Using TD learning to simulate working memory performance in a model of the prefrontal cortex and basal ganglia

Delayed-response tasks (DRTs) have been used to assess working memory (WM) processes in human and nonhuman animals. Experiments have shown that the basal ganglia (BG) and dorsolateral prefrontal cortex (DLPFC) subserve DRT performance. Here, we report the results of simulation studies of a systems-level model of DRT performance. The model was trained using the temporal difference (TD) algorithm and uses an actor-critic architecture. The matrisomes of the BG represent the actor and the striosomes represent the critic. Unlike existing models, we hypothesize that the BG subserve the selection of both motor- and cognitive-related information in these tasks. We also assume that the learning of both processes is based on reward presentation. A novel feature of the model is the incorporation of delay-active neurons in the matrisomes, in addition to DLPFC. Another novel feature of the model is the subdivision of the matrisomal neurons into segregated winner-take-all (WTA) networks consisting of delay- versus transiently-active units.Our simulation model proposes a new neural mechanism to account for the occurrence of perseverative responses in WM tasks in striatal-, as well as in prefrontal damaged subjects. Simulation results also show that the model both accounts for the phenomenon of time shifting of dopamine phasic signals and the effects of partial reinforcement and reward magnitude on WM performance at both behavioral and neural levels. Our simulation results also found that the TD algorithm can subserve learning in delayed-reversal tasks.     

Aggression in Tilapia affects immunocompetent leucocytes

Social interactions are typical behavioral patterns serving to regulate life in a group. These interactions may develop into aggression, which causes stress in the defeated animal. We used Tilapia, a commercially important fish which is aggressive, to examine how this behavior affects them and whether it induces alterations in leucocytes. Compared to dominant fish, subordinate ones had elevated glucose levels and hemolytic blood sera. In addition, cells from blood and pronephros of subordinates, when compared to dominant fish, showed qualitative changes characterized by granulocytosis and lymphopenia. Furthermore, leucocytes revealed cytoplasmic and karyoplasmic vacuolation, indicating cellular disintegration. These morphological alterations were also accompanied by impaired leukocyte function and thus may increase susceptibility to diseases and neoplasia.     

Super-Recognisers show an advantage for other race face identification

The accurate identification of an unfamiliar individual from a face photo is a critical factor in several applied situations (e.g., border control). Despite this, matching faces to photographic ID is highly prone to error. In lieu of effective training measures, which could reduce face matching errors, the selection of “super-recognisers” (SRs) provides the most promising route to combat misidentification or fraud. However, to date, super-recognition has been defined and tested using almost exclusively “own-race” face memory and matching tests. Here, across three studies, we test Caucasian participants' performance on own- and other-race face identification tasks (GFMT, MFMT, CFMT+, EFMT, CFMT-Chinese). Our findings show that compared to controls, high-performing typical recognisers (Studies 1 and 2) and SRs (Study 3) show superior performance on both the own- and other-race tests. These findings suggest that recruiting SRs in ethnically diverse applied settings could be advantageous.     

Self-esteem among college students from four Arab countries

This study had three objectives: (a) to compare undergraduates from four Arab countries on self-esteem, (b) to explore the sex-related differences in self-esteem in these four Arab countries, and (c) to examine the association of self-esteem with both per-capita income and unemployment rate. Four samples of 2,643 students were recruited from Egypt (n = 576), Kuwait (n = 674), Lebanon (n = 826), and Oman (n = 567). They responded to the Arabic version of the Rosenberg Self-Esteem Scale. Kuwaiti and Omani men had a significantly higher mean score on self-esteem than did Egyptian and Lebanese men. Egyptian women scored significantly lower than the Omani women, but the effect size was small. Regarding the sex-related differences in self-esteem, Kuwaiti men had a significantly higher mean score than did their female peers, but the effect size was small, whereas there were no significant sex differences in the other samples. The sex-related difference in self-esteem is a controversial result and it may not be replicable in different countries. It was suggested that self-esteem is associated with high per-capita income and low unemployment rate.     

A Pilot Study of Electrocortical Activity in Dysfunctional Anger: Decreased Frontocortical Activation,Impaired Attention Control,and Diminished Behavioral Inhibition

Dysfunctional anger, though not a primary clinical diagnosis per se, does present clinically as a pathological mood for which treatment is sought. Few studies have probed the neurocortical correlates of dysfunctional anger or assessed if cognitive processes, such as attention, are altered in dysfunctional anger. Though dysfunctional and high trait anger appears to be associated with biased processing of anger‐eliciting information, few studies have examined if dysfunctional anger modulates attention more generally. This is a notable gap as volitional attention control is associated with effective emotive regulation, which is impaired in dysfunctional anger and in associated acts of aggression. In this pilot study, we examined performance and electroencephalographic (EEG) profiles during a 12‐min continuous performance task (CPT) of sustained attention in 15 adults with dysfunctional anger (Anger group) and 14 controls (control group). The Anger group had fewer hits at the end of the CPT, which correlated with decreased frontocortical activation, suggesting decreased engagement of frontal circuits when attention is taxed. The Anger group had more false alarms overall indicating impaired response inhibition. Increased right cortical activation during the initial portion of CPT existed in the Anger group, perhaps reflecting greater engagement of frontal circuits (i.e. effort) during initial stages of the task compared to controls. Finally, increased overall beta₁ power, suggesting increased cortical activation, was noted in the Anger group. These EEG patterns suggest a hypervigilant state in dysfunctional anger, which may interfere with effective attention control and decrease inhibition. Such impairments likely extend beyond the laboratory setting, and may associate with aggressive acts in real life. Aggr. Behav. 38:469‐480, 2012. © 2012 Wiley Periodicals, Inc.     

Religiosity,happiness, health,and psychopathology in a probability sample of Muslim adolescents

The aim of the present study was to explore the religiosity associations with the self-rating scales of happiness, mental health, physical health, anxiety, and depression. A sample (N?=?6,339) of Muslim Kuwaiti adolescents was recruited. Their ages ranged from 15 to 18. They responded to four self-rating scales to assess religiosity, happiness, mental health, and physical health, as well as the Kuwait University Anxiety Scale, and the Center for Epidemiologic Studies-Depression Scale. Boys had higher mean scores on happiness, mental health, and physical health than did girls, whereas girls had higher mean scores on religiosity, anxiety, and depression. All the correlations were significant in both sexes. They were positive between each of the self-rating scales of religiosity, happiness, mental health, and physical health, and negative between these four rating scales and both anxiety and depression. A high-loaded and bipolar factor was disclosed and labelled “Religiosity and well-being vs. psychopathology.” In the stepwise regression, the main predictor of religiosity was happiness in both sexes.     

The relationships between subjective well-being,health, and religiosity among young adults from Qatar

Introduction: The aims of this study were to explore the associations between, and the factors of, subjective well-being, health, and religiosity among Qatari undergraduates. A sample of 113 male and 133 female college students from University of Qatar responded to the Oxford Happiness Inventory, Satisfaction With Life Scale, and Love of Life Scale, as well as to five self-rating scales to assess happiness, satisfaction with life, mental health, physical health, and religiosity. Men obtained a significantly higher mean score on self-rating of mental health than did their female counterparts. All the correlations between the scales were significant and positive. Principal components analysis yielded one factor in both the sexes and labelled “Well-being, health and religiosity.” The only predictor of religiosity was the self-rating scale of satisfaction in men and women. It was concluded that those who consider themselves as religious in the present study reported higher subjective well-being and good health.