Age on Pelvic Floor Muscle Activity, Plantar Contact, and Functional Mobility in High-Risk Pregnant Women: A Cross-Sectional Study.

During pregnancy, biomechanical changes are observed due to hormonal and physical modifications, which can lead to alterations in the curvature of the spine, balance, gait patterns, and functionality of the pelvic floor muscles. This study aimed to investigate the progressive impact of biomechanical changes that occur during gestational weeks on the myoelectric activity of the pelvic floor muscles, plantar contact area, and functional mobility of high-risk pregnant women. METHODS: This was a cross-sectional observational study carried out from November 2022 to March 2023. A total of 62 pregnant women of different gestational ages with high-risk pregnancies were analyzed using surface electromyography to assess the functionality of the pelvic floor muscles, plantigraphy (Staheli index and plantar contact area), and an accelerometer and gyroscope using the timed up and go test via an inertial sensor on a smartphone. Descriptive statistics and multivariate linear regression analyses were carried out to test the predictive value of the signature. RESULTS: Increasing weeks of gestation resulted in a decrease in the RMS value (ß = -0.306; t = -2.284; p = 0.026) according to the surface electromyography analyses. However, there was no association with plantar contact (F (4.50) = 0.697; p = 0.598; R2 = 0.53). With regard to functional mobility, increasing weeks of gestation resulted in a decrease in time to standing (ß = -0.613; t = -2.495; p = 0.016), time to go (ß = -0.513; t = -2.264; p = 0.028), and first gyrus peak (ß = -0.290; t = -2.168; p = 0.035). However, there was an increase in the time to come back (ß = 0.453; t = 2.321; p = 0.025) as the number of gestational weeks increased. CONCLUSIONS: Increased gestational age is associated with a reduction in pelvic floor myoelectric activity. The plantar contact area did not change over the weeks. Advancing gestation was accompanied by a decrease in time to standing, time to go, and first gyrus peak, as well as an increase in time to come back.

Historical Field Records Reveal Habitat as an Ecological Correlate of Locomotor Phenotypic Diversity in the Radiation of Neotropical Geophagini Fishes.

AbstractPhenotypic macroevolutionary studies provide insight into how ecological processes shape biodiversity. However, the complexity of phenotype-ecology relationships underscores the importance of also validating phenotype-based ecological inference with direct evidence of resource use. Unfortunately, macroevolutionary-scale ecological studies are often hindered by the challenges of acquiring taxonomically and spatially representative ecological data for large and widely distributed clades. The South American cichlid fish tribe Geophagini represents a continentally distributed radiation whose early locomotor morphological divergence suggests habitat as one ecological correlate of diversification, but an association between locomotor traits and habitat preference has not been corroborated. Field notes accumulated over decades of collecting across South America provide firsthand environmental records that can be mined for habitat data in support of macroevolutionary ecological research. In this study, we applied a newly developed method to transform descriptive field note information into quantitative habitat data and used it to assess habitat preference and its relationship to locomotor morphology in Geophagini. Field note-derived data shed light on geophagine habitat use patterns and reinforced habitat as an ecological correlate of locomotor morphological diversity. Our work emphasizes the rich data potential of museum collections, including often-overlooked material such as field notes, for evolutionary and ecological research.

Visual-Aided Obstacle Climbing by Modular Snake Robot.

Snake robots, also known as apodal robots, are among the most common and versatile modular robots. Primarily due to their ability to move in different patterns, they can evolve in scenarios with several constraints, some of them hardly accessible to other robot configurations. This paper deals with a specific environment constraint where the robot needs to climb a prismatic obstacle, similar to a step. The objective is to carry out simulations of this function, before implementing it in the physical model. To this end, we propose two different algorithms, parameterized by the obstacle dimensions determined by image processing, and both are evaluated in simulated experiments. The results show that both algorithms are viable for testing in real robots, although more complex scenarios still need to be further studied.

The sublethal impacts of five insecticidal formulations on Oryzaephilus surinamensis behavioral traits.

BACKGROUND: Mortality caused by various pyrethroids, and neonicotinoids has been studied for stored-product insects in the past, yet limited information exists on the sublethal effects they can induce to Oryzaephilus surinamensis. In the current study, the sublethal effects of deltamethrin, λ-cyhalothrin, α-cypermethrin, etofenprox, and the mixture of acetamiprid with d-tetramethrin and piperonyl butoxide on the mobility of O. surinamensis in the presence or the absence of a food source was investigated. RESULTS: Lethal concentrations (LCs) were lower for deltamethrin, α-cypermethrin, and λ-cyhalothrin (LC10 = 0.000233, 0.000211, and 0.000271 mg active ingredient (a.i.) cm-2, LC30 = 0.000413, 0.000398, and 0.000447 mg a.i. cm-2, respectively), followed by etofenprox, and the mixture of acetamiprid with d-tetramethrin and piperonyl butoxide (LC10 = 0.00228 and 0.003267 mg a.i. cm-2, LC30 = 0.00437 and 0.01188 mg a.i. cm-2, respectively). Deltamethrin and λ-cyhalothrin negatively impacted adult walking behavior, increasing stop durations compared to controls. Adults exposed to LC10 and LC30 of λ-cyhalothrin, and LC30 of deltamethrin exhibited prolonged periods on their backs compared to the remaining treatments and the controls. The α-cypermethrin LC30-exposed adults exhibited significantly shorter walking and stopping durations than controls but demonstrated prolonged climbing on the arena walls compared to adults exposed to the remaining a.i. and the control. A similar trend was observed for etofenprox. CONCLUSIONS: Under sublethal concentrations, λ-cyhalothrin and deltamethrin increased stop intervals and reduced the duration of climbing attempts of O. surinamensis versus α-cypermethrin. These findings advance comprehension of the underexplored sublethal impacts of the tested a.i. on O. surinamensis adults, holding potential for leveraging insecticide-induced behavioral effects to enhance warehouse pest management. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Lysergic acid diethylamide induces behavioral changes in Caenorhabditis elegans.

Lysergic acid diethylamide (LSD) is a synthetic psychedelic compound with potential therapeutic value for psychiatric disorders. This study aims to establish Caenorhabditis elegans as an in vivo model for examining LSD's effects on locomotor behavior. Our results demonstrate that LSD is absorbed by C. elegans and that the acute treatment reduces animal speed, similar to the role of endogenous serotonin. This response is mediated in part by the serotonergic receptors SER-1 and SER-4. Our findings highlight the potential of this nematode as a new experimental model in psychedelic research.

Risk of unfavorable pain prognosis impacts walking physiomechanical parameters and psychophysiological workload in sufferers of chronic low back pain.

BACKGROUND: Tolerating physical tasks depends not only on task-specific characteristics but also on an individual's psychophysiological capacity to respond to the imposed load. People suffering from chronic low back pain (CLBP) may experience reduced psychophysiological capacity and are at risk for poor pain prognosis, which could lead to an increased walking workload. AIM: To investigate how the risk of unfavorable pain prognosis in CLBP can impact walking physiomechanical parameters and psychophysiological workload. METHODS: A cross-sectional observational study. The study classified 74 volunteers into four groups based on their prognosis for pain: pain-free control (CG/n = 20), low (LrG/n = 21), medium (MrG/n = 22), and high (HrG/n = 11) risk of poor prognosis for CLBP. The ground assessments identified the self-selected (SSW) and optimal (OWS) walking speeds, as well as the locomotor rehabilitation index (LRI). Treadmill assessments were conducted at two different speeds (0.83 and 1.11 m s-1, SSW and OWS) to record physiomechanical parameters. Psychophysiological workloads during walking were measured via workload impulse for the session (TRIMP), determined by variations in heart rate. RESULTS: CLBP groups exhibited slower SSW and lower LRI compared to the CG. The TRIMP was lower in the LrG. However, both MrG and HrG exhibited a comparable overload to the CG, even while walking at a lower intensity with a psychophysical demand. SSW and OWS displayed an increased TRIMP compared to fixed speeds. CONCLUSION: Psychosocial factors may affect SSW in people with CLBP but not among the risk strata. An unfavorable prognosis for pain could jeopardize the psychophysiological capacity to withstand walking demands.

Emergence of locomotor behaviors: Associations with infant characteristics, developmental status, parental beliefs, and practices in typically developing Brazilian infants aged 5 to 15 months.

Independent locomotion provides autonomy for infants, drastically changing their relationship with their surroundings. From a dynamic systems perspective, the interaction between environment, tasks, and organismic constraints leads to the emergence of new behaviors over time. This 6-month longitudinal study aimed to verify associations between the emergence of locomotor behaviors and infants' characteristics, developmental status, parental beliefs, and practices. This observational study remotely assessed 37 full-term Brazilian infants aged 5 to 15 months, divided into two groups (G1: 5 to 11 months, n = 19; and G2: 9 to 15 months, n = 18). The motor developmental status of infants was closely associated with the emergence of behaviors (p < 0.05). Infants in G2 whose parents agreed with the statement "In typically developing infants, motor development occurs naturally and there is no need to actively stimulate it" started to walk later than those whose parents disagreed. Infants whose parents expected them to walk around 10-11 months walked earlier compared to those expected to walk after 11 months (G2, p = 0.011). Infants in G2 with a high frequency of staying in the supine position started to walk, both with and without support, later than those with a low frequency (p < 0.05). For infants in G1 with a high frequency of playing on the floor, locomotion (p = 0.041) and crawling on hands-and-knees (p = 0.007) started sooner compared to those with a low frequency. Staying in the cradle more frequently was related to a later emergence of supported walk (p = 0.046) among infants in G2. The emergence of locomotor behaviors is associated with motor developmental status, the surfaces where the infant plays, and body position. Parental beliefs and expectations influence how infants are stimulated and, consequently, the emergence of independent walking.

Biomechanical modeling of musculoskeletal function related to the terrestrial locomotion of Riojasuchus tenuisceps (Archosauria: Ornithosuchidae).

Riojasuchus tenuisceps was a pseudosuchian archosaur from the Late Triassic period in Argentina. Like other ornithosuchids, it had unusual morphology such as a unique "crocodile-reversed" ankle joint, a lesser trochanter as in dinosaurs and a few other archosaurs, robust vertebrae, and somewhat shortened, gracile forelimbs. Such traits have fuelled controversies about its locomotor function-were its limbs erect or "semi-erect"? Was it quadrupedal or bipedal, or a mixture thereof? These controversies seem to persist because analyses have been qualitative (functional morphology) or correlative (morphometrics) rather than explicitly, quantitatively testing mechanistic hypotheses about locomotor function. Here, we develop a 3D whole-body model of R. tenuisceps with the musculoskeletal apparatus of the hindlimbs represented in detail using a new muscle reconstruction. We use this model to quantify the body dimensions and hindlimb muscle leverages of this enigmatic taxon, and to estimate joint ranges of motion and qualitative joint functions. Our model supports prior arguments that R. tenuisceps used an erect posture, parasagittal gait and plantigrade pes. However, some of our inferences illuminate the rather contradictory nature of evidence from the musculoskeletal system of R. tenuisceps-different features support (or are ambiguous regarding) quadrupedalism or bipedalism. Deeper analyses of our biomechanical model could move toward a consensus regarding ornithosuchid locomotion. Answering these questions would not only help understand the palaeobiology and bizarre morphology of this clade, but also more broadly if (or how) locomotor abilities played a role in the survival versus extinction of various archosaur lineages during the end-Triassic mass extinction event.

Acinonyx jubatus-Inspired Quadruped Robotics: Integrating Neural Oscillators for Enhanced Locomotion Control.

This study presents the design, simulation, and prototype creation of a quadruped robot inspired by the Acinonyx jubatus (cheetah), specifically designed to replicate its distinctive walking, trotting, and galloping locomotion patterns. Following a detailed examination of the cheetah's skeletal muscle anatomy and biomechanics, a simplified model of the robot with 12 degrees of freedom was conducted. The mathematical transformation hierarchy model was established, and direct kinematics were simulated. A bio-inspired control approach was introduced, employing a Central Pattern Generator model based on Wilson-Cowan neural oscillators for each limb, interconnected by synaptic weights. This approach assisted in the simulation of oscillatory signals for relative phases corresponding to four distinct gaits in a system-level simulation platform. The design phase was conducted using CAD software (SolidWorks 2018), resulting in a 1:3-scale robot mirroring the cheetah's actual proportions. Movement simulations were performed in a virtual mechanics software environment, leading to the construction of a prototype measuring 35.5 cm in length, 21 cm in width, 27 cm in height (when standing), and weighing approximately 2.1 kg. The experimental validation of the prototype's limb angular positions and trajectories was achieved through the image processing of video-recorded movements, demonstrating a high correlation (0.9025 to 0.9560) in joint angular positions, except for the knee joint, where a correlation of 0.7071 was noted. This comprehensive approach from theoretical analysis to practical implementation showcases the potential of bio-inspired robotics in emulating complex biological locomotion.

Investigation on the mancozeb toxicity in adult zebrafish (Danio rerio).

Agriculture has gained increasing importance in response to the continuous growth of the world population and constant need for food. To avoid production losses, farmers commonly use pesticides. Mancozeb is a fungicide used in agriculture as this compound is effective in combating fungi that harm crops. However, this fungicide may also produce damage to non-target organisms present in soil and water. Therefore, this study aimed to investigate the influence of exposure to mancozeb on survival rate, locomotor activity, behavior, and oxidative status utilizing adult zebrafish (Danio rerio) as a model following exposure to environmentally relevant concentrations of this pesticide. The experimental groups were negative control, positive control, and mancozeb (0.3; 1.02; 3.47; 11.8 or 40 µg/L). Zebrafish were exposed to the respective treatments for 96 hr. Exposure to mancozeb did not markedly alter survival rate and oxidative status of Danio rerio. At a concentration of 11.8 µg/L, the fungicide initiated changes in locomotor pattern of the animals. The results obtained suggest that the presence of mancozeb in the environment might produce locomotor alterations in adult zebrafish, which subsequently disrupt the animals' innate defense mechanisms. In nature, this effect attributed to mancozeb on non-target organisms might result in adverse population impacts and ecological imbalance.

The Midfoot Joint Complex (Foot Arch) Contributes to the Upper Body Position in Bipedal Walking and Coordinates With the Lower Limb Joints.

This study estimated the contribution of the midfoot joint complex (MJC) kinematics to the pelvis anterior-posterior positions during the stance phase of walking and investigated whether the MJC is functionally coordinated with the lower limb joints to maintain similar pelvic positions across steps. Hip, knee, ankle, and MJC sagittal angles were measured in 11 nondisabled participants during walking. The joints' contributions to pelvic positions were computed through equations derived from a link-segment model. Functional coordination across steps was identified when the MJC contribution to pelvic position varied and the summed contributions of other joints varied in the opposite direction (strong negative covariations [r ≤ -.7] in stance phase instants). We observed that the MJC plantarflexion (arch raising) during the midstance and late stance leads the pelvis backward, avoiding excessive forward displacement. The MJC was the second joint that contributed most to the pelvis positions (around 18% of all joints' contributions), after the ankle joint. The MJC and ankle were the joints that were most frequently coordinated with the other joints (≅70% of the stance phase duration). The findings suggest that the MJC is part of the kinematic chain that determines pelvis positions during walking and is functionally coordinated with the lower limb joints.

Interactive effects between water temperature, microparticle compositions, and fiber types on the marine keystone species Americamysis bahia.

Recently, there has been an increasing emphasis on examining the ecotoxicological effects of anthropogenic microparticles (MPs), especially microplastic particles, and related issues. Nevertheless, a notable deficiency exists in our understanding of the consequences on marine organisms, specifically in relation to microfibers and the combined influence of MPs and temperature. In this investigation, mysid shrimp (Americamysis bahia), an important species and prey item in estuarine and marine food webs, were subjected to four separate experimental trials involving fibers (cotton, nylon, polyester, hemp; 3 particles/ml; approximately 200 µm in length) or fragments (low-density Polyethylene: LDPE, polylactic acid: PLA, and their leachates; 5, 50, 200, 500 particles/ml; 1-20 µm). To consider the effects in the context of climate change, three different temperatures (22, 25, and 28 °C) were examined. Organismal growth and swimming behavior were measured following exposure to fragments and microfibers, and reactive oxygen species and particle uptake were investigated after microfiber exposure. To simulate the physical characteristics of MP exposure, such as microfibers obstructing the gills, we also assessed the post-fiber-exposure swimming behavior in an oxygen-depleted environment. Data revealed negligible fragment, but fiber exposure effects on growth. PLA leachate triggered higher activity at 25 °C and 28 °C; LDPE exposures led to decreased activity at 28 °C. Cotton exposures led to fewer behavioral differences compared to controls than other fiber types. The exposure to hemp fibers resulted in significant ROS increases at 28 °C. Microfibers were predominantly located within the gastric and upper gastrointestinal tract, suggesting extended periods of residence and the potential for obstructive phenomena over the longer term. The combination of increasing water temperatures, microplastic influx, and oxidative stress has the potential to pose risks to all components of marine and aquatic food webs.

Postural adjustments and perceptual responses of Nordic running: concurrent effects of poles and irregular terrain.

PURPOSE: In the natural environment, humans must continuously negotiate irregular and unpredictable terrain. Recently, the poles have been extensively used during trial running events. However, we know little about how humans adjust posture and bilateral coordination to use poles in irregular terrain. Here, we compared kinematics, bilateral coordination and perceptual responses between regular (compact dust) and irregular terrain (medium-length grass) during running at preferred speed with and without poles. METHODS: In this transversal observational study, thirteen young healthy adults (8 men; mean ± SD; age 29.1 ± 8.0 years, body mass 76.8 ± 11.4 kg; height 1.75 ± 0.08 m) were evaluated during running at a self-selected comfortable speed with and without poles on regular and irregular terrains. RESULTS: Our results show that, despite more flexed pattern on lower-limb joints at irregular terrain, the usage of poles was not enough to re-stabilize the bilateral coordination. Also, the perceived exertion was impaired adding poles to running, probably due to more complex movement pattern using poles in comparison to free running, and the invariance in the bilateral coordination. CONCLUSION: Besides the invariability of usage poles on bilateral coordination and lower-limb kinematics, the runners seem to prioritize postural stability over lower limb stiffness when running in medium-length grass given the larger range of ankle and knee motion observed in irregular terrain. Further investigations at rougher/hilly terrains will likely provide additional insights into the neuromotor control strategies used to maintain the stability and on perceptual responses using poles during running.

Enduring Ethanol-Induced Behavioral Alterations in Caenorhabditis elegans After Developmental Lead Exposure.

The roundworm Caenorhabditis elegans (C. elegans) has become a powerful tool to evaluate the deleterious effects of early-life exposure to xenobiotics, including metals. The present chapter describes a detailed protocol for developmental lead (Pb)-exposure in C. elegans. Preliminary assays as well as the final procedure are described in detail. In addition, further protocols aimed to assess ethanol exposure at later stages of life demonstrate the impact of this drug on locomotor behavior, revealing the enduring effects that Pb can imprint on this organism when exposure occurs during development.

Creatine supplementation increases postnatal growth and strength and prevents overexpression of pro-inflammatory interleukin 6 in the hippocampus in an experimental model of cerebral palsy.

ABSTRACTObjectives: The aim of this study was thus to evaluate the effect of Cr supplementation on morphological changes and expression of pro-inflammatory cytokines in the hippocampus and on developmental parameters. Methods: Male Wistar rat pups were submitted to an experimental model of CP. Cr was administered via gavage from the 21st to the 28th postnatal day, and in water after the 28th, until the end of the experiment. Body weight (BW), food consumption (FC), muscle strength, and locomotion were evaluated. Expression of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) were assessed in the hippocampus by quantitative real-time polymerase chain reaction. Iba1 immunoreactivity was assessed by immunocytochemistry in the hippocampal hilus. Results: Experimental CP caused increased density and activation of microglial cells, and overexpression of IL-6. The rats with CP also presented abnormal BW development and impairment of strength and locomotion. Cr supplementation was able to reverse the overexpression of IL-6 in the hippocampus and mitigate the impairments observed in BW, strength, and locomotion. Discussion: Future studies should evaluate other neurobiological characteristics, including changes in neural precursor cells and other cytokines, both pro- and anti-inflammatory.

Neonatal kaempferol exposure attenuates impact of cerebral palsy model on neuromotor development, cell proliferation, microglia activation, and antioxidant enzyme expression in the hippocampus of rats.

OBJECTIVES: This study aims to assess the effect of neonatal treatment with kaempferol on neuromotor development, proliferation of neural precursor cells, the microglia profile, and antioxidant enzyme gene expression in the hippocampus. METHODS: A rat model of cerebral palsy was established using perinatal anoxia and sensorimotor restriction of hindlimbs during infancy. Kaempferol (1 mg/ kg) was intraperitoneally administered during the neonatal period. RESULTS: Neonatal treatment with kaempferol reduces the impact of the cerebral palsy model on reflex ontogeny and on the maturation of physical features. Impairment of locomotor activity development and motor coordination was found to be attenuated by kaempferol treatment during the neonatal period in rats exposed to cerebral palsy. Neonatal treatment of kaempferol in cerebral palsy rats prevents a substantial reduction in the number of neural precursor cells in the dentate gyrus of the hippocampus, an activated microglia profile, and increased proliferation of microglia in the sub-granular zone and in the granular cell layer. Neonatal treatment with kaempferol increases gene expression of superoxide dismutase and catalase in the hippocampus of rats submitted to the cerebral palsy model. DISCUSSION: Kaempferol attenuates the impact of cerebral palsy on neuromotor behavior development, preventing altered hippocampal microglia activation and mitigating impaired cell proliferation in a neurogenic niche in these rats. Neonatal treatment with kaempferol also increases antioxidant defense gene expression in the hippocampus of rats submitted to the cerebral palsy model.

DMRT3 Allele Frequencies in Batida- and Picada-Gaited Donkeys and Mules in Brazil.

In Brazil, the production of mules with a comfortable gait primarily involves the breeding of marching saddle mules. This is achieved by crossing gaited Pêga donkeys with horses from the Mangalarga Marchador and Campolina breeds. The DMRT3:g.22999655C>A SNP is implicated in regulating gait phenotypes observed in various horse breeds, including the batida (CC) and picada (CA) gaits found in these horse breeds. We aimed to determine if genotypes influenced gait type in 159 mules and 203 donkeys genotyped for the DMRT3 SNP by PCR-RFLP analysis. About 47% of mules had the CC-genotype, while 53% had the CA-genotype. Donkeys predominantly had the CC-genotype (97%), and none had AA. Both CC- and CA-genotypes were evenly distributed among mules with the batida or picada gaits. In donkeys, the CC-genotype frequencies were consistent regardless of gait type. However, the CA-genotype was more common in picada-gaited donkeys than in batida-gaited donkeys. The prevalence of CA mules and the rare presence of the non-reference allele in donkeys align with previous findings in Mangalarga Marchador and Campolina horses. This suggests that the non-reference allele likely originated from the mares involved in donkey crosses. Our results also imply that factors beyond this variant, such as other genes and polymorphisms, influence gait traits in equids.

Walk Locomotion Kinematic Changes in a Model of Penetrating Hippocampal Injury in Male/Female Mice and Rats.

Traumatic brain injury has been the leading cause of mortality and morbidity in human beings. One of the most susceptible structures to this damage is the hippocampus due to cellular and synaptic loss and impaired hippocampal connectivity to the brain, brain stem, and spinal cord. Thus, hippocampal damage in rodents using a stereotaxic device could be an adequate method to study a precise lesion from CA1 to the dentate gyrus structures. We studied male and female rats and mice, analyzing hindlimb locomotion kinematics changes to compare the locomotion kinematics using the same methodology in rodents. We measure (1) the vertical hindlimb metatarsus, ankle, and knee joint vertical displacements (VD) and (2) the factor of dissimilarity (DF). The VD in intact rats in metatarsus, ankle, and knee joints differs from that in intact mice in similar joints. In rats, the vertical displacement through the step cycle changed in the left and right metatarsus, ankle, and knee joints compared to the intact group versus the lesioned group. More subtle changes were also observed in mice. DF demonstrates contrasting results when studying locomotion kinematics of mice or rats and sex-dependent differences. Thus, a precise lesion in a rodent's hippocampal structure discloses some hindlimb locomotion changes related to species and sex. Thus, we only have a qualitative comparison between murine species. In order to make a comparison with other species, we should standardize the model.

Locomotion behavior testing as a complementary tool in Collembola avoidance assays with neurotoxic insecticides.

This study aimed (1) to assess the ability of collembolans Folsomia candida to avoid soils contaminated with three seed dressing insecticides imidacloprid, clothianidin, and fipronil; (2) to assess the effects of the insecticides on collembolans' locomotion behavior; (3) to check if changes in the locomotion behavior would explain the avoidance/preference responses; and (4) to evaluate the possibility to use locomotion behavior as toxicity biomarker of the tested insecticides. Avoidance and locomotion behavior assays with collembolans F. candida were performed with commercial seed dressing formulations of three insecticides (imidacloprid, clothianidin, and fipronil). Results showed no avoidance behavior at any concentration, while a "preference" was observed with increasing concentrations of the three tested insecticides. Significant reductions in the locomotion of exposed collembolans were observed at ≥ 1 mg kg-1 for imidacloprid (18-38%) and fipronil (29-58%) and ≥ 4 mg kg-1 for clothianidin (10-47%). At the higher insecticide concentrations, the collembolans had their trajectories restricted to smaller areas, with a tendency for circular movements. Our results confirm that the "preference" for contaminated soils with neurotoxic substances is likely due to locomotion inhibition impairing the ability of organisms to escape. This effect highlights that only avoidance assays may be not sufficient to assure the safety of some substances and confirm the potential of locomotion behavior as a sensitive toxicity biomarker for neurotoxic insecticides.