Experimental tests to assess emotionality in horses

Different tests were used to assess different aspects of the emotionality of 1–3 year-old horses: arena test; a `novel object' test; and a handling test. In reaction to the test situations no important differences were observed according to age or sex in the behaviour patterns, but clear individual differences were observed within these classes. The arena test seemed to reveal the degree of gregariousness of the animals whereas the results in the two other tests were correlated and seemed to reflect an inherent degree of fearfulness in the horse. Indices were developed that enabled to rank the animals, by taking into account all behaviour patterns shown. Such individual characteristics might have some genetic basis: half-siblings tended to behave the same way in most cases.     

Biochemical polymorphism in relation to performance in horses

Summary Investigations on relationships between biochemical polymorphism and variation in quantitative traits are of interest from the perspectives of both theoretical quantitative genetics and practical animal breeding. This subject was studied by using racing performance records of more than 25,000 horses of the Swedish Trotter breed born in the period 1970–1979. For all horses data on six blood group and nine electrophoretic loci were available. Two different performance traits were investigated. A racing performance index value was calculated for all individuals which had started in at least five races. Horses which had not started at all or less than five times were pooled in an unstarted class and the proportion of started horses was analysed as an all-or-none trait. The relationships between the marker genes and these two performance traits were analysed statistically by using linear models. Analysis within sires revealed a very highly significant association between variation at the serum esterase locus (Es) and the proportion of started horses. In addition, four weakly significant associations were found. A striking feature of the highly significant association involving the esterase locus was that the effect of different alleles showed a good fit to an additive genetic model as the value of each heterozygous type was intermediate to the two corresponding homozygotes. In addition to the association tests, the possibility of genetic linkage between marker genes and genes affecting performance was tested as well as the influence on performance of heterozygosity at marker loci. No significant relationships were revealed in these latter tests.     

Comparison of two different actigraphs with polysomnography in healthy young subjects

The present study aimed to compare two commercially available actigraphs, with a concurrent polysomnographic (PSG) recording. Twelve healthy volunteers (six women; age range 19-28 yrs) simultaneously wore the Basic Mini-Motionlogger^® and Actiwatch^® for seven overnight polysomnographic recordings. Comparisons of the following sleep measures were focused on: sleep onset latency (SOL), total sleep time, wake after sleep onset, and sleep efficiency. Both devices underestimated SOL in comparison to PSG, but they had similar performance compared to PSG for the other sleep measures. A limit of the study is that the results can be only generalized to healthy young subjects.     

Effects of penitrem A on rat's performances in passive avoidance and Morris water maze tests

Intraperitoneal administration of the mycotoxin penitrem A 30 min before a training session in passive avoidance task, impaired performance of rats subjected to a test-session 24 h after. This effect was not antagonised by pretraining administration of physostigmine or bicuculline. Administration of penitrem A 20 min before a training session or 30 min before a test-session did not impair performance. In the Morris water maze, doses of penitrem A that induces slight to moderate tremors, but not a lower dose, disrupted place learning. These results suggest that penitrem A disrupts the processes that take place at the time of acquisition, but not those just after acquisition, and does not alter the restitution of information. This effect would not be related to a decrease of cholinergic neurotransmission nor to a stimulation of GABA A receptors. Nevertheless, it could not be totally excluded that the performance impairments induced by penitrem A would be secondary to a motor disruption. This revised version was published online in June 2006 with corrections to the Cover Date.     

Altered Cholinergic Metabolism in Rat CNS Following Aluminum Exposure: Implications on Learning Performance

Abstract: The effects of Al on the central cholinergic system have been studied. Al, at a dose of 10 mg/kg of body weight/day for 4 weeks, had a deleterious effect on the activities of biosynthetic (choline acetyltransferase) and hydrolytic (acetylcholinesterase) enzymes of the neurotransmitter acetylcholine. The levels of acetylcholine were also significantly lowered in different brain regions at the end of the dose regimen. There was a significant decrease in high-affinity choline uptake following Al exposure. Muscarinic acetylcholine receptor binding studies revealed a decreased number of binding sites ( B _max), with the maximum effects being manifested in the hippocampus. Exogenous addition of 10 µ M desferrioxamine restored the muscarinic receptor binding completely. The impaired cholinergic functioning had severe effects on cognitive functions. Neurobehavioral deficits were manifested in terms of decreased active (52%) and passive (73.30%) avoidance tests. The results suggest that Al exerts its toxic effects by altering cholinergic transmission, which is ultimately reflected in neurobehavioral deficits.     

Characterisation of IgG(T) serum antibody responses to two larval antigen complexes in horses naturally- or experimentally-infected with cyathostomins

Cyathostomins are the most common parasitic nematodes of horses. Larval stages, which inhabit the intestinal wall, are particularly pathogenic and can cause severe colitis and colic. Despite their clinical importance, diagnostic techniques for the prepatent stages do not exist. A method that could estimate mucosal infection intensity would have a major impact on the control and diagnosis of cyathostominosis. Here, serum IgG(T) responses to two larval antigen complexes of 25 and 20 kDa were quantified in horses with experimental infections, natural infections and in horses that presented with clinical larval cyathostominosis. In experimentally-infected animals, anti-25 kDa complex IgG(T) levels correlated positively with field exposure and with early third stage larval (r(s)=0.74, P=0.015) and total mucosal parasite (r(s)=0.78, P=0.010) burdens. In naturally exposed horses whose parasite burdens were quantified upon post-mortem examination, antigen-specific IgG(T) responses were significantly higher in infected than in uninfected horses (P=0.0001 and 0.002, for anti-25 and anti-20 kDa responses, respectively). In these animals, anti-25 kDa IgG(T) levels correlated positively with mucosal and lumenal burdens (P<0.05). IgG(T) responses to the 20 kDa antigen complex correlated positively with lumenal burdens (P=0.0043). In cases of larval cyathostominosis, antigen-specific IgG(T) levels were significantly higher than in uninfected ponies (P=0.002 and 0.0035, for anti-25 and anti-20 kDa responses, respectively). These results provide evidence that these two complexes contain antigens with potential as markers for prepatent cyathostomin infection.     

Using eye temperature and heart rate for stress assessment in young horses competing in jumping competitions and its possible influence on sport performance

The aims of this study were, first, to evaluate eye temperature (ET) with infrared thermography and heart rate (HR) to measure stress in horses during show jumping competitions and their relationship with competition results, and second, to evaluate the influence of different extrinsic and intrinsic factors of the horse on the stress measurements analysed. One hundred and seventy-three Spanish Sport Horses were analysed for ET and HR, and these measurements were taken 3 h before the competition, just after and 3 h after it. Two interval measurements were also assessed for each parameter. Positive significant correlations were found between ET and HR, measured before (r=0.23), just after competition (r=0.28) and for the later interval (r=0.26), whereas negative correlations with competition results were found only for ET when measured just after competing (r=−0.25). Two intrinsic factors (genetic line and age) and no extrinsic factors showed significant differences for ET, whereas one intrinsic factor (age) and two extrinsic factors (journey duration and number of training hours) showed significant differences for HR. The marginal means showed significantly higher ET values for the Anglo-Arab genetic line and for 5-year-old animals. HR values were significantly higher for 4-year-old animals, for horses which had travelled 4 to 6 h and for horses that had 3 to 6 h of daily training. This study suggests that, although ET and HR seemed to share a similar physiological basis, the factors that most influenced each parameter were different. Finally, ET seems to be a suitable tool for assessing stress during show jumping competitions in horses.     

Genetic variation in competition traits at different ages and time periods and correlations with traits at field tests of 4-year-old Swedish Warmblood horses

For many years, the breeding value estimation for Swedish riding horses has been based on results from Riding Horse Quality Tests (RHQTs) of 4-year-olds only. Traits tested are conformation, gaits and jumping ability. An integrated index including competition results is under development to both get as reliable proofs as possible and increases the credibility of the indexes among breeders, trainers and riders. The objectives of this study were to investigate the suitability of competition data for use in genetic evaluations of horses and to examine how well young horse performance agrees with performance later in life. Competition results in dressage and show jumping for almost 40 000 horses from the beginning of the 1960s until 2006 were available. For RHQT data of 14 000 horses judged between 1988 and 2007 were used. Genetic parameters were estimated for accumulated competition results defined for different age groups (4 to 6 years of age, 4 to 9 years of age and lifetime), and for different birth year groups. Genetic correlations were estimated between results at RHQT and competitions with a multi-trait animal model. Heritabilities were higher for show jumping than dressage and increased with increasing age of the horse and amount of information. For dressage, heritabilities increased from 0.11 for the youngest group to 0.16 for lifetime results. For show jumping corresponding values increased from 0.24 to 0.28. Genetic correlations between competition results for the different age groups were highly positive (0.84 to 1.00), as were those between jumping traits at RHQT and competition results in show jumping (0.87 to 0.89). For dressage-related traits as 4-year-old and dressage competition results the estimated genetic correlations were between 0.47 and 0.77. We suggest that lifetime results from competitions should be integrated into the genetic evaluation system. However, genetic parameters showed that traits had changed during the over 35-year period covered due to the development of the sport, which needs to be considered in future genetic evaluations.     

Effect of prenatal different auditory environment on learning ability and fearfulness in chicks

ObjectiveEarly environmental enrichment in life can improve cognition in animals. The effect of prenatal auditory stimulation on learning ability and fear level in chick embryos remained unexplored. Therefore, this study investigated the effect of prenatal auditory stimulation on the learning ability and fear level of chicks.MethodsA total of 450 fertilized eggs were randomly divided into 5 groups, including control group (C), low-sound intensity music group (LM), low-sound intensity noise group (LN), high-sound intensity noise group (HN) and high-sound intensity music group (HM). From the 10th day of embryonic development until hatching, group LM and group LN received 65 to 75 dB of music and noise stimulation. Group HN and group HM received 85 to 95 dB of noise and music stimulation, and group C received no additional sound. At the end of incubation, the one-trial passive avoidance learning (PAL) task and tonic immobility (TI) tests were carried out, and the serum corticosterone (CORT) and serotonin (5-HT) concentrations were determined.ResultsThe results showed that compared with the group C, 65 to 75 dB of music and noise stimulation did not affect the PAL avoidance rate (p>0.05), duration of TI (p>0.05) and the concentration of CORT (p>0.05) and 5-HT (p>0.05) in chicks. However, 85 to 95 dB of music and noise stimulation could reduce duration of TI (p<0.05) and the concentration of CORT (p<0.05), but no significant effect was observed on the concentration of 5-HT (p>0.05) and PAL avoidance rate (p>0.05).ConclusionTherefore, the prenatal auditory stimulation of 85 to 95 dB can effectively reduce the fear level of chicks while it does not affect the learning ability.     

Learning of oscillatory correlated patterns in a cortical network by a STDP-based learning rule

In this paper, we propose an iterative learning rule that allows the imprinting of correlated oscillatory patterns in a model of the hippocampus able to work as an associative memory for oscillatory spatio-temporal patterns. We analyze the dynamics in the Fourier domain, showing how the network selectively amplify or distort the Fourier components of the input, in a manner which depends on the imprinted patterns. We also prove that the proposed iterative local rule converges to the pseudo-inverse rule generalized to oscillatory patterns.     

Hebbian errors in learning: An analysis using the Oja model

Background: Recent work on long term potentiation in brain slices shows that Hebb's rule is not completely synapse-specific, probably due to intersynapse diffusion of calcium or other factors. We previously suggested that such errors in Hebbian learning might be analogous to mutations in evolution.Methods and findings: We examine this proposal quantitatively, extending the classical Oja unsupervised model of learning by a single linear neuron to include Hebbian inspecificity. We introduce an error matrix E, which expresses possible crosstalk between updating at different connections. When there is no inspecificity, this gives the classical result of convergence to the first principal component of the input distribution (PC1). We show the modified algorithm converges to the leading eigenvector of the matrix EC, where C is the input covariance matrix. In the most biologically plausible case when there are no intrinsically privileged connections, E has diagonal elements Q and off-diagonal elements (1-Q)/(n-1), where Q, the quality, is expected to decrease with the number of inputs n and with a synaptic parameter b that reflects synapse density, calcium diffusion, etc. We study the dependence of the learning accuracy on b, n and the amount of input activity or correlation (analytically and computationally). We find that accuracy increases (learning becomes gradually less useful) with increases in b, particularly for intermediate (i.e., biologically realistic) correlation strength, although some useful learning always occurs up to the trivial limit Q=1/n.Conclusions and significance: We discuss the relation of our results to Hebbian unsupervised learning in the brain. When the mechanism lacks specificity, the network fails to learn the expected, and typically most useful, result, especially when the input correlation is weak. Hebbian crosstalk would reflect the very high density of synapses along dendrites, and inevitably degrades learning.     

中华倒刺鲃不同生理性能对降温的响应速率

为了考查长期高温驯化的中华倒刺鲃(Spinibarbus sinensis)幼鱼快速降温后不同生理功能对低温环境的响应速率,将实验鱼分为2组分别在15℃和25℃条件下长期驯养(8周),随后25℃组快速降温至15℃(降温组),同时15℃组(恒低温对照组)温度保持不变;在降温后的第1、2、4和8周分别测定和比较降温组和恒温对照组实验鱼的温度耐受能力、游泳能力、自发活动水平、摄食代谢和生长性能等相关生理指标。结果显示:降温后,低温耐受能力(CT_(min))1周时就达到稳定与对照组不再有差异,而高温耐受能力(CT_(max))2周时才达到稳定;与对照组相比,降温处理导致实验鱼自发活动水平(运动时间百分比,PTM和运动总距离,TDM)显著上升,且此差异持续整个驯化周期(P0.05);降温组的临界游泳速度(Critical swimming speed U_(crit))在降温的1—2周均显著小于对照组(P0.05),直到4周才达到稳定;降温组实验鱼特殊动力作用(Specific dynamic action SDA)持续时间和摄食后代谢峰值(Peak metabolic rate PMR)与对照组在降温1—4周均没有显著差异;尽管降温组有更高的摄食率,其食物转化效率和增重率均显著低于对照组(P0.05)。研究表明:中华倒刺鲃在水体温度下降后,不同生理功能的稳定速率存在差异,这可能与不同生理功能的生态关联及内在机制的不同有关;降温处理导致机体生长受阻,其主要原因可能是由于应对环境温度变动的逆境胁迫、生理功能调整以及自发活动增加所导致的能量消耗上升所致。     

Intra-striatal estradiol in female rats impairs response learning within two hours of treatment

Estradiol treatment administered systemically or directly to the dorsolateral striatum across two days impairs performance on a response task in which rats learn to make a specific body turn to locate food on a maze. Estradiol can act through both slow and rapid signaling pathways to regulate learning impairments, however it is impossible to dissociate the slow from the rapid contributions of estradiol following long exposures. To assess the rapid effects of estradiol on striatum-sensitive learning, we trained rats on a response learning task after either relatively short or long treatments of estradiol infused directly into the striatum. Three-month-old female rats were ovariectomized 21 days before training and received guide cannulae implanted bilaterally into the dorsolateral striatum. For short duration treatments, rats were given bilateral infusions (0.5 μl) of 17β-estradiol-sulfate (0, 5, 50, or 500 nM in aCSF-vehicle) either 2 h or 15 min prior to training. For long duration treatments, rats received a series of estradiol infusions (500 nM) at 48, 24, and 2 h prior to training. Replicating previous findings (Zurkovsky et al., 2007), intra-striatal estradiol treatments given for two days prior to training impaired response learning. Estradiol-induced impairments in performance were also demonstrated 2 h, but not 15 min, after single infusions. Thus, estradiol acts within hours of exposure in the striatum, a structure lacking classical estrogen receptors, to impair response learning.     

Preliminary results in using Deep Learning to emulate BLOB,a nuclear interaction model

PurposeA reliable model to simulate nuclear interactions is fundamental for Ion-therapy. We already showed how BLOB (“Boltzmann-Langevin One Body”), a model developed to simulate heavy ion interactions up to few hundreds of MeV/u, could simulate also ¹²C reactions in the same energy domain. However, its computation time is too long for any medical application. For this reason we present the possibility of emulating it with a Deep Learning algorithm.MethodsThe BLOB final state is a Probability Density Function (PDF) of finding a nucleon in a position of the phase space. We discretised this PDF and trained a Variational Auto-Encoder (VAE) to reproduce such a discrete PDF. As a proof of concept, we developed and trained a VAE to emulate BLOB in simulating the interactions of ¹²C with ¹²C at 62 MeV/u. To have more control on the generation, we forced the VAE latent space to be organised with respect to the impact parameter (b) training a classifier of b jointly with the VAE.ResultsThe distributions obtained from the VAE are similar to the input ones and the computation time needed to use the VAE as a generator is negligible.ConclusionsWe show that it is possible to use a Deep Learning approach to emulate a model developed to simulate nuclear reactions in the energy range of interest for Ion-therapy. We foresee the implementation of the generation part in C++ and to interface it with the most used Monte Carlo toolkit: Geant4.     

A neural circuit model of emotional learning using two pathways with different granularity and speed of information processing

We propose a neural circuit model of emotional learning using two pathways with different granularity and speed of information processing. In order to derive a precise time process, we utilized a spiking model neuron proposed by Izhikevich and spike-timing-dependent synaptic plasticity (STDP) of both excitatory and inhibitory synapses. We conducted computer simulations to evaluate the proposed model. We demonstrate some aspects of emotional learning from the perspective of the time process. The agreement of the results with the previous behavioral experiments suggests that the structure and learning process of the proposed model are appropriate.     

Level of anxiety and results of psychomotor tests in young soccer players of different performance levels

The aim of the current study is to determine how the level of state and trait anxiety differs between youth athletes of different performance levels and furthermore whether there are correlations between performance levels and psychomotor variables in the selected tasks. A sample of 97 boys, aged 11–12 years, practising soccer represented two groups: A – high performance level and B – lower performance level. Participants completed a state and trait anxiety inventory and performed selected psychomotor tests. The analyses demonstrated that the higher the levels of anxiety were, the shorter was the response time and more accurate were the responses in selected psychomotor tests. For the whole group, r = -0.224, p < 0.05, and for group B, r = -0.333, p < 0.05. Moreover, the findings showed a moderator effect of level (group A vs B) on reaction time, which was almost significant in state anxiety and significant in trait anxiety. For group B, trait anxiety was negatively related to reaction time (b = -0.002, SE = 0.001, t = -2.93, p = .004, 95% CI [-0.004, -0.001]). This means that the higher the trait anxiety was, the shorter was the reaction time in group B, but there was no significant effect in group A. The results of the study confirmed the negative correlation between the trait and state anxiety and reaction time. The higher the anxiety was, the shorter was the response time of child soccer players. Future research should determine whether athletes’ performance levels do affect performance under stress and replicate the study with different samples such as girls and different sport disciplines.     

Activity profiling of ectomycorrhiza communities in two forest soils using multiple enzymatic tests

Data on the diversity and distribution of enzyme activities in native ectomycorrhizal (ECM) communities are inadequate. A microplate multiple enzymatic test was developed which makes it possible to measure eight enzyme activities on 14 individual, excised ECM root tips. Hydrolytic and oxidative enzymes are involved in the decomposition of lignocellulose, chitin and phosphorus-containing organic compounds. This test system was used to describe the functional diversity of ECM communities in two forest sites. This set of tests proved to be accurate and sensitive enough to reveal a high diversity of activity profiles, depending on the fungal symbiont and the soil horizon. Ectomycorrhizas can be classified into specialists and generalists, and appear to complement each other in the same horizon to collectively perform all eight activities studied. By including a higher number of different assays for more detailed analyses, ECM activity profiling will provide a valuable tool for studying the functional diversity of ECM communities.     

Memory retention capacity using two different training methods,appetitive and aversive learning,in juvenile red sea bream Chrysophrys major

Memory retention based on appetitive and aversive learning was studied in juvenile red sea bream Chrysophrys major. The fish were individually trained via appetitive and aversive learning. In general, they retained appetitive memories for 30 days, but not for 60 days. Conversely, aversive memory endured for 1 day, but not for 3 days or longer. Analyses at the individual level revealed that some fish retained appetitive memories for 60 days, whereas others lost it within 3 days; this suggests considerable variability in memory retention capacity among individual fish. The memory duration for aversive learning was remarkably short, which should be considered when releasing trained fish into the wild for stock enhancement. Furthermore, the high inter-individual variability suggests that evaluating memory retention capacity through group experiments might lead to overestimation of fishes’ ability.     

Aggression in young men high in threat potential increases after hearing low-pitched male voices: two tests of the retaliation-cost model

Research suggests that male voice pitch is an honest dominance signal because it indexes men's physicality and because lower-pitched voices are more costly to develop and maintain. Rather than considering these signaler-dependent mechanisms, we tested a receiver-dependent mechanism hypothesized by M. Enquist's (1985) retaliation-cost model of aggressive signaling. The model predicts that, given a competitive scenario, low-pitched male voices will elicit aggression from male listeners (i.e., signal receivers) who are relatively high in threat potential. We confirmed this hypothesis in two experiments. Under a sexual but not control prime and after listening to low- but not average-pitched male voices, increases in heterosexual male participants' trait dominance predicted stronger aggressive cognitions (Experiment 1), and increases in male participants' handgrip strength predicted stronger aggressive intent (Experiment 2). These findings provide the first direct support for the retaliation-cost model in humans, extend research on the effects of male voice pitch on receiver psychology, and demonstrate an additional cost mechanism that explains why voice pitch is an honest signal of dominance in men.