Social Stress Alters Inhibitory Synaptic Input to Distinct Subpopulations of Raphe Serotonin Neurons

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Retrieval of contextual memories increases activity-regulated cytoskeleton-associated protein in the amygdala and hippocampus

Activity-regulated cytoskeleton-associated protein (Arc) integrates information from multiple intracellular signaling cascades and, in turn, regulates cytoskeletal proteins involved in structural synaptic modifications. The purposes of the present study were: (1) to determine if the retrieval of contextual memories would induce Arc in hippocampal and amygdalar neurons; (2) use unbiased stereology at the ultrastructural level to quantify synapses contacting Arc-labeled (Arc+) and unlabeled (Arc?) postsynaptic structures in brain regions in which the amount of Arc integrated density (ID) correlated strongly with the degree of amphetamine conditioned place preference (AMPH CPP). The retrieval of contextual memories increased the Arc ID in the dentate gyrus, cornu ammonis (CA)1, and CA3 fields of the hippocampus and the basolateral, lateral, and central nuclei of the amygdala but not the primary auditory cortex, a control region. Stereological quantification of Arc+ and Arc? synapses in the basolateral nucleus of the amygdala (BLA) was undertaken because the strongest relationship between the amount of Arc ID and AMPH CPP was observed in the BLA. The retrieval of contextual memories increased the number and density of asymmetric (presumed excitatory) synapses contacting Arc+ spines and dendrites of BLA neurons, symmetric (presumed inhibitory or modulatory) synapses contacting Arc+ dendrites of BLA neurons, and multisynaptic boutons contacting Arc+ postsynaptic structures. Thus, the retrieval of contextual memories increases Arc in the amygdala and hippocampus, an effect that could be important for approach behavior to a drug-associated context.     

A profile of the Youth Olympic Taekwondo Athlete

Our study aims to identify trends in anthropomorphic attributes and competitive strategies of successful (medalists) versus non medalist young Olympic Taekwondo competitors by gender in terms of body mass, body-mass index (BMI) and fighting technique at the Youth Olympic Games 2010. Results were then compared to adult Taekwondo Olympic athletes in 2000, 2004 and 2008. Data on 96 Taekwondo athletes were obtained from the official Youth Olympic website. A LOGIT analysis was performed on the following six independent variables: height, body mass, body mass index, gender, techniques used to score, and warnings obtained during a match. The study did find some differences between winners and non-winners for males and female, although none of the differences were statistically significant. Consequently, training personnel may enhance winning potential of Taekwondo competitors by focusing on offensive versus defensive techniques and improving the quality of punching.