Na+,K(+)-ATPase activity is reduced in hippocampus of rats submitted to an experimental model of depression: effect of chronic lithium treatment and possible involvement in learning deficits

This study was undertaken to verify the effects of chronic stress and lithium treatments on the hippocampal Na+,K(+)-ATPase activity of rats, as well as to investigate the effects of stress interruption and post-stress lithium treatment on this enzyme activity and on spatial memory. Two experiments were carried out; in the first experiment, adult male Wistar rats were divided into two groups: control and submitted to a chronic variate stress paradigm, and subdivided into treated or not with LiCl. After 40 days of treatment, rats were killed, and Na+,K(+)-ATPase activity was determined. In the second experiment, rats were stressed during 40 days, and their performance was evaluated in the Water Maze task. The stressed group was then subdivided into four groups, with continued or interrupted stress treatment and treated or not with lithium for 30 additional days. After a second evaluation of performance in the Water Maze, rats were killed and Na+,K(+)-ATPase activity was also measured. Results showed an impairment in Na+,K(+)-ATPase activity and in Water Maze performance of chronically stressed rats, which were prevented by lithium treatment and reversed by lithium treatment and by stress interruption. These results suggest that the modulation of Na+,K(+)-ATPase activity may be one of the mechanisms of action of lithium in the treatment of mood disorders.     

Why do we share aggressive online content? Testing a short cycle model

The present study aimed to observe the impacts of aggressive online content exposure and personality on aggressive content sharing, considering the mediating role of positive and negative affects. A total of 302 Brazilians, equally divided into two groups, participated in a social network simulation, being exposed to aggressive (experimental group) or neutral (control group) posts and choosing what they would like to share on this site (among aggressive or nonaggressive material). A factorial MANOVA showed a significant difference for positive and negative affects and aggressive content sharing (Wilks' Λ = 0.936; F[3, 298] = 6.812; p = .001; η² = 0.064). Through structural equation modeling, an explanatory model was also tested, in which this behavior was directly predicted by aggressive online content exposure and suffered indirect effects from openness, conscientiousness, and extroversion, mediated by positive affects (goodness-of-fit index = 0.997, comparative fit-index = 0.998, Tucker-Lewis index = 0.996, SRMR = 0.028, root-mean-square error of approximation = 0.035, CI = 0.003−0.054). It is possible to conclude that the objectives are met, highlighting the contribution to understanding aggressive online behavior through the proximal processes described in the general aggression model.     

Social context shapes cognitive abilities: associative memories are modulated by fight outcome and social isolation in the crab Neohelice granulata

Animal Cognition - Cognitive abilities of an animal can be influenced by distinct social experiences. However, the extent of this modulation has not been addressed in different learning scenarios:...     

Implicit open-mindedness: Evidence for and limits on stereotype malleability

Although stereotypes have traditionally been regarded as stable, research has documented their considerable malleability. One potential source of such malleability is intrusion into the stereotype of other concepts also activated when the stereotype is activated. In three experiments we assessed the extent to which stereotypes were influenced by stereotypic, stereotype-unrelated, or counter-stereotypic traits activated in a completely unrelated context immediately prior to stereotype measurement. Across experiments, priming of stereotype-unrelated traits increased their inclusion in the stereotype, whereas priming of counter-stereotypic traits had no effect in the subsequently assessed stereotype. In Experiment 3 we collected perceived dispersion measures and showed that although priming counter-stereotypic traits had no effect on overall characterization of the target group, it boosted perceptions of the group's variability. We accounted for these results by extending Higgins' (1989) Synapse Model of knowledge accessibility to the stereotype domain.     

Attachment insecurity and strategies for regulation: when emotion triggers attention

Attachment-related strategies are thought to be critical for regulation and processing of emotional information. This study examined biases in selective attention to emotional stimuli as a function of insecure attachment. Participants searched for a single target image preceded by to-be-ignored distracters depicting emotional images varying in valence and arousal. Results revealed that, in general, negative distracters affected accuracy levels, and that the anxious attached participants showed a clear interference of the emotional distracters. In contrast, the avoidant group evinced a higher control on such interference. In addition, arousal ratings to distracter images indicated superior emotional activation only for anxious attached participants. Consistent with the evolutionary-based attachment theory threat-related stimuli prompted priority attentional responses. Present findings are in line with evidence showing the deployment of distinct strategies in insecurely attached individuals for the regulation of attention to emotional information.     

Angiotensin-(1-7)/Mas axis integrity is required for the expression of object recognition memory

It has been shown that the brain has its own intrinsic renin-angiotensin system (RAS) and angiotensin-(1-7) (Ang-(1-7)) is particularly interesting, because it appears to counterbalance most of the Ang II effects. Ang-(1-7) exerts its biological function through activation of the G-protein-coupled receptor Mas. Interestingly, hippocampus is one of the regions with higher expression of Mas. However, the role of Ang-(1-7)/Mas axis in hippocampus-dependent memories is still poorly understood. Here we demonstrated that Mas ablation, as well as the blockade of Mas in the CA1-hippocampus, impaired object recognition memory (ORM). We also demonstrated that the blockade of Ang II receptors AT1, but not AT2, recovers ORM impairment of Mas-deficient mice. Considering that high concentrations of Ang-(1-7) may activate AT1 receptors, nonspecifically, we evaluate the levels of Ang-(1-7) and its main precursors Ang I and Ang II in the hippocampus of Mas-deficient mice. The Ang I and Ang II levels are unaltered in the whole hipocampus of MasKo. However, Ang-(1-7) concentration is increased in the whole hippocampus of MasKo mice, as well as in the CA1 area. Taken together, our findings suggest that the functionality of the Ang-(1-7)/Mas axis is essential for normal ORM processing.     

Time-dependent effects of treadmill exercise on aversive memory and cyclooxygenase pathway function

Exercise induces brain function adaptations and improves learning and memory; however the time window of exercise effects has been poorly investigated. Studies demonstrate an important role for cyclooxygenase-2 (COX-2) pathway function in the mechanisms underlying memory formation. The aim of present work was to investigate the effects of treadmill exercise on aversive memory and COX-2, PGE(2) and E-prostanoid receptors contents in the rat hippocampus at different time points after exercise has ended. Adult male Wistar rats were assigned to non-exercised (sedentary) and exercised (running daily for 20min, for 2weeks) groups. The inhibitory avoidance task was used to assess aversive memory and the COX-2, PGE(2) and E-prostanoid receptors (EP1, EP2, EP3 and EP4) levels were determined 1h, 18h, 3days or 7days after the last training session of treadmill exercise. The step down latency in the inhibitory avoidance, COX-2 and EP4 receptors levels were acutely increased by exercise, with a significant positive correlation between aversive memory performance and COX-2 levels. Increased EP2 content decreased PGE(2) levels were observed 7days after the last running session. The treadmill exercise protocol facilitates inhibitory avoidance memory and induces time-dependent changes on COX-2 pathways function (COX-2, PGE(2) and EP receptors).     

Psychometric Properties of the European Portuguese Adaptation of the Insomnia Catastrophizing Scale (ICS)

Journal of Rational-Emotive & Cognitive-Behavior Therapy - The current study developed the first translation and adaptation of the ICS (Insomnia Catastrophizing Scale) into European Portuguese,...