Lack of the metabotropic glutamate receptor subtype 7 selectively modulates Theta rhythm and working memory

Metabotropic glutamate receptors (mGluRs) are known to play a role in synaptic plasticity and learning. We have previously shown that mGluR7 deletion in mice produces a selective working memory (WM) impairment, while other types of memory such as reference memory remain unaffected. Since WM has been associated with Theta activity (6-12 Hz) in EEGs, and since EEG abnormalities have been observed in these mice before, we studied the effect of mGluR7 gene ablation on EEG activity in the hippocampus, in particular in the Theta range, during performance of a WM task. In an eight-arm maze with four arms baited, mGluR7 knock-out (KO) and wild-type mice committed the same number of reference memory errors, whereas KOs committed more WM errors. While performing the task, KO mice showed substantially higher Theta amplitudes, and the ratio of Theta to overall EEG power was much increased. No change was seen in the Delta (0-5 Hz), or Gamma (30-40 Hz) EEG bands compared with controls. When recording EEGs during periods of rest in the home cages, no difference was seen between groups. These findings suggest that mGluR7 is important for modulation and control of Theta activity. Since only WM was affected, and only the Theta range of EEG activity was altered, these results show a correlation between Theta rhythm and WM performance, and therefore support the concept that Theta activity in the hippocampus is involved in WM storage.     

Respiration and postural sway: detection of phase synchronizations and interactions

The aim of the central nervous system in upright stance is to control an intrinsically unstable plant. Internal disturbances, such as haemodynamics and respiration, constitute an endogenous threat to equilibrium. The way CNS reacts to those perturbations was studied in this work, through the analysis of summary scores taken from posturographic and pneumographic data. Signals were recorded simultaneously during trials administered on a sample population of healthy young adults, while sitting and standing and at paced and spontaneous uncontrolled breathing. The extraction of posturographic and pneumographic parameters was accompanied by the utilization of techniques for the detection of phase synchronization in bivariate data, and the extraction of an interaction index, the mutual information MI. The effects of the biomechanical condition and respiratory amplitude on MI and summary measures were tested with a two-way ANOVA. Summary scores clearly depend on posture condition. Synchronization between breath and postural sway is always present, depends on both biomechanical condition and respiratory threat, and cannot be reduced to a simple linear relation.     

Gender Differences and Similarities in Dominance Hierarchies in Same-Gender Groups Based on Speaking Time

This study aimed at investigating whether all-women and all-men groups differed in their hierarchical organization and stability of their rank orders across time. One hundred and sixteen European, middle-class, noncollege women and men (average age: 38) participated in small-group discussions twice within a week with the same group members. Speaking time served as the behavioral dominance indicator on which group hierarchies were based. Additionally, group members rank ordered each other on dominance after each interaction. In the first session, all-men groups were more hierarchically structured than all-women groups. During each session, all-women and all-men groups showed a similar significant increase in hierarchical structuring. For both women and men, rank orders remained stable during interactions and from the first to the second session. Results are discussed in terms of three theoretical models describing dominance hierarchies.     

Smiling in a Job Interview: When Less Is More

Two studies examined the effect of applicants’ smiling on hireability. In a pre-test study, participants were asked to rate the expected behavior for four types of applicants. Newspaper reporter applicants were expected to be more serious than applicants for other jobs. In Study 1, participants were randomly assigned to be an applicant or interviewer for a newspaper reporting job. Smiling was negatively related to hiring, and smiling mediated the relation between applicants’ motivation to make a good impression and hiring. Hiring was maximized when applicants smiled less in the middle of the interview relative to the start and end. In Study 2, participants watched Study 1 clips and were randomly assigned to believe the applicants were applying to one of four jobs. Participants rated more suitability when applicants smiled less, especially for jobs associated with a serious demeanor. This research shows that job type is an important moderator of the impact of smiling on hiring.     

Existential inertia and the Aristotelian proof

International Journal for Philosophy of Religion - Edward Feser defends the ‘Aristotelian proof’ for the existence of God, which reasons that the only adequate explanation of the...     

Power increases performance in a social evaluation situation as a result of decreased stress responses

We tested whether power reduces responses related to social stress and thus increases performance evaluation in social evaluation situations. We hypothesized and found that thinking about having power reduced fear of negative evaluation and physiological arousal during a self‐presentation task (Studies 1 and 2). In Study 2, we also showed that simply thinking about having power made individuals perform better in a social evaluation situation. Our results confirmed our hypotheses that the mechanism explaining this power–performance link was that high power participants felt less fear of negative evaluation. The reduced fear of negative evaluation generated fewer signs of behavioral nervousness, which caused their performance to be evaluated more positively (serial mediation). Simply thinking of having power can therefore have important positive consequences for a person in an evaluation situation in terms of how he or she feels and how he or she is evaluated. Copyright © 2013 John Wiley & Sons, Ltd.     

Performance benefits of depression: sequential decision making in a healthy sample and a clinically depressed sample

Previous research reported conflicting results concerning the influence of depression on cognitive task performance. Whereas some studies reported that depression enhances performance, other studies reported negative or null effects. These discrepant findings appear to result from task variation, as well as the severity and treatment status of participant depression. To better understand these moderating factors, we study the performance of individuals-in a complex sequential decision task similar to the secretary problem-who are nondepressed, depressed, and recovering from a major depressive episode. We find that depressed individuals perform better than do nondepressed individuals. Formal modeling of participants' decision strategies suggested that acutely depressed participants had higher thresholds for accepting options and made better choices than either healthy participants or those recovering from depression.     

Mood effects on emotion recognition

Mood affects memory and social judgments. However, findings are inconsistent with regard to how mood affects emotion recognition: For sad moods, general performance decrements in emotion recognition have been reported, as well as an emotion specific bias, such as better recognition of sad facial expressions compared to happy expressions (negative bias). Far less research has been conducted on the influence of happy moods on emotion recognition. We primed 93 participants with happy, sad, or neutral moods and had them perform an emotion recognition task. Results showed a negative bias for participants in sad moods and a positive bias for participants in happy moods. Sad and happy moods hampered the recognition of mood-incongruent expressions; the recognition of mood-congruent expressions was not affected by moods.     

The vengeance puzzle—retributive justice or hostile aggression?

Vengeance is understood as a blend of instrumental and hostile aggression. Taking the Berkowitz neoassociationistic aggression model as a basis, 84 students received a priming manipulation (anger, fear, or control condition). Afterwards, they judged one of four vengeance scenarios that differed in victim‐perpetrator relationship (coworker vs. stranger) and in the attributed motive of the perpetrator. Priming had an influence on judgments of injustice and on anticipated fury, but no effect whatsoever on aggression (measured as the decrease in well‐being wished for the perpetrator). The type of relationship had an effect only on anticipated disappointment. The main effects of motive were found on aggression and on the anticipated feeling of the perpetrator after the act. Aggression could be predicted from the motive of the perpetrator and well‐being of the victim after the transgression. Neither anticipated fury, importance of deterrence, nor judgment of injustice predicted aggression. Aggr. Behav. 00:1–12, 2005. © 2005 Wiley‐Liss, Inc.