Gene knockout of insulin-regulated aminopeptidase: Loss of the specific binding site for angiotensin IV and age-related deficit in spatial memory

The AT₄ ligands, angiotensin IV and LVV-hemorphin 7, elicit robust effects on facilitating memory by binding to a specific site in the brain historically termed the angiotensin AT₄ receptor. The identification of the AT₄ receptor as insulin-regulated aminopeptidase (IRAP) is controversial, with other proteins speculated to be the target(s) of these peptides. In this study we have utilized IRAP knockout mice to investigate IRAP in the brain. We demonstrate that the high-affinity binding site for angiotensin IV is absent in IRAP knockout mice brain sections in parallel with the loss of IRAP immunostaining, providing irrefutable proof that IRAP is the specific high-affinity binding site for AT₄ ligands. However, our characterization of the behavioural phenotype of the IRAP knockout mice revealed a totally unexpected finding. In contrast to the acute effects of IRAP inhibitors in enhancing memory, deletion of the IRAP gene resulted in mice with an accelerated, age-related decline in spatial memory that was only detected in the Y maze paradigm. Moreover, no alterations in behaviour of the IRAP knockout mice were observed that could assist in elucidating the endogenous substrate(s). Our results highlight the importance of analysing the behavioural phenotype of knockout mice across different ages and in distinct memory paradigms.     

An examination of the structural, discriminant, nomological, and incremental predictive validity of the MSCEIT© V2.0

We examined the structural, discriminant, nomological, and incremental predictive validity of a behavioral measure of emotional intelligence, using data from two undergraduate student samples. Covariance structure modeling indicated that the eight subscales of the MSCEIT© V2.0 were best modeled with a solution consisting of three first-order factors, and supported the existence of one higher-order factor of overall emotional intelligence. Multi-group confirmatory factor analyses indicated that the higher-order factor had discriminant validity from personality and conformity. Contrary to prediction, the higher-order factor was more highly correlated to social desirability than to general mental ability or long term affect. Finally, hierarchical regression results indicated that overall emotional intelligence did not predict incremental variance in either GPA or life satisfaction.     

Bridging the Gap between Theory and Policy

Two decades ago, Alexander George observed a growing gap between academic theorists and practitioners in the formulation of foreign policy. The significance of the gap has been debated, but trends in the academy, society, and government suggest it is likely to grow.     

Links between sex-related expectations about alcohol, heavy episodic drinking and sexual risk among young men in a shantytown in Lima, Peru

CONTEXT: Alcohol use is frequently identified as a contributor to risky sexual behaviors; however, research results are mixed. Given the conflicting evidence, researchers have focused on other factors, such as expectations about alcohol's effects that might help explain the relationship of alcohol use and risky sexual behaviors. METHODS: Cross-sectional data from 312 sexually experienced males aged 18-30 in a shantytown in Lima, Peru, were used in logistic regression models to identify associations of heavy episodic drinking and sex-related expectations about alcohol with sexual risk behaviors. RESULTS: Heavy episodic drinking was associated with having had two or more sexual partners and having had sex with a casual partner in the past year (odds ratios, 2.8 and 2.5, respectively). After controlling for alcohol consumption, sex-related expectations about alcohol were associated with these high-risk sexual behaviors, as well as with not using a condom at last sex (1.2) and not using a condom at last sex with a casual partner (1.3). CONCLUSION: Beliefs about the effect of alcohol on sexual performance could help explain links between alcohol consumption and risky sexual behavior not completely accounted for by the pharmacological effects of alcohol.     

The roles of aggressive and affiliative behaviors in resource control: A behavioral ecological perspective

Extant literature in developmental psychology has documented the co-occurrence of aggressive and affiliative behaviors with various measures of social dominance. While these findings have been taken as evidence for the functional value of aggression, they have not been integrated into a more general theoretical frame accounting for contextual variation. In this paper the literature on aggression, agonism, affiliation, and social dominance is reviewed in light of behavioral ecological theory suggesting that different forms of competition (scramble and contest) determine, respectively, the use of affiliative and aggressive strategies. Results generally support the hypotheses advanced by this theory. In order to further integrate these findings suggestions for the study sequences of behavior, where reconciliations follow aggression, are made.     

Sympathetic arousal to a vestibular stressor in high and low hostile men

The aim of the present experiment was to extend the literature on hostility and a cerebral systems based model of sympathetic arousal to a vestibular-based stress. Several authors have concluded that autonomic stress reactivity in high hostile individuals must be interpersonally based, whereas healthy vestibular system functioning does not depend on interpersonal features. Utilizing a vestibular activation paradigm, skin conductance levels of 15 high hostile and 15 low hostile men were recorded after brief passive rotation about the vertical neuroaxis. It was expected that hostile individuals would exhibit higher skin conductance levels after rotation compared with low hostile individuals. The results confirmed expectations of heightened sympathetic tone among high hostiles subsequent to vestibular stress. Overall, the findings are interpreted to support a cerebral model of frontal region capacity limitation for regulation of vestibular stress that is independent of psychosocial mechanisms.     

Object-based selection in the Baylis and Driver (1993) paradigm is subject to space-based attentional modulation

Three experiments re-examined Baylis and Driver's (1993) strong evidence for object-based selection, that making relative apex location judgments is harder between two objects than within a single object, with object (figure-ground) segmentation determined solely by color-based perceptual set. Using variations of the Baylis and Driver paradigm, the experiments replicated a two-object cost. However, they also showed a large part of the two-object cost to be attributable to space-based factors, though there remained an irreducible cost consistent with 'true' object-based selection.     

Children’s Gender–Emotion Stereotypes in the Relationship of Anger to Sadness and Fear

Children’s perceptions of the emotional reactions of same- and different-sex characters in stories containing ambiguous and unambiguous emotional contexts were examined. According to the Parallel-Constraint-Satisfaction Theory (Kunda and Thagard. Psychological Review, 103, 284–308, 1996), stereotypes are more likely to be utilized in ambiguous contexts, defined here as those likely to elicit multiple emotional responses. Seventy suburban U.S. preschoolers were read vignettes describing boys or girls in ambiguous or unambiguous emotion-inducing events and reported how the vignette characters were feeling. Results suggest that the perceptions of participants were more likely to reflect gender–emotion stereotypes (e.g. perceiving males as angry and females as sad) in ambiguous contexts than in unambiguous contexts. Results are discussed in terms of children’s emerging understanding of gender–emotion stereotypes.     

Prevalence of Rape Myths in Headlines and Their Effects on Attitudes Toward Rape

The present research investigated the prevalence and effects of rape myths in newspaper headlines. In study 1, a content analysis of online news headlines from US media (N?=?555) surrounding the 2003–2004 Kobe Bryant sexual assault case showed that 10% endorsed a rape myth. In study 2, students at a mid-sized university in the mid-western USA (N?=?154) read headlines endorsing or not endorsing rape myths. Male participants exposed to myth-endorsing headlines were (a) less likely to think Bryant was guilty than those exposed to non-myth headlines, (b) more likely to hold rape-supportive attitudes than those exposed to non-myth headlines, and (c) more likely to hold rape-supportive attitudes than were female participants exposed to myth-endorsing headlines.     

A Longitudinal Analysis of Psychiatric Severity upon Outcomes Among Substance Abusers Residing in Self-Help Settings

A longitudinal analysis of psychiatric severity was conducted with a national sample of recovering substance abusers living in Oxford Houses, which are self-run, self-help settings. Outcomes related to residents' psychiatric severity were examined at three follow-up intervals over one year. Over time, Oxford House residents with high versus low baseline psychiatric severity reported significantly more days using psychiatric medication, decreased outpatient psychiatric treatment, yet no significant differences for number of days abstinent and time living in an Oxford House. These findings suggest that a high level of psychiatric severity is not an impediment to residing in self-run, self-help settings such as Oxford House among persons with psychiatric comorbid substance use disorders.