Association between parent-proxy-reported and child-self-reported perceptions of children's motor competence and children's performance-based motor skill abilities

BACKGROUND

When assessing motor skills, occupational therapists are encouraged to seek the perspectives of children and their parents to promote the delivery of client-centered care.

AIM

To investigate whether 9-12-year-old children's views and their parents' proxy views of the children's motor skill competence and their performance on a standardized, performance-based assessment are associated.

MATERIALS AND METHODS

Thirty 9-12-year-old children completed the Perceived Motor Competence Questionnaire in Childhood (PMC-C) and the Pictorial Scale of Perceived Movement Skill Competence - version 2 (PMSC-2), while their parents completed the Movement Assessment Battery for Children-2nd Edition Checklist (MABC-2 Checklist). Children's objective motor skills were measured by the Bruininks-Oseretsky Test of Motor Proficiency-2nd Edition (BOT-2). Spearman's rho correlations were used to analyze the data.

RESULTS

Significant associations were found between the BOT-2 total motor composite and the PMC-C. A significant association was found between the MABC-2 Checklist and the BOT-2 Strength and Agility composite, as well as the PMC-C total score.

SIGNIFICANCE AND CONCLUSIONS

Occupational therapists are encouraged to include children and their parents in the therapeutic process to capture individual perspectives and deliver client-centered care.

Role of mu opioid receptor (MOR) agonist efficacy as a determinant of opioid antinociception in a novel assay of pain-depressed behavior in female and male mice

Introduction

Intermediate efficacy mu opioid receptor (MOR) agonists have potential to retain analgesic effectiveness while improving safety, but the optimal MOR efficacy for effective and safe opioid analgesia is unknown. Preclinical assays of pain-depressed behavior can assess effects of opioids and other candidate analgesics on pain-related behavioral depression, which is a common manifestation of clinically relevant pain and target of pain treatment. Accordingly, the present study goal was to validate a novel assay of pain-depressed locomotor behavior in mice and evaluate the role of MOR efficacy as a determinant of opioid analgesic effects and related safety measures.

Methods

Male and female ICR mice were tested in a locomotor chamber consisting of 2 compartments connected by a doorway that contained a 1-inch-tall barrier. Dependent measures during 15-min behavioral sessions included crosses between compartments (which required vertical activity to surmount the barrier) and total movement counts (which required horizontal activity to break photobeams in each compartment).

Results and Discussion

Intraperitoneal injection of lactic acid (IP acid) produced a concentration- and time-dependent depression of both endpoints. Optimal blockade of IP acid-induced behavioral depression with minimal motor impairment was achieved with intermediate-efficacy MOR treatments that also produced less gastrointestinal-transit inhibition and respiratory depression than the high-efficacy MOR agonist fentanyl. Sex differences in treatment effects were rare. Overall, these findings validate a novel procedure for evaluating opioids and other candidate analgesic effects on pain-related behavioral depression in mice and support continued research with intermediate-efficacy MOR agonists as a strategy to retain opioid analgesic effectiveness with improved safety.

Impact of COVID-19 Pandemic on Children's Fundamental Motor Skills: A Study for the Taiwanese Preschoolers Teachers

The outbreak of the COVID-19 pandemic has resulted in reduced opportunities for children to engage in fundamental motor skills [FMS]. This prolonged inactivity and restriction of play can have serious consequences for children's physical and mental health. The purpose of this study was to explore teaching strategies during the pandemic, whether there were differences in children's motor development, and the differences in the implementation of physical movement courses before and during the pandemic from the perspective of preschool teachers. This study was a retrospective study using an internet survey, and participants comprised 2337 preschool teachers. The statistical methodology of this study included descriptive statistics, the dependent t-test, and the independent t-test. The results showed that regardless of the time, frequency, activity intensity, and frequency of outdoor courses, the results from before the pandemic was better than those taken during the pandemic. Only the "frequency of implementing physical movement courses indoors every week" had not been affected by the pandemic. This study also obtained the performance of "children's fitness", "overall performance of physical movement ability", "stability movement skills", "locomotor movement skills", and "manipulative movement skills". All were better before the pandemic than during the pandemic. During the COVID-19 pandemic, mixed-age classes performed better than same-age classes in terms of frequency, time, intensity, outdoor course implementation, and physical fitness. Public schools performed better than private schools in terms of frequency, time, intensity, outdoor course implementation, and fundamental motor skills performance. Private schools implemented physical movement courses indoors every week, which was more than public schools. Excepting the frequency of implementing physical movement courses indoors every week, fewer than schools with five classes performed better than those who had more than schools with six classes. Finally, rural schools were better than urban schools in the implementation of outdoor courses and fundamental motor skills performance. Therefore, we suggest that in response to the pandemic, teachers should further improve their professionalism and use diversified teaching methods, and guide students to be willing to learn and improve their skill performance.

The Impact of Swimming on Fundamental Movement Skill Development in Children (3-11 Years): A Systematic Literature Review

Swimming is the only sport providing lifesaving skills, reducing the risk of death by drowning, a top cause of deaths in children aged 1-14 years. Research shows swimming amongst other sports can aid fundamental movement skill (FMS) development. Therefore, this review investigated the following: (1) how swimming impacts FMS development in children aged 3-11 years, (2) successful tools assessing swimming and FMS, and (3) recommendations appropriate to the UK curriculum based on findings of this study. A systematic literature review using Google Scholar, PubMed, and SPORTDiscuss was conducted to investigate the effects of swimming on FMS development. Methods included database searching, finalising articles appropriate to the inclusion and exclusion criteria, and identifying relevant articles using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The Mixed Methods Appraisal Tool assessed data quality and bias risk, whilst thematic analysis synthesised data alongside descriptive results. Ten papers were synthesised, identifying significant positive impacts of swimming on FMS, including significant pre-post testing (p < 0.01), significant improvements compared to other sports (p < 0.001), and significant improvements in specific motor skills (Balance; p = 0.0004). Future research specifically addressing swimming and FMS is essential to improving the curriculum.

One-year review of disability certificates issued by the neurology unit of a medical college in Maharashtra, India

In this article, we describe the profile of patients who were issued disability certificates from the neurology unit of a medical college in Maharashtra, India. In a retrospective cross-sectional study of 1-year duration, the demographic and clinical details of 102 participants were studied, of which 100 were issued the certificate. The mean age was 36 ± 14.04 years. There were more number of male applicants (65%) than females. Motor disability (71%) was the most common manifestation for which disability certificate was sought. Cerebral palsy was the most common etiology in the age group of <40 years, while stroke was the most common etiology in the age group >40 years. During our study period, four patients' diagnoses were changed during revisit. Additional studies are required to assess the causes of low female enrollment and lack of motivation to apply for the disability certificate at an earlier age.

Comparative Effectiveness of Physical Activity Intervention Programs on Motor Skills in Children and Adolescents: A Systematic Review and Network Meta-Analysis

Objective: To evaluate how different physical activity (PA) interventions (traditional, exergaming, and teacher/parent education) impacted children's motor skills (object control, locomotor, and gross motor). Design: Systematic review and network meta-analysis. Data sources: PubMed, Medline, Scopus, Web of Science, EMBASE, and PsycINFO. Eligibility criteria: (1) Participants comprised 1708 children 3-12 years; (2) PA or exercise-based interventions were investigated; (3) only studies using a Test of Gross Motor Skills assessment were included; (4) RCT were chosen as the study design to assess the impact of PA interventions on children's motor skills; and (5) culture-based PA studies with English language only were included. Data were analyzed using a Bayesian network meta-analysis. Results: The results were reported as standardized mean differences (SMDs) with associated 95% credible intervals (CrIs). For object control, aerobic intervention (SMD 6.90, 95% Crl 1.39 to 13.50); for locomotor, exergaming intervention (SMD 12.50, 95% Crl 0.28 to 24.50); and for gross motor, aerobic intervention (SMD 7.49, 95% Crl 0.11 to 15.70) were the most effective treatments. Conclusion: Children's FMSs have been improved through different PA interventions. Among them, aerobic interventions seem to be the most effective intervention in enhancing object control skills and overall gross motor skills.

Cocaine increases quantal norepinephrine secretion through NET-dependent PKC activation in locus coeruleus neurons

The norepinephrine neurons in locus coeruleus (LC-NE neurons) are essential for sleep arousal, pain sensation, and cocaine addiction. According to previous studies, cocaine increases NE overflow (the profile of extracellular NE level in response to stimulation) by blocking the NE reuptake. NE overflow is determined by NE release via exocytosis and reuptake through NE transporter (NET). However, whether cocaine directly affects vesicular NE release has not been directly tested. By recording quantal NE release from LC-NE neurons, we report that cocaine directly increases the frequency of quantal NE release through regulation of NET and downstream protein kinase C (PKC) signaling, and this facilitation of NE release modulates the activity of LC-NE neurons and cocaine-induced stimulant behavior. Thus, these findings expand the repertoire of mechanisms underlying the effects of cocaine on NE (pro-release and anti-reuptake), demonstrate NET as a release enhancer in LC-NE neurons, and provide potential sites for treatment of cocaine addiction.

Behavioral effects of ethanol in the Red Swamp Crayfish (Procambarus clarkii)

Alcohol abuse remains one of the primary preventable sources of mortality in the United States. Model species can be used to evaluate behavioral and other biological changes associated with alcohol and to identify novel treatments. This report describes methods for evaluating the behavioral effects of ethanol (EtOH) in crayfish. Crayfish (Procambarus clarkii) were immersed in ethanol concentrations ranging from 0.1 to 1.0 molar, for 10-30 min. Studies evaluated hemolymph alcohol concentration, locomotion in an open field and anxiety-like behavior using a Light/Dark transfer approach. EtOH immersion produced dose-dependent increases in hemolymph EtOH (up to 249 mg/dL) and reductions in open field locomotion that depended on EtOH concentration or exposure duration. Untreated crayfish exhibit avoidance of the open parts of the locomotor arena and a preference for a covered portion. Acute EtOH immersion decreased time spent in the covered portion of the Light/Dark arena, consistent with a decrease in anxiety-like behavior. Daily EtOH immersion for 5 days did not alter locomotor responses, however, activity was increased 3 days after the repeated EtOH regimen. Overall, this study shows that this inexpensive, easily maintained species can be used for behavioral pharmacological experiments designed to assess the acute and repeated effects of EtOH.

Ultrasound evaluation of digital flexor tendons of jumping horses undergoing treadmill training

This study aimed to perform ultrasonographic evaluation of the digital flexor tendons of jumping horses undergoing complementary training on a treadmill. Fifteen Brazilian Sport horses were divided into two groups: Group I with 7 animals in physical training complementary to the standard training at the Brazilian Army's Riding School; and Group II with 8 animals in standard training used in the Brazilian Army's Riding School. Complementary training was performed on a treadmill on an inclined plane. Ultrasonographic images were taken at the beginning and at the end of training. The left thoracic and pelvic limbs of horses were evaluated for echogenicity values and cross-sectional areas of the superficial digital flexor tendons (SDFTs) and deep digital flexor tendons (DDFTs) in zones IA, IIB, and IIIB. The mean areas of the SDFT were 93.7 mm² and 95.8 mm² at the beginning and the end of training, respectively. The cross-sectional area of DDFT increased from 124.6 mm² at the beginning of training to 136.8 mm² at the end of training. The echogenicity values of both tendons were between 0 and 1 as expected, concluding that clinically, the animals showed adaptation to the exercise protocol with no signs of tendon injury being detected, implying that traditional training and complementary training are safe.

Effects of Early Motor Interventions on Gross Motor and Locomotor Development for Infants at-Risk of Motor Delay: A Systematic Review

AIM

To systematically examine the effect of early motor interventions on motor and locomotor development in infants <1 year of age with motor developmental disability or at risk of motor delay.

METHODS

Pertinent literature from January 2000 to September 2021 was identified by searching the PubMed, Embase, Cochrane, Pedro and Web of Science databases. Selection criteria included interventions starting before 12 months corrected age. Methodological quality was assessed with AACPDM criteria, Mallen score and Cochrane risk of bias methodology. Evaluation procedure was performed using PRISMA protocol (PICO approach) and AMSTAR-2. This review was preregistered in PROSPERO (CRD42021286445).

RESULTS

Ten articles met the inclusion criteria; seven had moderate to strong methodological quality. The interventions included treadmill training (n = 3), crawling training (n = 1), "tummy time" (n = 1), physical therapy with neonatal developmental program (n = 1) or Bobath approach (n = 1), treadmill training combined with active leg movements (n = 2) or Bobath physiotherapy (n = 1). The three key characteristics of effective interventions that emerged from the review were: (1) the infants' disability or risk of delay was well-defined; (2) the protocol was standardized and easy to replicate; (3) infants were required to make active movements.

CONCLUSION

There is an urgent need for additional high-quality studies on the effects of early motor interventions on the gross motor and locomotor development of infants with a range of disabilities or risks for delay. Suggestions for future research are outlined.

Establishing Equivalent Aerobic Exercise Parameters Between Early-Stage Parkinson's Disease and Pink1 Knockout Rats

BACKGROUND

Rodent Parkinson's disease (PD) models are valuable to interrogate neurobiological mechanisms of exercise that mitigate motor impairment. Translating these mechanisms to human PD must account for physical capabilities of the patient.

OBJECTIVE

To establish cardiovascular parameters as a common metric for cross-species translation of aerobic exercise impact.

METHOD

We evaluated aerobic exercise impact on heart rate (HR) in 21 early-stage PD subjects (Hoehn Yahr ≤1.5) exercising in non-contact boxing training for ≥3 months, ≥3x/week. In 4-month-old Pink1 knockout (KO) rats exercising in a progressively-increased treadmill speed regimen, we determined a specific treadmill speed that increased HR to an extent similar in human subjects.

RESULTS

After completing aerobic exercise for ∼30 min, PD subjects had increased HR∼35% above baseline (∼63% maximum HR). Motor and cognitive test results indicated the exercising subjects completed the timed up and go (TUG) and trail-making test (TMT-A) in significantly less time versus exercise-naïve PD subjects. In KO and age-matched wild-type (WT) rats, treadmill speeds of 8-10 m/min increased HR up to 25% above baseline (∼67% maximum HR), with no further increases up to 16 m/min. Exercised KO, but not WT, rats showed increased locomotor activity compared to an age-matched exercise-naïve cohort at 5 months old.

CONCLUSION

These proof-of-concept results indicate HR is a cross-species translation parameter to evaluate aerobic exercise impact on specific motor or cognitive functions in human subjects and rat PD models. Moreover, a moderate intensity exercise regimen is within the physical abilities of early-stage PD patients and is therefore applicable for interrogating neurobiological mechanisms in rat PD models.

Magnolol attenuates the locomotor impairment, cognitive deficit, and neuroinflammation in Alzheimer's disease mice with brain insulin resistance via up-regulating miR-200c

In this study, we aimed to investigate the effect of Magnolol on Alzheimer’s disease (AD). After the model of streptozotocin-induced AD mice with brain insulin resistance was established, the mice were treated with Magnolol or miR-200c antagomiR. The abilities of ambulations, rearings, discrimination, spatial learning, and memory were evaluated by open-field test (OFT), novel object recognition (NOR), and morris water maze (MWM) tests. The levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and miR-200c in the mice hippocampus were evaluated by enzyme-linked immunosorbent assay, Western blot, or Quantitative real-time Polymerase Chain Reaction. In AD mice model, streptozotocin induced the locomotor impairment and cognitive deficit, up-regulated levels of MDA, TNF-α, IL-6, and CRP, while down-regulated levels of GSH, SOD, and miR-200c. Magnolol increased the rearings numbers and discrimination index of AD mice in OFT and NOR tests. Magnolol increased the number of entries in the target quadrant and time spent in the target quadrant and decreased the escape latency of AD mice in the MWM test. Magnolol also down-regulated the levels of MDA, TNF-α, IL-6, and CRP, and up-regulated the levels of GSH, SOD, and miR-200c in the hippocampus tissues of AD mice. However, miR-200c antagomiR did the opposite and further offset the effects of the Magnolol on AD mice. Magnolol attenuated the locomotor impairment, cognitive deficit, and neuroinflammatory in AD mice with brain insulin resistance via up-regulating miR-200c.

Fundamental Motor Skill Delays in Preschool Children With Disabilities: 2012 National Youth Fitness Survey

Delays in fundamental motor skill (FMS) competency have been observed in a variety of children with disabilities. However, evidence of FMS delays is largely limited to small, geographically specific, limitedly diverse, and non-representative samples. The purpose of this study was to examine the association between FMS competency and reported disability status among pre-school children, ages 3–5 years, using the 2012 National Youth Fitness Survey (NYFS). In total, 329 preschool children (49% female; 4.00 ± 0.04 years of age) from the 2012 NYFS completed the Test of Gross Motor Development−2, including 43 preschoolers identified with a disability based on parental report (44% female; 4.20 ± 0.16 years). Associations were examined with logistic regression using sampling weights. Poor FMS competency, defined as gross motor quotient scores ≤ 79, was observed in significantly more children with disabilities (29%) than children without disabilities (10%, OR = 3.5, p = 0.04). While not statistically significant, there was a growing disparity in FMS competency at age 5 (41 vs. 11%) compared to age 3 (15 vs. 9%, OR = 1.80, p = 0.30). The results provide additional evidence for poor FMS competency among pre-school children with disabilities. FMS should be an early part of comprehensive assessments for all children suspected of disability or development delay as it is critical to identify and intervene upon FMS delays before discrepancies can widen.

Conservation of locomotion-induced oculomotor activity through evolution in mammals

Efference copies are neural replicas of motor outputs used to anticipate the sensory consequences of a self-generated motor action or to coordinate neural networks involved in distinct motor behaviors.¹ An established example of this motor-to-motor coupling is the efference copy of the propulsive motor command, which supplements classical visuo-vestibular reflexes to ensure gaze stabilization during amphibian larval locomotion.² Such feedforward replica of spinal pattern-generating circuits produces a spino-extraocular motor coupled activity that evokes eye movements, spatiotemporally coordinated to tail undulation independently of any sensory signal.^3,4 Exploiting the developmental stages of the frog,¹ studies in metamorphing Xenopus demonstrated the persistence of this spino-extraocular motor command in adults and its developmental adaptation to tetrapodal locomotion.^5,6 Here, we demonstrate for the first time the existence of a comparable locomotor-to-ocular motor coupling in the mouse. In neonates, ex vivo nerve recordings of brainstem-spinal cord preparations reveal a spino-extraocular motor coupled activity similar to the one described in Xenopus. In adult mice, trans-synaptic rabies virus injections in lateral rectus eye muscle label cervical spinal cord neurons closely connected to abducens motor neurons. Finally, treadmill-elicited locomotion in decerebrated preparations⁷ evokes rhythmic eye movements in synchrony with the limb gait pattern. Overall, our data are evidence for the conservation of locomotor-induced eye movements in vertebrate lineages. Thus, in mammals as in amphibians, CPG-efference copy feedforward signals might interact with sensory feedback to ensure efficient gaze control during locomotion.

Functional validation of a finding from a mouse genome-wide association study shows that Azi2 influences the acute locomotor stimulant response to methamphetamine

In a previous genome-wide association study (GWAS) using outbred Carworth Farms White (CFW) mice, we identified a locus that influenced the stimulant response to methamphetamine and colocalized with an eQTL for Azi2. Based on those findings, we hypothesized that heritable differences in Azi2 expression were causally related to the differential response to methamphetamine. To test that hypothesis, we created a mutant Azi2 allele on an inbred C57BL/6J background. The mutant allele enhanced the locomotor response to methamphetamine. However, the GWAS had suggested that lower Azi2 would decrease the locomotor response to methamphetamine. We also sought to explore the mechanism by which Azi2 influenced methamphetamine sensitivity. A recent publication reported that the 3'UTR of Azi2 mRNA downregulates the expression of Slc6a3, which encodes the dopamine transporter, which is a key target of methamphetamine. We evaluated the relationship between Azi2, Azi2 3'UTR and Slc6a3 expression in the ventral tegmental area of wildtype, mutant Azi2 heterozygotes and mutant Azi2 homozygotes and in a new cohort of outbred CFW mice where both allele mapped in our prior GWAS were segregating. We did not observe any correlation between Azi2 and Slc6a3 in either cohort. However, RNA sequencing confirmed that the Azi2 mutation altered Azi2 expression and also revealed a number of potentially important genes and pathways that were regulated by Azi2, including the metabotropic glutamate receptor group III pathway and nicotinic acetylcholine receptor signaling pathway. Our results support a role for Azi2 in methamphetamine sensitivity; however, the exact mechanism does not appear to involve regulation of Slc6a3.

Force-Control vs. Strength Training: The Effect on Gait Variability in Stroke Survivors

Purpose: Increased gait variability in stroke survivors indicates poor dynamic balance and poses a heightened risk of falling. Two primary motor impairments linked with impaired gait are declines in movement precision and strength. The purpose of the study is to determine whether force-control training or strength training is more effective in reducing gait variability in chronic stroke survivors.

Methods: Twenty-two chronic stroke survivors were randomized to force-control training or strength training. Participants completed four training sessions over 2 weeks with increasing intensity. The force-control group practiced increasing and decreasing ankle forces while tracking a sinusoid. The strength group practiced fast ankle motor contractions at a percentage of their maximal force. Both forms of training involved unilateral, isometric contraction of the paretic, and non-paretic ankles in plantarflexion and dorsiflexion. Before and after the training, we assessed gait variability as stride length and stride time variability, and gait speed. To determine the task-specific effects of training, we measured strength, accuracy, and steadiness of ankle movements.

Results: Stride length variability and stride time variability reduced significantly after force-control training, but not after strength training. Both groups showed modest improvements in gait speed. We found task-specific effects with strength training improving plantarflexion and dorsiflexion strength and force control training improving motor accuracy and steadiness.

Conclusion: Force-control training is superior to strength training in reducing gait variability in chronic stroke survivors. Improving ankle force control may be a promising approach to rehabilitate gait variability and improve safe mobility post-stroke.

Effects of Traditional Indian Dance on Motor Skills and Balance in Children with Down syndrome

The objective of the study was to examine the effects of traditional Indian dances like Bharatanatyam, Kuchipudi and Kathak on motor skills and balance in children with Down syndrome compared to neuromuscular training. In this randomised double-arm design, 36 children with Down syndrome aged 6-10 years and with a score of <5 in Beighton's hypermobility test participated in either Indian classical dance (n = 18) or neuromuscular training (n = 18). Both the groups practised an hour-long session a day, three days a week for six weeks in six special-schools. Test of Gross Motor Development-2 (TGMD-2), Four Square Step Test (FSST) and paediatric balance scale were the outcome measures. After six weeks of training, there is a significant group difference of change score in the Gross Motor Quotient standard score of TGMD-2 [experimental: 30.47 vs. control: 11.1], locomotor subset of TGMD-2 [experimental: 11.1 vs. control: 4.35] and FSST [experimental: 4.29 vs. control: 2.41], but not in the paediatric balance scale [experimental: 3.59 vs. control: 3.76]. The traditional Indian dance substantially improved the locomotor skills of children with Down syndrome than that of neuromuscular exercises. Both the dance and neuromuscular training equally impacted the balance capacity.

Loss of parla Function Results in Inactivity, Olfactory Impairment, and Dopamine Neuron Loss in Zebrafish

The presenilin-associated rhomboid-like (PARL) gene was found to contribute to mitochondrial morphology and function and was linked to familial Parkinson's disease (PD). The PARL gene product is a mitochondrial intramembrane cleaving protease that acts on a number of mitochondrial proteins involved in mitochondrial morphology, apoptosis, and mitophagy. To date, functional and genetic studies of PARL have been mainly performed in mammals. However, little is known about PARL function and its role in dopaminergic (DA) neuron development in vertebrates. The zebrafish genome comprises two PARL paralogs: parla and parlb. Here, we established a loss-of-function mutation in parla via CRISPR/Cas9-mediated mutagenesis. We examined DA neuron numbers in the adult brain and expression of genes associated with DA neuron function in larvae and adults. We show that loss of parla function results in loss of DA neurons, mainly in the olfactory bulb. Changes in the levels of tyrosine hydroxylase transcripts supported this neuronal loss. Expression of fis1, a gene involved in mitochondrial fission, was increased in parla mutants. Finally, we showed that loss of parla function translates into impaired olfaction and altered locomotion parameters. These results suggest a role for parla in the development and/or maintenance of DA neuron function in zebrafish.

Pharmacokinetic and pharmacodynamic analyses of cocaine and its metabolites in behaviorally divergent inbred mouse strains

Cocaine (COC) is a psychostimulant with a high potential for abuse and addiction. Risk for COC use disorder is driven, in part, by genetic factors. Animal models of addiction-relevant behaviors have proven useful for studying both genetic and nongenetic contributions to drug response. In a previous study, we examined initial locomotor sensitivity to COC in genetically diverse inbred mouse strains. That work highlighted the relevance of pharmacokinetics (PK) in initial locomotor response to COC but was limited by a single dose and two sampling points. The objective of the present study was to characterize the PK and pharmacodynamics of COC and its metabolites (norcocaine and benzoylecgonine) in six inbred mouse strains (I/LnJ, C57BL/6J, FVB/NJ, BTBR T+ tf/J, LG/J and LP/J) that exhibit extreme locomotor responses to cocaine. Mice were administered COC at one of four doses and concentrations of cocaine, norcocaine and benzoylecgonine were analyzed in both plasma and brain tissue at 5 different time points. Initial locomotor sensitivity to COC was used as a pharmacodynamic endpoint. We developed an empirical population PK model that simultaneously characterizes cocaine, norcocaine and benzoylecgonine in plasma and brain tissues. We observed interstrain variability occurring in the brain compartment that may contribute to pharmacodynamic differences among select strains. Our current work paves the way for future studies to explore strain-specific pharmacokinetic differences and identify factors other than PK that are responsible for the diverse behavioral response to COC across these inbred mouse strains.

Theacrine From Camellia kucha and Its Health Beneficial Effects

Theacrine, i.e., 1,3,7,9-tetramethyluric acid, is one of the major purine alkaloids found in leaf of a wild tea plant species Camellia kucha Hung T. Chang. Theacrine has been attracted great attentions academically owing to its diverse health benefits. Present review examines the advances in the research on the health beneficial effects of theacrine, including antioxidant effect, anti-inflammatory effect, locomotor activation and reducing fatigue effects, improving cognitive effect, hypnotic effect, ameliorating lipid metabolism and inhibiting breast cancer cell metastasis effect. The inconsistent results in this research field and further expectations were also discussed.

Fetal Bisphenol-A Induced Changes in Murine Behavior and Brain Gene Expression Persisted in Adult-aged Offspring

In utero Bisphenol A (BPA) exposure has been linked to many deficits during brain development, including sexual differentiation, behavior, and motor coordination. Yet, how BPA induces these disorders and whether its effects are long lasting are largely unknown. In this study, using a mouse model, we demonstrated that in utero exposure to an environmentally relevant dose of BPA induced locomotor deficits, anxiety-like behavior, and declarative memory impairments that persisted into old age (18 months). Compared to the control animals, the BPA-exposed mice had a significant decrease in locomotor activity, exploratory tendencies, and long-term memory, and an increase in anxiety. The global brain gene expression profile was altered permanently by BPA treatment and showed regional and sexual differences. The BPA-treated male mice had more changes in the hippocampus, while female mice experienced more changes in the cortex. Overall, we demonstrate that in utero exposure to BPA induces permanent changes in brain gene expression in a region-specific and sex-specific manner, including a significant decrease in locomotor activity, learning ability, long-term memory, and an increase in anxiety. Fetal/early life exposures permanently affect neurobehavioral functions that deteriorate with age; BPA exposure may compound the effects of aging.

Long-Lasting Impact of Maternal Immune Activation and Interaction With a Second Immune Challenge on Pig Behavior

The combined effects on pig behavior of maternal immune challenge during gestation followed by a second immune challenge later in life have not been studied. Porcine reproductive and respiratory syndrome virus (PRRSV) infection during gestation can elicit maternal immune activation (MIA) yet the interactions with the offspring response to a second immune challenge after birth remains unexplored. Knowledge on the response to viral challenges in rodents has been gained through the use of the viral mimetic polyinosinic-polycytidylic acid (Poly(I:C)), yet the effects of this immune stimulant on pig behavior have not been assessed. This study advances the understanding of the combined effect of MIA and a second immune challenge later in life on female and male pig behavior. Three complementary experiments enabled the development of an effective Poly(I:C) challenge in pigs, and testing the interaction between PRRSV-elicited MIA, Poly(I:C) challenge at 60 days of age, and sex on behaviors. Individual-level observations on sickness, locomotor, and social behaviors were measured 1-3 h after Poly(I:C) challenge. Vomiting, panting, lethargy, walking, laying, playing, and touching behaviors were analyzed using generalized linear mixed effect models. Results indicated that a Poly(I:C) dose of 1 mg/kg within 1 h after injection increased the incidence of laying and sickness behavior. The Poly(I:C) challenge decreased the incidence of locomotor behaviors and activity levels. Pigs exposed to MIA had lower rates of social behaviors such as playing. The combined effect of PRRSV-elicited MIA and Poly(I:C) immune challenge further sensitized the pigs to behavior disruption across sexes including changes in sternal and lateral laying, walking, lethargy, and touching incidence. Notably, the effects of Poly(I:C) immune challenge alone on behaviors tended to be more extreme in males, whereas the effects of Poly(I:C) following MIA tended to be more extreme in females. Our findings demonstrate that MIA and Poly(I:C) affected behaviors, and the viral mimetic effects shortly after injection can offer insights into the prolonged effect of postnatal viral infections on feeding, social interactions and health status. Management practices that reduce the likelihood of gestational diseases and accommodate for behavioral disruptions in the offspring can minimize the impact of MIA.

Sex differences in fatigability following exercise normalised to the power-duration relationship

KEY POINTS

Knee-extensors demonstrate greater fatigue resistance in females compared to males during single-limb and whole-body exercise. For single-limb exercise, the intensity-duration relationship is different between sexes, with females sustaining a greater relative intensity of exercise. This study established the power-duration relationship during cycling, then assessed fatigability during critical power-matched exercise within the heavy and severe intensity domains. When critical power and the curvature constant were expressed relative to maximal ramp test power, no sex difference was observed. No sex difference in time to task failure was observed in either trial. During heavy and severe intensity cycling, females experienced lesser muscle de-oxygenation. Following both trials, females experienced lesser reductions in knee-extensor contractile function, and following heavy intensity exercise, females experienced less reduction in voluntary activation. These data demonstrate that whilst the relative power-duration relationship is not different between males and females, the mechanisms of fatigability during critical power-matched exercise are mediated by sex.

ABSTRACT

Due to morphological differences, females demonstrate greater fatigue resistance of locomotor muscle during single-limb and whole-body exercise modalities. Whilst females sustain a greater relative intensity of single-limb, isometric exercise than males, limited investigation has been performed during whole-body exercise. Accordingly, this study established the power-duration relationship during cycling in 18 trained participants (eight females). Subsequently, constant-load exercise was performed at critical power (CP)-matched intensities within the heavy and severe domains, with the mechanisms of fatigability assessed via non-invasive neurostimulation, near-infrared spectroscopy and pulmonary gas exchange during and following exercise. Relative CP (72 ± 5 vs. 74 ± 2% P_max , P = 0.210) and curvature constant (51 ± 11 vs. 52 ± 10 J P_max ^-1 , P = 0.733) of the power-duration relationship were similar between males and females. Subsequent heavy (P = 0.758) and severe intensity (P = 0.645) exercise time to task failures were not different between sexes. However, females experienced lesser reductions in contractile function at task failure (P ≤ 0.020), and greater vastus lateralis oxygenation (P ≤ 0.039) during both trials. Reductions in voluntary activation occurred following both trials (P < 0.001), but were less in females following the heavy trial (P = 0.036). Furthermore, during the heavy intensity trial only, corticospinal excitability was reduced at the cortical (P = 0.020) and spinal (P = 0.036) levels, but these reductions were not sex-dependent. Other than a lower respiratory exchange ratio in the heavy trial for females (P = 0.039), no gas exchange variables differed between sexes (P ≥ 0.052). Collectively, these data demonstrate that whilst the relative power-duration relationship is not different between males and females, the mechanisms of fatigability during CP-matched exercise above and below CP are mediated by sex.

Drug Conditioning and Sensitization in Mice: Importance of Early Voluntary Exercise

The timing of voluntary exercise relative to drug conditioning is important to its "neuroprotective" effects, though it is unclear whether the voluntary exercise needs to occur temporally contiguous with drug conditioning, or occur during an early, developmental period, but non-contiguous with drug conditioning, for its "neuroprotective" effects. To distinguish between these two ideas, the timing of voluntary exercise relative to drug conditioning on the development and extinction of conditioned hyperactivity, and induction of sensitization was manipulated in the present experiment. Specifically, half of the exercise mice were permitted access to home-cage running wheels for 6 continuous weeks (Exercise-Exercise) whereas the other half of the exercise mice were permitted access to home-cage running wheels only for the first 3  weeks and then had the wheels removed (Exercise-Sedentary). Likewise, half of the sedentary mice had no home-cage running wheels for 6 continuous weeks (Sedentary-Sedentary) whereas the other half of the sedentary mice were permitted access to the home-cage running wheels for the last 3 weeks prior to the acquisition phase (Sedentary-Exercise). Mice received vehicle or methamphetamine (Meth; 1.0 mg/kg; acquisition), followed by saline-alone sessions (extinction) and finally challenged with an escalating Meth-regimen (0.25 → 1.0 mg/kg). While all Meth-paired groups, regardless of exercise regimen, showed conditioned hyperactivity, Exercise-Exercise and Exercise-Sedentary mice were less responsive to chronic Meth exposure and showed slower extinction compared to the other Meth-paired groups. These results suggest an early exercise regimen, during a critical developmental window, protects against the stimulant properties of Meth and simultaneously facilitates contextual learning.

Locomotor characteristics of the women's inaugural super league competition and the rugby league world cup

Understanding the locomotor characteristics of competition can help rugby league (RL) coaches optimise training prescription. To date, no research exists on the locomotor characteristics of women's RL. The aim was to compare whole match and peak locomotor characteristics of women's RL competition at international (RL World Cup [WRLWC]) and domestic level (Super League [WSL]). Microtechnology data were collected from 58 players from 3-WSL clubs and 1-WRLWC team. Participants were classified into forwards (n = 30) and backs (n = 28). Partial least squares correlation analysis established which variables were important to discriminate between the level of competition (international vs. domestic) and positional group (forwards vs. backs). Linear mixed-effects models estimated the differences between standards of competition and positional group for those variables. International forwards were most likely exposed to greater peak 1-min average acceleration (standardised mean difference = 1.23 [0.42 to 2.04]) and peak 3-min average acceleration (1.13 [0.41 to 1.85]) than domestic forwards. International backs likely completed greater peak 1-min average acceleration (0.83 [0.08 to 1.58]) than domestic backs and possibly greater high-speed-distances (0.45 [-0.17 to 1.07]). Findings highlight the need for positional specific training across levels to prepare representative players for the increased match characteristics of international competition.

Socioeconomic and Familial Factors Associated with Gross Motor Skills among US Children Aged 3-5 Years: The 2012 NHANES National Youth Fitness Survey

The first aim of this study was to examine the prevalence of below average gross motor skills in a representative sample of US children aged 3 to 5 years. The second aim was to identify socioeconomic and familial characteristics that are associated with below average gross motor skills. Secondary analysis was conducted using the datasets from the 2012 National Health and Examination Survey National Youth Fitness Survey (NNYFS). The NNYFS assessed gross motor skills among 329 children aged 3-5 years, using the Test of Gross Motor Development-Second Edition (TGMD-2). Socioeconomic and familial characteristics of interest, such as family income and family structure, were asked in an in-person interview. This study estimated that one in three US children age 3 to 5 years old (33.9%) scored below average for gross motor quotient. In the gross motor subsets, one in four (24.4%) scored below average for locomotion and two in five (39.9%) scored below average for object control. Children living below the poverty threshold were more likely to have a higher gross motor quotient (odds ratio, OR = 2.76; 95% confidence interval, CI = 1.09-7.00). Girls were more likely to have a higher locomotor score (OR = 2.17; 95% CI = 1.10-4.25). Those living with other child(ren) aged ≤5 years were more likely to have a higher locomotor score (OR = 2.36; 95% CI = 1.01-5.54), while those living with child(ren) aged 6-17 years were more likely to have a higher object control score (OR = 1.83; 95% CI = 1.24-2.69). This study revealed risk factors associated with poor gross motor development, furthering our understanding of gross motor development in early childhood.

Norpa Signalling and the Seasonal Circadian Locomotor Phenotype in Drosophila

In this paper, we review the role of the norpA-encoded phospholipase C in light and thermal entrainment of the circadian clock in Drosophila melanogaster. We extend our discussion to the role of norpA in the thermo-sensitive splicing of the per 3′ UTR, which has significant implications for seasonal adaptations of circadian behaviour. We use the norpA mutant-generated enhancement of per splicing and the corresponding advance that it produces in the morning (M) and evening (E) locomotor component to dissect out the neurons that are contributing to this norpA phenotype using GAL4/UAS. We initially confirmed, by immunocytochemistry and in situ hybridisation in adult brains, that norpA expression is mostly concentrated in the eyes, but we were unable to unequivocally reveal norpA expression in the canonical clock cells using these methods. In larval brains, we did see some evidence for co-expression of NORPA with PDF in clock neurons. Nevertheless, downregulation of norpA in clock neurons did generate behavioural advances in adults, with the eyes playing a significant role in the norpA seasonal phenotype at high temperatures, whereas the more dorsally located CRYPTOCHROME-positive clock neurons are the likely candidates for generating the norpA behavioural effects in the cold. We further show that knockdown of the related plc21C encoded phospholipase in clock neurons does not alter per splicing nor generate any of the behavioural advances seen with norpA. Our results with downregulating norpA and plc21C implicate the rhodopsins Rh2/Rh3/Rh4 in the eyes as mediating per 3′ UTR splicing at higher temperatures and indicate that the CRY-positive LNds, also known as ‘evening’ cells are likely mediating the low-temperature seasonal effects on behaviour via altering per 3′UTR splicing.

The Effects of Combined Movement and Storytelling Intervention on Motor Skills in South Asian and White Children Aged 5-6 Years Living in the United Kingdom

Early motor development has an important role in promoting physical activity (PA) during childhood and across the lifespan. Children from South Asian backgrounds are less active and have poorer motor skills, thus identifying the need for early motor skill instruction. This study examines the effect of a movement and storytelling intervention on South Asian children’s motor skills. Following ethics approval and consent, 39 children (46% South Asian) participated in a 12-week movement and storytelling intervention. Pre and post, seven motor skills (run, jump, throw, catch, stationary dribble, roll, and kick) were assessed using Children’s Activity and Movement in Preschool Study protocol. At baseline, South Asian children had poorer performance of motor skills. Following the intervention, all children improved their motor skills, with a bigger improvement observed for South Asian children. Early intervention provided remedial benefits to delays in motor skills and narrowed the motor skills gap in ethnic groups.

No evidence for neonicotinoid preferences in the bumblebee Bombus impatiens

Neonicotinoid pesticides can have a multitude of negative sublethal effects on bees. Understanding their impact on wild populations requires accurately estimating the dosages bees encounter under natural conditions. This is complicated by the possibility that bees might influence their own exposure: two recent studies found that bumblebees (Bombus terrestris) preferentially consumed neonicotinoid-contaminated nectar, even though these chemicals are thought to be tasteless and odourless. Here, we used Bombus impatiens to explore two elements of these reported preferences, with the aim of understanding their ecological implication and underlying mechanism. First, we asked whether preferences persisted across a range of realistic nectar sugar concentrations, when measured at a series of time points up until 24 h. Second, we tested whether bees' neonicotinoid preferences were driven by an ability to associate their post-ingestive consequences with floral stimuli such as colour, location or scent. We found no evidence that foragers preferred to consume neonicotinoid-containing solutions, despite finding effects on feeding motivation and locomotor activity in line with previous work. Bees also did not preferentially visit floral stimuli previously paired with a neonicotinoid-containing solution. These results highlight the need for further research into the mechanisms underlying bees' responses to these pesticides, critical for determining how neonicotinoid-driven foraging preferences might operate in the real world for different bee species.

Disrupted Glutamate Signaling in Drosophila Generates Locomotor Rhythms in Constant Light

We have used the Cambridge Protein Trap resource (CPTI) to screen for flies whose locomotor rhythms are rhythmic in constant light (LL) as a means of identifying circadian photoreception genes. From the screen of ∼150 CPTI lines, we obtained seven hits, two of which targeted the glutamate pathway, Got1 (Glutamate oxaloacetate transaminase 1) and Gs2 (Glutamine synthetase 2). We focused on these by employing available mutants and observed that variants of these genes also showed high levels of LL rhythmicity compared with controls. It was also clear that the genetic background was important with a strong interaction observed with the common and naturally occurring timeless (tim) polymorphisms, ls-tim and s-tim. The less circadian photosensitive ls-tim allele generated high levels of LL rhythmicity in combination with Got1 or Gs2, even though ls-tim and s-tim alleles do not, by themselves, generate the LL phenotype. The use of dsRNAi for both genes as well as for Gad (Glutamic acid decarboxylase) and the metabotropic glutamate receptor DmGluRA driven by clock gene promoters also revealed high levels of LL rhythmicity compared to controls. It is clear that the glutamate pathway is heavily implicated in circadian photoreception. TIM levels in Got1 and Gs2 mutants cycled and were more abundant than in controls under LL. Got1 but not Gs2 mutants showed diminished phase shifts to 10 min light pulses. Neurogenetic dissection of the LL rhythmic phenotype using the gal4/gal80 UAS bipartite system suggested that the more dorsal CRY-negative clock neurons, DNs and LNds were responsible for the LL phenotype. Immunocytochemistry using the CPTI YFP tagged insertions for the two genes revealed that the DN1s but not the DN2 and DN3s expressed Got1 and Gs2, but expression was also observed in the lateral neurons, the LNds and s-LNvs. Expression of both genes was also found in neuroglia. However, downregulation of glial Gs2 and Got1 using repo-gal4 did not generate high levels of LL rhythmicity, so it is unlikely that this phenotype is mediated by glial expression. Our results suggest a model whereby the DN1s and possibly CRY-negative LNds use glutamate signaling to supress the pacemaker s-LNvs in LL.

A pilot study on assessment of locomotor behavior using a video tracking system in minipigs

Pigs are often selected for large animal models including for neuroscience and behavioral research, because their anatomy and biochemistry are similar to those of humans. However, behavioral assessments, in combination with objective long-term monitoring, is difficult. In this study, we introduced an automated video tracking system which was previously used in rodent studies, for use with pig models. Locomotor behaviors (total distance, number of zone transitions, and velocity) were evaluated and their changes were validated by different 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration methods and dosing regimens. Three minipigs (23-29 kg) received subcutaneous or intravenous MPTP, either 1 or 3 times per week. Immediately after MPTP injection, the minipigs remained in a corner and exhibited reduced trajectory. In addition, the total distance travelled, number of zone transitions, and velocity were greatly reduced at every MPTP administration in all the minipigs, accompanying to increased resting time. However, the MPTP-induced symptoms were reversed when MPTP administration was terminated. In conclusion, this automated video-tracking system was able to monitor long-term locomotor activity and differentiate detailed alterations in large animals. It has the advantages of being easy to use, higher resolution, less effort, and more delicate tracking. Additionally, as our method can be applied to the animals' home pen, no habituation is needed.

Comprehensive Analysis of Neurotoxin-Induced Ablation of Dopaminergic Neurons in Zebrafish Larvae

Neurotoxin exposure of zebrafish larvae has been used to mimic a Parkinson’s disease (PD) phenotype and to facilitate high-throughput drug screening. However, the vulnerability of zebrafish to various neurotoxins was shown to be variable. Here, we provide a direct comparison of ablative effectiveness in order to identify the optimal neurotoxin-mediated dopaminergic (DAnergic) neuronal death in larval zebrafish. Transgenic zebrafish, Tg(dat:eGFP), were exposed to different concentrations of the neurotoxins MPTP, MPP⁺, paraquat, 6-OHDA, and rotenone for four days, starting at three days post-fertilization. The LC₅₀ of each respective neurotoxin concentration was determined. Confocal live imaging on Tg(dat:eGFP) showed that MPTP, MPP⁺, and rotenone caused comparable DAnergic cell loss in the ventral diencephalon (vDC) region while, paraquat and 6-OHDA caused fewer losses of DAnergic cells. These results were further supported by respective gene expression analyses of dat, th, and p53. Importantly, the loss of DAnergic cells from exposure to MPTP, MPP⁺, and rotenone impacted larval locomotor function. MPTP induced the largest motor deficit, but this was accompanied by the most severe morphological impairment. We conclude that, of the tested neurotoxins, MPP⁺ recapitulates a substantial degree of DAnergic ablation and slight locomotor perturbations without systemic defects indicative of a Parkinsonian phenotype.

Abnormalities detected at pre-purchase examination of National Hunt racehorses presented at sale

BACKGROUND

Few studies are available concerning prevalences of abnormalities in the Thoroughbred horse population.

OBJECTIVES

Determine the prevalence of commonly observed abnormalities in a National Hunt Thoroughbred population using results of pre-purchase examinations conducted at Thoroughbred sales venues.

STUDY DESIGN

Retrospective cross-sectional study.

METHODS

Veterinary pre-purchase examination certificates for 13,603 3- and 4-year-old Thoroughbred National Hunt horses from Tattersalls Ireland, Goffs Ireland and Doncaster Bloodstock Sales Ltd. (DBS) Sales were analysed. All conditions noted by the veterinarians were recorded to determine the prevalence of abnormalities.

RESULTS

Abnormalities were recorded in 73.6% of horses; 12.0% had abnormalities likely to prejudice their use for racing. Metacarpal/metatarsal exostoses and tarsal-plantar desmitis affected 17.1 and 19.4% of the sample respectively, while 9.9% were found to make abnormal respiratory noises and 5.3% had recurrent laryngeal neuropathy. Age, year of birth and sex significantly affected the prevalence of many abnormalities (P<0.001). The proportions of horses sold differed significantly between horses with and without some abnormalities, with unaffected horses significantly more likely to be sold (e.g., prejudicial findings present vs. non-prejudicial/none, 38.1% vs. 77.6% respectively, P<0.001). A range of abnormalities significantly negatively affected the price at sale (P<0.001). Significantly higher proportions of horses in the lower price categories had multiple abnormalities (P<0.001).

MAIN LIMITATIONS

The study consisted only of horses entered into store horse sales and presented for sale. Horses kept for racing or breeding purposes or horses withdrawn prior to the panel veterinary pre-purchase examination were not included. The upper respiratory tract was only examined endoscopically in horses found to have an abnormal respiratory noise.

CONCLUSIONS

A large proportion of 3- and 4-year-old Thoroughbred National Hunt horses intended for sale are affected by abnormalities. The prevalence of many abnormalities increases with age and certain abnormalities are viewed negatively by purchasers, affecting sale of the horse and achieved sale price.

Formulation and Evaluation of Neuroactive Drug Loaded Chitosan Nanoparticle for Nose to Brain Delivery: In-vitro Characterization and In-vivo Behavior Study

BACKGROUND

The present work was designed to explore the efficacy of neuroactive drug (risperidone) loaded chitosan lipid nanoparticle (RIS-CH-LNPs) to enhance the bioactivity in schizophrenia via the nasal route.

METHODS

The three-factor and three-level formulation by design approach was used for optimization and their effects were observed on (Y1) size in nm, (Y2) % drug loading, and (Y3) % drug release. The optimized formulation RIS-CH-LNPopt was further evaluated for its surface morphology, ex-vivo permeation study, in-vivo behavior study, and stability study. The developed RIS-CH-LNPs showed nanometric size range with high drug loading and prolonged drug release.

RESULTS

The optimized formulation (RIS-CH-LNPopt) has shown the particle size (132.7 nm), drug loading (7.6 %), drug release (80.7 %) and further ex-vivo permeation study showed 2.32 fold enhancement over RIS-SUS(suspension). In-vivo behavior studies showed that RIS-CH-LNPopt is able to show significant greater bioefficacy as compared to RIS-SUS [intranasal (i.n), intravenous (i.v)]. The pharmacokinetic and brain/plasma ratio of developed chitosan nanoparticle was higher at all time-points as compared to RIS-SUS either given by intranasal or intravenous route that proves the direct nose to brain transport pathway of the drug via nasal administration. The developed chitosan nanoparticle increases nose to brain drug delivery as compared to the dispersion of equivalent dose.

CONCLUSION

The findings of this study substantiate the existence of a direct nose-to-brain delivery route for RIS-CH-LNPs.

Zebrafish Locomotor Responses Reveal Irritant Effects of Fine Particulate Matter Extracts and a Role for TRPA1

Exposure to fine particulate matter (PM) air pollution causes adverse cardiopulmonary outcomes. Yet, the limited capacity to readily identify contributing PM sources and associated PM constituents in any given ambient air shed impedes risk assessment efforts. The health effects of PM have been attributed in part to its capacity to elicit irritant responses. A variety of chemicals trigger irritant behavior responses in zebrafish that can be easily measured. The purposes of this study were to examine the utility of zebrafish locomotor responses in the toxicity assessment of fine PM and its chemical fractions and uncover mechanisms of action. Locomotor responses were recorded in 6-day-old zebrafish exposed for 60 min in the dark at 26 °C to the extractable organic matter of a compressor-generated diesel exhaust PM (C-DEP) and 4 of its fractions (F1-F4) containing varying chemical classes of increasing polarity. The role of the transient receptor potential (TRP) cation channel TRPA1, a chemical sensor in mammals and zebrafish, in locomotor responses to C-DEP, was also examined. Acrolein, an environmental irritant and known activator of TRPA1, and all extracts induced concentration-dependent locomotor responses whose potencies ranked as follows: polar F3 > weakly polar F2 > C-DEP > highly polar F4 > nonpolar F1, indicating that polar and weakly polar fractions that included nitro- and oxy-polyaromatic hydrocarbons (PAHs), drove C-DEP responses. Irritant potencies in fish positively correlated with mutagenic potencies of the same extracts in strains of Salmonella sensitive to nitro- and oxy-PAHs, further implicating these chemical classes in the zebrafish responses to C-DEP. Pharmacologic inhibition of TRPA1 blocked locomotor responses to acrolein and the extracts. Taken together, these data indicate that the zebrafish locomotor assay may help expedite toxicity screening of fine PM sources, identify causal chemical classes, and uncover plausible biological mechanisms.

Differential effects of chronic 17β-oestradiol treatment on rat behaviours relevant to depression

Sex differences are a prominent feature of the pathophysiology of psychiatric disorders, such as major depressive disorder, which affects women at a higher incidence than men. Research suggests that the most potent endogenous oestrogen, 17β-oestradiol, may have therapeutic potential in treating depression. However, preclinical studies have produced mixed results, likely as a result of various methodological factors such as treatment duration. The present study aimed to investigate the effects of ovariectomy and chronic 17β-oestradiol treatment via a s.c. silastic implant on behaviours relevant to depression in adult female Sprague-Dawley rats. Rats were assessed in the forced swim test, saccharin preference test and novel object recognition memory test, as well as for possible confounding behaviours, including locomotion and anxiety (open field test) and motivation and anxiety (novelty suppressed feeding test). Treatment effects were verified using body and uterus weight, as well as serum concentrations of 17β-oestradiol, progesterone and testosterone. Compared to ovariectomised rats, chronic 17β-oestradiol treatment enhanced saccharin preference and novel object recognition performance. There were no group differences in passive or active coping behaviour when assayed using the forced swim test. Taken together, these results support an antidepressant-like action of oestrogens but highlight that the beneficial effects of chronic 17β-oestradiol treatment may be related to specific depression-related symptoms, particularly anhedonia and memory.

MDN brain descending neurons coordinately activate backward and inhibit forward locomotion

Command-like descending neurons can induce many behaviors, such as backward locomotion, escape, feeding, courtship, egg-laying, or grooming (we define ‘command-like neuron’ as a neuron whose activation elicits or ‘commands’ a specific behavior). In most animals, it remains unknown how neural circuits switch between antagonistic behaviors: via top-down activation/inhibition of antagonistic circuits or via reciprocal inhibition between antagonistic circuits. Here, we use genetic screens, intersectional genetics, circuit reconstruction by electron microscopy, and functional optogenetics to identify a bilateral pair of Drosophila larval ‘mooncrawler descending neurons’ (MDNs) with command-like ability to coordinately induce backward locomotion and block forward locomotion; the former by stimulating a backward-active premotor neuron, and the latter by disynaptic inhibition of a forward-specific premotor neuron. In contrast, direct monosynaptic reciprocal inhibition between forward and backward circuits was not observed. Thus, MDNs coordinate a transition between antagonistic larval locomotor behaviors. Interestingly, larval MDNs persist into adulthood, where they can trigger backward walking. Thus, MDNs induce backward locomotion in both limbless and limbed animals.

When we choose to make one kind of movement, it often prevents us making another. We cannot move forward and backward at the same time, for example, and a horse cannot simultaneously gallop and walk. These ‘antagonistic’ behaviors often use the same group of muscles, but the muscles contract in a different order. This requires exquisite control over muscle contractions.

Neurons located in the central nervous system form circuits to produce distinct patterns of muscle contractions and to switch between these patterns. Smooth, rapid switching between behaviors is important for animal escape and survival, as well as for performing fine movements. However, we know little about how the activity of the neuronal circuits enables this.

Carreira-Rosario, Zarin, Clark et al. set out to identify the underlying neuronal circuitry that allows larval fruit flies to transition between crawling forward and backward. Results from a combination of genetics and microscopy techniques revealed that a neuron called the Mooncrawler Descending Neuron (MDN) induces a switch from forward to backward travel. MDN activates a neuron that stops the larvae crawling forward, and at the same time activates a different neuron that is only active when the larvae crawl backward. Carreira-Rosario et al. also found that MDN triggers backward crawling in the six-limbed adult fly.

Understanding how a single neuron – in this case MDN – can trigger a smooth switch between opposing behaviors could be beneficial for the medical and robotics fields. In the medical field, understanding how movement is generated could help to improve therapies that fix damage to the relevant neuronal circuits. Understanding how behavioral transitions occur may also help to design autonomous robots that can navigate complex terrain.

Behavioral and Neural Subsystems of Rodent Exploration

Animals occupy territories in which resources such as food and shelter are often distributed unevenly. While studies of exploratory behavior have typically involved the laboratory rodent as an experimental subject, questions regarding what constitutes exploration have dominated. A recent line of research has utilized a descriptive approach to the study of rodent exploration, which has revealed that this behavior is organized into movement subsystems that can be readily quantified. The movements include home base behavior, which serves as a central point of attraction from which rats and mice organize exploratory trips into the remaining environment. In this review, we describe some of the features of this organized behavior pattern as well as its modulation by sensory cues and previous experience. We conclude the review by summarizing research investigating the neurobiological bases of exploration, which we hope will stimulate renewed interest and research on the neural systems mediating rodent exploratory behavior.

Morphine treatment enhances glutamatergic input onto neurons of the nucleus accumbens via both disinhibitory and stimulating effect

Drug addiction is a chronic brain disorder characterized by the compulsive repeated use of drugs. The reinforcing effect of repeated use of drugs on reward plays an important role in morphine-induced addictive behaviors. The nucleus accumbens (NAc) is an important site where morphine treatment produces its reinforcing effect on reward. However, how morphine treatment produces its reinforcing effect on reward in the NAc remains to be clarified. In the present study, we studied the influence of morphine treatment on the effects of DA and observed whether morphine treatment could directly change glutamatergic synaptic transmission in the NAc. We also explored the functional significance of morphine-induced potentiation of glutamatergic synaptic transmission in the NAc at behavioral level. Our results show that (1) morphine treatment removes the inhibitory effect of DA on glutamatergic input onto NAc neurons; (2) morphine treatment potentiates glutamatergic input onto NAc neurons, especially the one from the basolateral amygdala (BLA) to the NAc; (3) blockade of glutamatergic synaptic transmission in the NAc or ablation of projection neurons from BLA to NAc significantly decreases morphine treatment-induced increase in locomotor activity. These results suggest that morphine treatment enhances glutamatergic input onto neurons of the NAc via both disinhibitory and stimulating effect and therefore increases locomotor activity.

Task-Specific and Functional Effects of Speed-Focused Elliptical or Motor-Assisted Cycle Training in Children With Bilateral Cerebral Palsy: Randomized Clinical Trial

BACKGROUND

Locomotor training using treadmills or robotic devices is commonly utilized to improve gait in cerebral palsy (CP); however, effects are inconsistent and fail to exceed those of equally intense alternatives. Possible limitations of existing devices include fixed nonvariable rhythm and too much limb or body weight assistance.

OBJECTIVE

To quantify and compare effectiveness of a motor-assisted cycle and a novel alternative, an elliptical, in CP to improve interlimb reciprocal coordination through intensive speed-focused leg training.

METHODS

A total of 27 children with bilateral CP, 5 to 17 years old, were randomized to 12 weeks of 20 minutes, 5 days per week home-based training (elliptical = 14; cycle = 13) at a minimum of 40 revolutions per minute, with resistance added when speed target was achieved. Primary outcomes were self-selected and fastest voluntary cadence on the devices and gait speed. Secondary outcomes included knee muscle strength, and selective control and functional mobility measures.

RESULTS

Cadence on trained but not nontrained devices increased, demonstrating task specificity of training and increased exercise capability. Mean gait speed did not increase in either group, nor did parent-reported functional mobility. Knee extensor strength increased in both. An interaction between group and time was seen in selective control with scores slightly increasing for the elliptical and decreasing for the cycle, possibly related to tighter limb coupling with cycling.

CONCLUSIONS

Task-specific effects were similarly positive across groups, but no transfer was seen to gait or function. Training dose was low (≤20 hours) compared with intensive upper-limb training recommendations and may be insufficient to produce appreciable clinical change.

Rapid Alleviation of Parkinson's Disease Symptoms via Electrostimulation of Intrinsic Auricular Muscle Zones

Background: Deep brain stimulation of the subthalamic nucleus (STN-DBS) and the pedunculopontine nucleus (PPN) significantly improve cardinal motor symptoms and postural instability and gait difficulty, respectively, in Parkinson's disease (PD). Objective and Hypothesis: Intrinsic auricular muscle zones (IAMZs) allow the potential to simultaneously stimulate the C2 spinal nerve, the trigeminal nerve, the facial nerve, and sympathetic and parasympathetic nerves in addition to providing muscle feedback and control areas including the STN, the PPN and mesencephalic locomotor regions. Our aim was to observe the clinical responses to IAMZ stimulation in PD patients. Method: Unilateral stimulation of an IAMZ, which includes muscle fibers for proprioception, the facial nerve, and C2, trigeminal and autonomic nerve fibers, at 130 Hz was performed in a placebo- and sham-controlled, double-blinded, within design, two-armed study of 24 PD patients. Results: The results of the first arm (10 patients) of the present study demonstrated a substantial improvement in Unified Parkinson's Disease Ratings Scale (UPDRS) motor scores due to 10 min of IAMZ electrostimulation (p = 0.0003, power: 0.99) compared to the placebo control (p = 0.130). A moderate to large clinical difference in the improvement in UPDRS motor scores was observed in the IAMZ electrostimulation group. The results of the second arm (14 patients) demonstrated significant improvements with dry needling (p = 0.011) and electrostimulation of the IAMZ (p < 0.001) but not with sham electrostimulation (p = 0.748). In addition, there was a significantly greater improvement in UPDRS motor scores in the IAMZ electrostimulation group compared to the IAMZ dry needling group (p < 0.001) and the sham electrostimulation (p < 0.001) groups. The improvement in UPDRS motor scores of the IAMZ electrostimulation group (ΔUPDRS = 5.29) reached moderate to high clinical significance, which was not the case for the dry needling group (ΔUPDRS = 1.54). In addition, both arms of the study demonstrated bilateral improvements in motor symptoms in response to unilateral IAMZ electrostimulation. Conclusion: The present study is the first demonstration of a potential role of IAMZ electrical stimulation in improving the clinical motor symptoms of PD patients in the short term.

Anorexic response to rapamycin does not appear to involve a central mechanism

The authors have previously demonstrated that a low and intermittent peripheral dose of rapamycin (1 mg/kg three times/week) to rats inhibited mTORC1 signalling, but avoided the hyperlipidemia and diabetes-like syndrome associated with higher doses of rapamycin. The dosing regimen reduced food intake, body weight, adiposity, serum leptin and triglycerides. mTORC1 signalling was inhibited in both liver and hypothalamus, suggesting some of the actions, in particular the decrease in food intake, may be the results of a central mechanism. To test this hypothesis, rapamycin (30 μg/day for 4 weeks) was infused into 23-25-month-old F344xBN rats by intracerebroventricular (icv) mini pumps. Our results demonstrated that central infusion did not alter food intake or body weight, although there was a tendency for a decrease in body weight towards the end of the study. mTORC1 signalling, evidenced by decreased phosphorylation of S6 protein at end of 4 weeks, was not activated in liver, hypothalamus or hindbrain. Fat and lean mass, sum of white adipose tissues, brown adipose tissue, serum glucose, insulin and leptin levels remained unchanged. Thus, these data suggest that the anorexic and body weight responses evident with peripheral rapamycin are not the result of direct central action. The tendency for decreased body weight towards the end of study, suggests that there is either a slow transport of centrally administered rapamycin into the periphery, or that there is delayed action of rapamycin at sites in the brain.

The behavioral and physiological effects of high-fat diet and alcohol consumption: Sex differences in C57BL6/J mice

BACKGROUND AND OBJECTIVE

Animal studies can be a great tool to investigate sex differences in a variety of different ways, including behavioral and physiological responses to drug treatments and different "lifestyle variables" such as diets. Consumption of both high-fat diets and alcohol is known to affect anxiety behaviors and overall health. This project investigated how high-fat diet and alcohol access and its combination affected the behavior and physiology of male and female C57BL/6J mice.

METHOD

Mice were separated into three food groups: high-fat diet, 10% fat diet, and regular chow, and each group was paired with either water or 10% alcohol. Behavioral assays included diet and alcohol preference, light-dark box, open field, and feeding and drinking measurements. Physiological measures included glucose tolerance tests and measurement of brain-derived neurotrophic factor, insulin, and leptin levels.

RESULTS

Females and males differed in the open field, as male mice decreased activity, while females increased activity when consuming high-fat diet. While females consumed more ethanol than males, alcohol consumption was able to improve glucose tolerance and increase anxiety in both sexes. Lastly, females were more resistant to the physiological changes caused by high-fat diet than males, as females consuming high-fat diet exhibited decreased insulin secretion, less change to brain-derived neurotrophic factor levels, and better glucose tolerance than males consuming high-fat diet.

CONCLUSION

These results suggest that the response to high-fat diet and alcohol consumption is sex dependent and that males are more affected both behaviorally and physiologically by high-fat diet compared to females.

Dopamine D3/D2 Receptor Antagonist PF-4363467 Attenuates Opioid Drug-Seeking Behavior without Concomitant D2 Side Effects

Dopamine receptor antagonism is a compelling molecular target for the treatment of a range of psychiatric disorders, including substance use disorders. From our corporate compound file, we identified a structurally unique D3 receptor (D3R) antagonist scaffold, 1. Through a hybrid approach, we merged key pharmacophore elements from 1 and D3 agonist 2 to yield the novel D3R/D2R antagonist PF-4363467 (3). Compound 3 was designed to possess CNS drug-like properties as defined by its CNS MPO desirability score (≥4/6). In addition to good physicochemical properties, 3 exhibited low nanomolar affinity for the D3R (D3 K_i = 3.1 nM), good subtype selectivity over D2R (D2 K_i = 692 nM), and high selectivity for D3R versus other biogenic amine receptors. In vivo, 3 dose-dependently attenuated opioid self-administration and opioid drug-seeking behavior in a rat operant reinstatement model using animals trained to self-administer fentanyl. Further, traditional extrapyramidal symptoms (EPS), adverse side effects arising from D2R antagonism, were not observed despite high D2 receptor occupancy (RO) in rodents, suggesting that compound 3 has a unique in vivo profile. Collectively, our data support further investigation of dual D3R and D2R antagonists for the treatment of drug addiction.

Locomotor analysis identifies early compensatory changes during disease progression and subgroup classification in a mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a motoneuron degenerative disease that is challenging to diagnose and presents with considerable variability in survival. Early identification and enhanced understanding of symptomatic patterns could aid in diagnosis and provide an avenue for monitoring disease progression. Use of the mSOD1G93A mouse model provides control of the confounding environmental factors and genetic heterogeneity seen in amyotrophic lateral sclerosis patients, while investigating underlying disease-induced changes. In the present study, we performed a longitudinal behavioral assessment paradigm and identified an early hindlimb symptom, resembling the common gait abnormality foot drop, along with an accompanying forelimb compensatory mechanism in the mSOD1G93A mouse. Following these initial changes, mSOD1 mice displayed a temporary hindlimb compensatory mechanism resembling an exaggerated steppage gait. As the disease progressed, these compensatory mechanisms were not sufficient to sustain fundamental locomotor parameters and more severe deficits appeared. We next applied these initial findings to investigate the inherent variability in B6SJL mSOD1G93A survival. We identified four behavioral variables that, when combined in a cluster analysis, identified two subpopulations with different disease progression rates: a fast progression group and a slow progression group. This behavioral assessment paradigm, with its analytical approaches, provides a method for monitoring disease progression and detecting mSOD1 subgroups with different disease severities. This affords researchers an opportunity to search for genetic modifiers or other factors that likely enhance or slow disease progression. Such factors are possible therapeutic targets with the potential to slow disease progression and provide insight into the underlying pathology and disease mechanisms.

Loss of ZBTB20 impairs circadian output and leads to unimodal behavioral rhythms

Many animals display morning and evening bimodal activities in the day/night cycle. However, little is known regarding the potential components involved in the regulation of bimodal behavioral rhythms in mammals. Here, we identified that the zinc finger protein gene Zbtb20 plays a crucial role in the regulation of bimodal activities in mice. Depletion of Zbtb20 in nerve system resulted in the loss of early evening activity, but the increase of morning activity. We found that Zbtb20-deficient mice exhibited a pronounced decrease in the expression of Prokr2 and resembled phenotypes of Prok2 and Prokr2-knockout mice. Injection of adeno-associated virus-double-floxed Prokr2 in suprachiasmatic nucleus could partly restore evening activity in Nestin-Cre; Zbtb20^fl/fl (NS-ZB20KO) mice. Furthermore, loss of Zbtb20 in Foxg1 loci, but intact in the suprachiasmatic nucleus, was not responsible for the unimodal activity of NS-ZB20KO mice. Our study provides evidence that ZBTB20-mediated PROKR2 signaling is critical for the evening behavioral rhythms.

DOI:http://dx.doi.org/10.7554/eLife.17171.001

The Transition from Crawling to Walking: Can Infants Elicit an Alteration of Their Parents' Perception?

Our study was designed to address a gap in the literature on parents' perception and motivation to protect their infants from potential risk of injury in the transition from crawling to walking. The participants were 260 Italian subjects, of whom 158 were women and 102 men, aged between 20 and 45 years. They were asked to draw two domestic objects (a kitchen table and a CD cover) to assess the possible alterations in the perception of environmental elements seen by the parents as a potentially dangerous cause of unintentional injury for their child. Analysis showed that the group of mothers with children aged 9-18 months had drawn the largest tables, while the table areas of the other two categories of women were much smaller. As for the males, the group that drew the largest tables was the one with children, but not in the age range of 9-18 months, while there was little difference between the other two groups. The final descriptive analysis concerned the average scores on the STAI-Y tests both for state and trait anxiety. In all groups a substantial parity was observed, except for the non-parent men, who had a lower level of state anxiety. Both the fathers and the mothers of children aged 9-18 months obtained lower scores, both for state and trait anxiety. Based on the findings, we demonstrate that children transitioning from crawling to walking can elicit a perceptive reactivity in their mothers, which satisfies their natural need to protect their offspring.

Initial locomotor sensitivity to cocaine varies widely among inbred mouse strains

Initial sensitivity to psychostimulants can predict subsequent use and abuse in humans. Acute locomotor activation in response to psychostimulants is commonly used as an animal model of initial drug sensitivity and has been shown to have a substantial genetic component. Identifying the specific genetic differences that lead to phenotypic differences in initial drug sensitivity can advance our understanding of the processes that lead to addiction. Phenotyping inbred mouse strain panels are frequently used as a first step for studying the genetic architecture of complex traits. We assessed locomotor activation following a single, acute 20 mg/kg dose of cocaine (COC) in males from 45 inbred mouse strains and observed significant phenotypic variation across strains indicating a substantial genetic component. We also measured levels of COC, the active metabolite, norcocaine and the major inactive metabolite, benzoylecgonine, in plasma and brain in the same set of inbred strains. Pharmacokinetic (PK) and behavioral data were significantly correlated, but at a level that indicates that PK alone does not account for the behavioral differences observed across strains. Phenotypic data from this reference population of inbred strains can be utilized in studies aimed at examining the role of psychostimulant-induced locomotor activation on drug reward and reinforcement and to test theories about addiction processes. Moreover, these data serve as a starting point for identifying genes that alter sensitivity to the locomotor stimulatory effects of COC.

α6-Containing nicotinic acetylcholine receptors in midbrain dopamine neurons are poised to govern dopamine-mediated behaviors and synaptic plasticity

Acetylcholine (ACh) acts through nicotinic and muscarinic ACh receptors in the ventral midbrain and striatal areas to influence dopamine (DA) transmission. This cholinergic control of DA transmission is important for processes such as attention and motivated behavior, and is manipulated by nicotine in tobacco products. Identifying and characterizing the key ACh receptors involved in cholinergic control of DA transmission could lead to small molecule therapeutics for treating disorders involving attention, addiction, Parkinson's disease, and schizophrenia. α6-Containing nicotinic acetylcholine receptors (nAChRs) are highly and specifically expressed in midbrain DA neurons, making them an attractive drug target. Here, we used genetic, pharmacological, behavioral, and biophysical approaches to study this nAChR subtype. For many experiments, we used mice expressing mutant α6 nAChRs ("α6L9S" mice) that increase the sensitivity of these receptors to agonists such as ACh and nicotine. Taking advantage of a simple behavioral phenotype exhibited by α6L9S mice, we compared the ability of full versus partial α6(∗) nAChR agonists to activate α6(∗) nAChRs in vivo. Using local infusions of both agonists and antagonists into the brain, we demonstrate that neurons and nAChRs in the midbrain are sufficient to account for this behavioral response. To complement these behavioral studies, we studied the ability of in vivo α6(∗) nAChR activation to support plasticity changes in midbrain DA neurons that are relevant to behavioral sensitization and addiction. By coupling local infusion of drugs and brain slice patch-clamp electrophysiology, we show that activating α6(∗) nAChRs in midbrain DA areas is sufficient to enhance glutamatergic transmission in ventral tegmental area (VTA) DA neurons. Together, these results from in vivo studies strongly suggest that α6(∗) nAChRs expressed by VTA DA neurons are positioned to strongly influence both DA-mediated behaviors and the induction of synaptic plasticity by nicotine.