Search results for "Dominance-Subordination"
showing 10 items of 12 documents
Indomethacin blocks the increased conditioned rewarding effects of cocaine induced by repeated social defeat
2018
It is well established that repeated social defeat stress can induce negative long-term consequences such as increased anxiety-like behavior and enhances the reinforcing effect of psychostimulants in rodents. In the current study, we evaluated how the immune system may play a role in these long-term effects of stress. A total of 148 OF1 mice were divided into different experimental groups according to stress condition (exploration or social defeat) and pre-treatment (saline, 5 or 10 mg/kg of the anti-inflammatory indomethacin) before each social defeat or exploration episode. Three weeks after the last social defeat, anxiety was evaluated using an elevated plus maze paradigm. After this tes…
Teachers bullied by students: forms of bullying and perpetrator characteristics.
2012
The focus of this study is on the forms in which the bullying of school teachers by students manifests itself, the characteristics of the students who engage in the bullying, and the manner in which the students who engage in bullying behave in their own peer relationships. The data was gathered from primary and lower secondary school teachers by means of an Internet survey. The answers of 70 teachers who had experienced bullying by their students are examined.The teachers had been exposed to different forms of bullying by students. They had typically been bullied by male students. In most cases, the bullying had been perpetrated by an individual student or a small group of students. Accord…
The red tooth hypothesis: A computational model of predator-prey relations, protean escape behavior and sexual reproduction
2009
This paper presents an extension of the Red Queen Hypothesis (hereafter, RQH) that we call the Red Tooth Hypothesis (RTH). This hypothesis suggests that predator-prey relations may play a role in the maintenance of sexual reproduction in many higher animals. RTH is based on an interaction between learning on the part of predators and evolution on the part of prey. We present a simple predator-prey computer simulation that illustrates the effects of this interaction. This simulation suggests that the optimal escape strategy from the prey's standpoint would be to have a small number of highly reflexive, largely innate (and, therefore, very fast) escape patterns, but that would also be unlearn…
Biogenic amine levels, reproduction and social dominance in the queenless ant Streblognathus peetersi
2006
Social harmony often relies on ritualized dominance interactions between society members, particularly in queenless ant societies, where colony members do not have developmentally predetermined castes but have to fight for their status in the reproductive and work hierarchy. In this behavioural plasticity, their social organisation resembles more that of vertebrates than that of the "classic" social insects. The present study investigates the neurochemistry of the queenless ant species, Streblognathus peetersi, to better understand the neural basis of the high behavioural plasticity observed in queenless ants. We report measurements of brain biogenic amines [octopamine, dopamine, serotonin]…
Effects of several degrees of chronic social defeat stress on emotional and spatial memory in CD1 mice
2015
In the present study, the effects of several degrees of CSDS (Chronic Social Defeat Stress) on emotional and spatial memory in mice were evaluated in separate experiments. Male CD1 mice were randomly assigned to four experimental groups (n=10-12) for each experiment: NS (non-stressed), S5, S10 and S20 (5, 10 and 20 sessions of CSDS, respectively). The S groups underwent the corresponding number of agonistic encounters (10min each) over a 20-day period. 24h after the last session of CSDS, mice performed the inhibitory avoidance (Experiment 1) or the Morris water maze test (Experiment 2). In both experiments, animals were also evaluated in the elevated plus maze for 5min to obtain complementa…
Effects of acute social stress on the conditioned place preference induced by MDMA in adolescent and adult mice
2014
Exposure to social defeat stress increases the rewarding effects of psychostimulants in animal models, but its effect on 3,4-methylenedioxymethylamphetamine (MDMA) reward has received little attention. In the present study, we evaluated the influence of social defeat on the rewarding effects of MDMA in adolescent [postnatal day (PND) 29-40] and adult (PND 50-61) male mice using the conditioned place preference paradigm. Experimental mice were exposed to social defeat in an agonistic encounter before each session of conditioning with 1.25 or 10 mg/kg of MDMA. The effects of social defeat on corticosterone levels and the motor or the anxiogenic effects of MDMA were also evaluated. Mice expose…
'Up-regulation of histone acetylation induced by social defeat mediates the conditioned rewarding effects of cocaine
2016
Social defeat (SD) induces a long-lasting increase in the rewarding effects of psychostimulants measured using the self-administration and conditioned place procedures (CPP). However, little is known about the epigenetic changes induced by social stress and about their role in the increased response to the rewarding effects of psychostimulants. Considering that histone acetylation regulates transcriptional activity and contributes to drug-induced behavioral changes, we addressed the hypothesis that SD induces transcriptional changes by histone modifications associated with the acquisition of place conditioning. After a fourth defeat, H3(K9) acetylation was decreased in the hippocampus, whil…
Inhibitory avoidance learning in CD1 mice: Effects of chronic social defeat stress
2015
Chronic social defeat stress (CSDS) is an animal model widely used to determine the neurobiological mechanisms of stress and its associated pathologies. In this study, the effects of CSDS on inhibitory avoidance (IA) were evaluated in post-pubertal and adult male CD1 mice, instead of the C57BL/6J strain used in the CSDS standard protocol. CSDS consisted of daily 5-min (experiments 1 and 2) or 10-min (experiment 3) agonistic encounters on 21 consecutive days. Twenty four hours after the last session of CSDS, all the mice were tested for IA. They were also evaluated in an elevated plus-maze, obtaining complementary measures of locomotor activity and emotionality. In experiments 1 and 2, IA le…
Enhanced habit-based learning and decreased neurogenesis in the adult hippocampus in a murine model of chronic social stress
2009
Abstract Stress can induce preferential engagement of habit learning mediated by the basal ganglia, relative to learning that involves complex spatial associations contributed by the hippocampal formation. We explored in mice the influence that chronic episodes of social stress exert on the selection of cognitive/spatial vs. habit-based learning strategies. Male mice were exposed to repeated episodes of social confrontation and were categorized as dominant, subordinate or undetermined according to quantitative ethologically relevant parameters of aggression. Mice were then trained in a conditional discrimination task in the T-maze in the presence of allocentric cues until five correct choic…
Effects of escitalopram on the regulation of brain-derived neurotrophic factor and nerve growth factor protein levels in a rat model of chronic stres…
2009
Escitalopram (ES-CIT) is a widely used, highly specific antidepressant. Until now there has been very little evidence on how this drug under pathological conditions affects an important feature within the pathophysiology of stress-related disorders such as depression: the endogenous neurotrophins. By using a well-characterized rat model in which chronic stress induces depressive-like behavior, the levels of neurotrophins brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were determined in representative brain regions and serum using a highly sensitive improved fluorometric two-site ELISA system. There was a significant increase of BDNF in the left and right cortices aft…