Using Tinbergen's approach to understand play

Play fighting has been proposed to provide animals with experiences that promote behavioural flexibility, which helps them to successfully navigate their physical and social environments later on in life. However, there is much variation in how closely related species play, indeed, even among different strains of rats aspects of their play differ. Is all this variation adaptive in serving play’s critical developmental role? The integrative approach advocated by Tinbergen, suggests not. Among rat strains, the differences in play are simply byproducts of subtle sensorimotor differences. Irrespective of the form of the play, rats of all strains converge on the same key experiences during play that are useful for promoting the development of the prefrontal cortex. That is, the experiences derived from play, despite variations, leads to the same outcome. The lessons learnt from rats serve as a guide for cross-species comparisons.Natural Sciences and Engineering Research Counci

The development of juvenile-typical patterns of play fighting in juvenile rats does not depend on peer-peer play experience in the peri-weaning period

Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) appliesPlay fighting in rats involves attack and defense of the nape. To protect the nape, rats use a variety of defensive tactics, with different strains having specific preferences. Targeting of the nape is established before weaning and defense matures over the course of the week preceding and the week proceeding weaning. Thus, it is possible that experience from engaging in immature forms of play is needed to consolidate the nape as the playful target and for the development of the juvenile-typical pattern of defense. Two experiments were conducted to evaluate this possibility. For the first experiment, male rats were reared over the week post-weaning in either pairs or alone, and their play tested with unfamiliar partners when juveniles (31-34 days). For the second experiment, during the week preceding weaning, male and female rats were placed into one of three conditions: (1) with the mother and no peers, (2) with same-sex siblings but no mother, or (3) with both the mother and same-sex siblings. The subjects were tested in same-sex, samecondition pairs when juveniles (31-34 days). Rats from all conditions, in both experiments, attacked the nape during play fighting and developed the same juvenile-typical patterns of playful defense. This suggests that the experience of peer-peer play in the peri-weaning period is not necessary for the development of the attack and defense components of juvenile-typical play.Ye

Pinning in the play fighting of rats: a comparative perspective with methodological recommendations

Open access article. Creative Commons Attribution 4.0 International LIcense (CC BY 4.0) appliesDuring play fighting, rats attack and defend the nape of the neck and during the course of this competitive interaction, they may adopt a configuration in which one animal stands over its supine partner (i.e., pin). Because the pin configuration is typically frequent and relatively easy to identify, it has been widely used as a marker to detect the effects of experimental treatments. In the present study, the frequency of pinning during standardized, 10-min trials in three strains of rats, Long Evans hooded (LE), Sprague-Dawley (SD) and wild (WWCPS), was compared. LE and SD had higher rates than WWCPS rats (#/min: 6.5, 5.5, 1.5, respectively). When adjusted for strain differences in the frequency of attacks, SD as well as WWCPS rats had lower rates of pinning compared to LE rats. Both SD and WWCPS rats were less likely to use tactics of defense that promote pinning. Moreover, while the majority of the pins achieved in LE rats arose from the defender actively rolling over onto its back, the majority of pins in WWCPS rats arose because one partner pushed the other onto its back. SD rats were intermediate in this regard. Finally, once they do adopt the pin configuration, SD rats are less likely to remain supine than LE and WWCPS rats. That is, both SD and WWCPS rats have significantly fewer pins than LE rats, but a different combination of factors account for this. These data highlight the need to use a battery of measures for ascertaining the effects of experimental manipulations on play. Some suggested guidelines are provided.Ye

Willingness to pay for an early warning system for infectious diseases

Early warning systems for infectious diseases and foodborne outbreaks are designed with the aim of increasing the health safety of citizens. As a first step to determine whether investing in such a system offers value for money, this study used contingent valuation to estimate people’s willingness to pay for such an early warning system in six European countries. The contingent valuation experiment was conducted through online questionnaires administered in February to March 2018 to cross-sectional, representative samples in the UK, Denmark, Germany, Hungary, Italy, and The Netherlands, yielding a total sample size of 3140. Mean willingness to pay for an early warning system was €21.80 (median €10.00) per household per month. Pooled regression results indicate that willingness to pay increased with household income and risk aversion, while they decreased with age. Overall, our results indicate that approximately 80–90% of people would be willing to pay for an increase in health safety in the form of an early warning system for infectious diseases and food-borne outbreaks. However, our results have to be interpreted in light of the usual drawbacks of willingness to pay experiments

The development of strain typical defensive patterns in the play fighting of laboratory rats

Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) appliesDuring play fighting, rats attack and defend the nape, which if contacted is nuzzled with the snout. While all strains of rats use the same suite of defensive tactics to protect the nape, different strains use some tactics more frequently. This study tests two hypotheses for this strain difference: (1) each strain has a preference for using particular tactics and (2) strain differences in defense are a byproduct of strain differences in patterns of nape attack. Juvenile Long-Evans (LE) and Sprague-Dawley (SD) males, raised in same strain quads from shortly after weaning to the early juvenile period (i.e., 24-31 days), were tested with unfamiliar same-strain and different-strain partners (Experiment 1) and LE and SD males raised in mixed LE-SD quads were tested with both familiar (Experiment 2) and unfamiliar same-strain and different-strain partners. If hypothesis (1) were true, they would maintain strain-typical defense patterns irrespective of the strain of the attacking partner, whereas if hypothesis (2) were true, it would vary with the strain of the attacking partner. Hypothesis (1) was supported in the first experiment; all the rats maintained their strain-typical patterns regardless of the partner’s strain. However, Experiments 2 and 3 supported neither hypothesis, as each animal displayed strain-divergent behavior when playing with partners of either strain. Given that in Experiments 2 and 3, subjects were reared in mixed-strain groups, it is possible that, during the early juvenile period, play fighting experiences shape strain-typical patterns of use of defensive tactics.Ye

An Objective Method to Assess and Recommend Exertion and Exercise Targets for Return to Play Post concussion

Introduction. Concussions are of significant concern for athletic trainers, and there is a critical need to objectively and safely allow an athlete to return to play. In sports the objective is return as safely and soon as possible. Exertion is a consideration regarding progressing an athlete back to play. The ability to exert in cardiovascular and strength and conditioning contexts are two critical steps in most return to play protocols. Being able to make objective recommendations is urgently needed, as trial and error leads to unnecessary risk of eliciting symptoms and/or causing setbacks. Objective. The object of this paper is to present the athletic trainer with data associated with a methodology that can be used to aid in designing a cardiovascular and strength training program post concussion. This objective measure does not rely on subjective patient reports of symptoms and utilizes a reflex based assessment method. Description. The transient exertion related carotid (TERC) murmur is a murmur that is heard at the carotid arteries during exercise. It normally is heard at around a heart rate of 150, but is heard at lower heart rates in patients who have sustained a concussion. Listening for the TERC murmur during a cardiovascular and strength training assessment can be used to provide information to the athletic trainer about safer target heart rates or safer lifting strategies post-concussion. We present data concerning 71 athletes (mean age 20.8 years) who were assessed for cardiovascular conditioning and body weight assessment. With 73% of the cardio assessment subjects, a TERC murmur was detected at a heart rate of 127.2 bpm (± 16 SD). For the strength assessment 42.1% had a TERC murmur. Clinical advantages. The clinical advantage of the TERC murmur is that it can be utilized by any athletic trainer trained to take a blood pressure. It provides objective information concerning safe target heart rates that will allow an athletic trainer to recommend appropriate exercise prescriptions. The TERC murmur assessment can also be used to help guide strength training protocols to facilitate safe return. Being able to safely recommend a means by which an athlete can recommence their training (cardiovascular and/or strength training) may accelerate return to play as well as aid in keeping the athlete happy, healthy and engaged

Indonesian Throughflow drove Australian climate form humid Pliocene to arid Pleistocene

Late Miocene to mid-Pleistocene sedimentary proxy records reveal that northwest Australia underwent an abrupt transition from dry to humid climate conditions at 5.5 million years (Ma), likely receiving year-round rainfall, but after ~3.3 Ma, climate shifted toward an increasingly seasonal precipitation regime. The progressive constriction of the Indonesian Throughflow likely decreased continental humidity and transferred control of northwest Australian climate from the Pacific to the Indian Ocean, leading to drier conditions punctuated by monsoonal precipitation. The northwest dust pathway and fully established seasonal and orbitally controlled precipitation were in place by ~2.4 Ma, well after the intensification of Northern Hemisphere glaciation. The transition from humid to arid conditions was driven by changes in Pacific and Indian Ocean circulation and regional atmospheric moisture transport, influenced by the emerging Maritime Continent. We conclude that the Maritime Continent is the switchboard modulating teleconnections between tropical and high-latitude climate systems.published_or_final_versio