Animal model of posterior cingulate cortex hypometabolism implicated in amnestic MCI and AD

The posterior cingulate cortex (PCC) is the brain region displaying the earliest sign of energy hypometabolism in patients with amnestic mild cognitive impairment (MCI) who develop Alzheimer’s disease (AD). In particular, the activity of the mitochondrial respiratory enzyme cytochrome oxidase (C.O.) is selectively inhibited within the PCC in AD. The present study is the first experimental analysis designed to model in animals the localized cortical C.O. inhibition found as the earliest metabolic sign of early-stage AD in human neuroimaging studies. Rats were used to model local inhibition of C.O. by direct injection of the C.O. inhibitor sodium azide into the PCC. Learning and memory were examined in a spatial holeboard task and brains were analyzed using quantitative histochemical, morphological and biochemical techniques. Behavioral results showed that sodium azide-treated rats were impaired in their memory of the baited pattern in probe trials as compared to their training scores before treatment, without non-specific behavioral differences. Brain analyses showed that C.O. inhibition was specific to the PCC, and sodium azide increased lipid peroxidation, gliosis and neuron loss, and lead to a network functional disconnection between the PCC and interconnected hippocampal regions. It was concluded that impaired memory by local C.O. inhibition in the PCC may serve to model in animals a metabolic lesion similar to that found in patients with amnestic MCI and early-stage AD. This model may be useful as an in vivo testing platform to investigate neuroprotective strategies to prevent or reduce the amnestic effects produced by posterior cingulate energy hypometabolism.     

Effects of extinction in multiple contexts on the renewal of associative tolerance to ethanol

The Pavlovian analysis of drug tolerance describes how the contexts of drug administration participate in the elicitation of compensatory conditioned responses that are, at least partly, responsible for tolerance. Findings indicate that if an association is acquired in one context and extinguished in another one, when exposing the subjects to the acquisition context, renewal of the conditioned response will take place. Ambiguous evidence exists about whether or not this effect diminishes when extinguishing the association in multiple contexts. This investigation evaluates the existence of the phenomenon of renewal of tolerance to ethanol, and whether it diminishes by the extinction in multiple contexts. Evidence of renewal of tolerance to ethanol in rats was found, but no diminution was observed when extinguishing in multiple contexts.     

Is it advisable to include negative attributes to assess the stereotype content? Yes,but only in the morality dimension

Competence, morality and sociability dimensions have shown to be essential to measure stereotypes. Theoretically, the attributes associated with the negative pole of morality are more reliable and have shown to have higher evaluative weight. However, the current research usually employs only positive attributes to measure each dimension. Since the advantages of the inclusion of negative morality are clear it would be interesting to know about the effects of the inclusion of such type of attributes (i.e., it is good or bad for the measurement). The purpose of this study is to examine if the addition of negative items makes possible to improve the stereotype content measures. This study compares the differences between scales with various compositions of positive and negative items of stereotypes to predict three related variables: anger, fear and a semantic differential of evaluation. The study was carried out with a sample of 550 Spaniards. The data found highlights the importance of using attributes of the negative pole of morality in studying stereotypes. Their use was able to explain the intergroup emotional responses and the semantic differential more efficiently.     

Prejudiced attitude measurement using the Rasch Rating Scale model

There have been two basic approaches for the study of minority group prejudice against the majority: to adapt instruments from the majority group, and to use qualitative techniques by analyzing the content of the discourse of the groups involved. Neither of these procedures solves the problem of measuring intergroup attitudes of majorities and minorities in interaction. This study shows the result of a prejudice scale which was developed to measure the attitude of both the minority and majority groups. Prejudice is conceived as an attitude which requires the beliefs or opinions about the out-group, the emotions it elicits, and the behavior or intentional behavior toward it to be known for its evaluation. The innovation in this work is that the psychometric development of the scale was based on the item response theory, and more specifically, the rating scale model.     

Explicit memory for unattended words: the importance of being in the "no"

Recognition tests in which participants indicate whether they recognize items using binary yes/no response options have typically yielded "yes" responses at equal rates for unattended old items and new items. Because most responses to unattended stimuli in such tests are "no" responses, we reasoned that a closer examination of "no" responses might reveal memory for unattended items. We modified a classic paradigm to allow participants to indicate high and low levels of confidence in their responses. As in earlier studies, the overall proportion of "yes" responses did not differ between unattended old items and new items. However, there was a crossover effect in the "no" responses: More high-confidence "no" responses were given for new items than for unattended old items, whereas more low-confidence "no" responses were given for unattended old items than for new items. These results indicate explicit memory for unattended material presented under high perceptual load. Our findings suggest that the null effects obtained in previous studies may not have stemmed from failures of perception or memory, but rather may have been due to insufficiently sensitive memory assessment.     

Agmatine facilitates memory of an inhibitory avoidance task in adult rats

Agmatine is a new putative neurotransmitter; however, the physiological role(s) of this endogenous released polyamine is still to be determined. We investigated its cognitive effect in an inhibitory avoidance task in adult rats. Agmatine (0.1, 1, 10, and 20 mg/kg) or saline was administered ip immediately after training or 1 h before testing. Posttraining injection of agmatine facilitated (p < 0.05) memory consolidation in this task; however pretest treatment showed no effect on retrieval (p > 0.05). We suggest that the facilitatory effect of agmatine on memory consolidation in inhibitory avoidance task might be mediated through the activation of the locus coeruleus.     

Distinctiveness Benefits Novelty (and Not Familiarity), but Only Up to a Limit: The Prior Knowledge Perspective

Novelty is a pivotal player in cognition, and its contribution to superior memory performance is a widely accepted convention. On the other hand, mnemonic advantages for familiar information are also well documented. Here, we examine the role of experimental distinctiveness as a potential explanation for these apparently conflicting findings. Across two experiments, we demonstrate that conceptual novelty, an unfamiliar combination of familiar constituents, is sensitive to its experimental proportions: Improved memory for novelty was observed when novel stimuli were relatively rare. Memory levels for familiar items, in contrast, were completely unaffected by experimental proportions, highlighting their insensitivity to list‐based distinctiveness. Finally, no mnemonic advantage for conceptual novelty over familiarity was observed even when novel stimuli were extremely rare at study. Together, these results imply that novel and familiar items are processed via partially distinct mechanisms, with (at least some facets of) novelty not providing a mnemonic advantage over familiarity.     

Posttraumatic Growth and Sexual Violence: A Literature Review

Posttraumatic growth (PTG) is the positive psychological growth that a person might experience after enduring a traumatic event. PTG is a relatively new area of research identified by researchers because it represents a shift in thinking. Rather than focusing on the negative consequences of trauma, it explores the potential for positive outcomes associated with trauma. Although PTG is well documented across different types of traumas, it is unclear how this kind of growth stems from sexual violence, specifically. This review provides an overview of the literature concerning PTG that is associated with sexual violence. Results across the literature indicate that sexual violence is consistently associated with PTG. However, given the inconsistency in research designs, assessment, and operational definitions used to study PTG, many researchers suggest that it might be difficult to determine how and when PTG occurs. This study provides a literature review of the research on PTG in the aftermath of sexual violence. Important implications for future directions and trauma-based therapy are discussed and include the identification of relevant predictors, the importance of context, and how service providers might benefit from a better understanding of PTG.     

The Social Anxiety Questionnaire for Children: Cross-Cultural Assessment with a New Self-Report Measure

This study describes a series of exploratory and confirmatory factor analyses that were conducted with the 44-item Social Anxiety Questionnaire for Children- 4th version (SAQ-CIV) to identify a reduced set of items that might be used to construct a new abbreviated instrument for measuring social anxiety in children and adolescents. The fourth version of the Social Anxiety Questionnaire for Children (SAQ-CIV) was administered to 12,801 non-clinical participants (ages 9 to 15 years) from 12 Latin American countries and Spain. Exploratory and confirmatory factor analysis supported a 6-factor structure of social anxiety in children, replicating a similar structure to that of adults (Caballo et al. in Behavioral Psychology/Psicología Conductual, 18(1), 5–34, 2010; Caballo et al. in Behavior Therapy, 43(2), 313–328, 2012): 1) Interactions with the opposite sex, 2) Criticism and embarrassment, 3) Speaking in public/Talking to teachers, 4) Assertive expression of annoyance and disgust, 5) Performing in public, and 6) Interactions with strangers. Each of the factors contains 4 items, yielding an abbreviated 24-item instrument, the Social Anxiety Questionnaire for Children (SAQ-C). The present results suggest this is a reliable, valid, and culturally sensitive instrument to assess social anxiety in youth.