Effects of callosal lesions in a model of letter perception

During cognitive tasks, the cerebral hemispheres cooperate, compete, and in general, interact via the corpus callosum. Although behavioral studies in normal and split-brain subjects have revealed a great deal about the transcallosal exchange of information, a fundamental question remains unanswered and controversial: Are transcallosal interhemispheric influences primarily excitatory or inhibitory? In this context, we examined the effects of simulating sectioning of the corpus callosum in a computational model of visual letter recognition. Differences were found, following simulated callosal sectioning, in the performance of each individual hemisphere, in the mean activation levels of hemispheres, and in the specific patterns of activity, depending on the nature of the callosal influences. Together with other recent computational modeling results, the findings are most consistent with the hypothesis that transcallosal influences are predominantly excitatory, and they suggest measures that could be examined in future experimental studies to help resolve this issue.     

The Palm IAT: A portable version of the implicit association task

The Implicit Association Test (IAT) uses reaction times to measure implicit linkages among concepts or between concepts and attributes. The Palm IAT is a simplified version of the IAT that runs on Palm Pilot or Handspring Visor personal digital assistant devices. The Palm IAT is portable, provides precise measurement, and allows for efficient data collection inside or outside the laboratory. Three studies were conducted to assess its practical usefulness. Study 1 (N = 12) replicated a previous demonstration of more favorable implicit associations for flowers than for insects. Study 2 (N = 9) found individual differences in linking the self-concept to characteristics of agency and communion. Study 3 (N = 23) found individual differences in linking the self-concept to characteristics of boldness and friendliness. Reliability of the Palm IAT is similar to reliability of the original desktop computer version. Using the Palm IAT, one can study hard-to-reach populations in unusual settings.     

Shared leadership development and team performance: A new look at the dynamics of shared leadership

The present study offers new theoretical insights into the dynamics of shared leadership. Integrating arguments from shared leadership and team development theory, we examine how shared leadership changes over the course of a project team's life cycle and how this pattern of change relates to team performance. Guided by shared leadership theory and project team literature, we also explore team‐level factors, which may alter the pattern of shared leadership development. In particular, we propose that in project teams shared leadership develops in a nonuniform way, approximating an inverted U‐shaped pattern, increasing early in the team's life cycle, peaking around the midpoint, and then decreasing in the later phase. In turn, this development pattern relates positively to team performance. We also extend theory by explaining how specific team characteristics influence the pattern of shared leadership development. Using a three‐study approach, we empirically examine the hypothesized relationships and conclude with a general discussion of the theoretical and practical implications of our findings.     

<Emphasis Type="Italic">StimulStat</Emphasis>: A lexical database for Russian

In this article, we present StimulStat – a lexical database for the Russian language in the form of a web application. The database contains more than 52,000 of the most frequent Russian lemmas and more than 1.7 million word forms derived from them. These lemmas and forms are characterized according to more than 70 properties that were demonstrated to be relevant for psycholinguistic research, including frequency, length, phonological and grammatical properties, orthographic and phonological neighborhood frequency and size, grammatical ambiguity, homonymy and polysemy. Some properties were retrieved from various dictionaries and are presented collectively in a searchable form for the first time, the others were computed specifically for the database. The database can be accessed freely at http://stimul.cognitivestudies.ru.     

Planning and self-efficacy interventions encouraging replacing energy-dense foods intake with fruit and vegetable: A longitudinal experimental study

Objective: This longitudinal experimental study compared effects of self-efficacy, planning and education-based conditions, encouraging adolescents to eat fruit and vegetable in place of energy-dense foods.

Design: Data were collected among 506 adolescents (13–18 years old) who were randomly assigned to control (n = 181), planning (n = 153) or self-efficacy (n = 172) conditions. Measurements were taken at baseline (T1), at a 2-month follow-up (T2), and at a 14-month follow-up (T3). Interventions/control group procedures were delivered at T1 and T2.

Outcome measures: Self-reports of fruit and vegetable intake (FVI) and energy-dense foods intake were collected at three times. Cognitive mediators (self-efficacy and planning) were assessed at T1 and T2. Body weight and height were objectively measured at T1 and T3.

Results and conclusions: Similar significant increases of FVI were found for planning and self-efficacy interventions (T3). The planning intervention did not influence energy-dense food intake (T3), but the self-efficacy intervention tended to result in stabilising intake (compared to an increase found in the control group). There were no effects on body weight. Similar patterns were found for the total sample and for a subsample of adolescents with overweight/obesity. The effects of interventions on FVI were mediated by respective cognitions.     

Modeling development of frontal electroencephalogram (EEG) asymmetry: Sex differences and links with temperament

Asymmetric patterns of frontal brain electrical activity reflect approach and avoidance tendencies, with stability of relative right activation associated with withdrawal emotions/motivation and left hemisphere activation linked with approach and positive affect. However, considerable shifts in approach/avoidance‐related lateralization have been reported for children not targeted because of extreme temperament. In this study, dynamic effects of frontal electroencephalogram (EEG) power within and across hemispheres were examined throughout early childhood. Specifically, EEG indicators at 5, 10, 24, 36, 48, and 72 months‐of‐age (n = 410) were analyzed via a hybrid of difference score and panel design models, with baseline measures and subsequent time‐to‐time differences modeled as potentially influencing all subsequent amounts of time‐to‐time change (i.e., predictively saturated). Infant sex was considered as a moderator of dynamic developmental effects, with temperament attributes measured at 5 months examined as predictors of EEG hemisphere development. Overall, change in left and right frontal EEG power predicted declining subsequent change in the same hemisphere, with effects on the opposing neurobehavioral system enhancing later growth. Infant sex moderated the pattern of within and across‐hemisphere effects, wherein for girls more prominent left hemisphere influences on the right hemisphere EEG changes were noted and right hemisphere effects were more salient for boys. Largely similar patterns of temperament prediction were observed for the left and the right EEG power changes, with limited sex differences in links between temperament and growth parameters. Results were interpreted in the context of comparable analyses using parietal power values, which provided evidence for unique frontal effects.     

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.     

The role of transitions to new age groups in the development of institutionalized children

Children in two institutions in St. Petersburg (Russian Federation) experienced ward transitions, one in which caregivers were trained to provide sensitive, responsive caregiving and one that conducted business as usual. A third institution eliminated transitions, received the same training, and implemented a variety of structural and employment changes designed to promote improved caregiver–child interactions and relationships. While the no‐transition comprehensive intervention group of children steadily improved in Battelle Developmental Inventory (LINC Associates, 1988 ) scores across all age intervals, the children in the institution who encouraged some positive caregiver–child interactions improved before and after, but not during, an age period that involved a transition. In contrast, the no‐treatment group displayed no developmental changes across any age period with or without a transition. These results suggest that the common institutional practice of ward transitions to new peers and caregivers is potentially disruptive to infants' and toddlers' general development, but primarily in a context in which some degree of caregiver–child sensitive and responsive interactions are encouraged.     

Psychometric properties of the Spanish version of the self-report Personality Diagnostic Questionnaire -4+ (PDQ-4+) in psychiatric outpatients

We examined the psychometric properties of the Spanish version of the self-report Personality Diagnostic Questionnaire-4+ (PDQ-4+) in a sample of 437 psychiatric outpatients. Psychometric properties were assessed through internal consistency analysis, exploratory factor analysis (EFA) and concurrent validity. Results indicate that the Spanish version of the PDQ-4+ has moderate internal consistency, which was acceptable for 7 of the 12 self-report scales. The factor structure roughly replicated the DSM-IV clusters. The presence of Personality Disorders was associated with the character dimensions of the Temperament and Character Inventory (TCI).     

Anxiety in eating disorders: a comparative study

Scientific literature shows that anxiety is an important factor in eating disorders. The aim of this case-control study was to compare the anxiety manifestations obtained by means of the Anxiety Situations and Responses Inventory of in a clinical sample of 74 females (46, anorexia nervosa; 28, bulimia) to those obtained by a control group (130 girls without disorders). The between-group ANOVA results showed higher anxiety scores in the clinical group with a medium effect size for the anxiety trait, finding a flat profile (within-group ANOVA) for the three response systems (cognitive, physiological and motor) and the four specific anxiety traits (test, interpersonal, phobic, and daily life situations). Moreover, high scores in anxiety involved a greater risk of being diagnosed with an eating disorder in the 8 bivariate comparisons. The estimations were more precise for cognitive anxiety and for the specific interpersonal anxiety trait.