Self-reference during explicit memory retrieval: an event-related potential analysis

Is there a specific neurocognitive system underlying the subjective sense of having a unitary continuous self across time? If so, it should be possible to isolate functions involved in the sense of self from those supporting mental activities that the self is currently engaged in. We report a study of real-time noninvasive recordings of the brain's electrical activity (event-related potentials, ERPs). We found a common neural signature that is associated with self-referential processing regardless of whether subjects are retrieving general knowledge (noetic awareness) or reexperiencing past episodes (autonoetic awareness). These ERP data are consistent with models of autobiographical memory that postulate a single locus of control over explicit memory for various kinds of self-related information. The temporal properties and scalp distribution of this novel self-reference ERP effect also suggest that it may be a neurophysiological correlate of self-related activation in medial prefrontal and parietal neocortical circuits identified in functional magnetic resonance imaging experiments.     

Exercise commitment and proneness to eating disorders in a group of physical education teachers

The study examined the association of exercise commitment with proneness to eating disorders in 50 physical education teachers who had been practicing various aerobic sports at least three times a week for at least 5 years. Significant coefficients were found between Commitment to Exercise Scale scores, the number of weekly training sessions, and scores on the Eating Disorders Inventory-2 scales measuring Maturity Fears, Social Insecurity, Perfectionism, and Asceticism. However, no relationship was found between the Commitment to Exercise Scale and the Eating Disorders Inventory-2 variables measuring anorexic tendencies (such as Drive for Thinness, Body Dissatisfaction, and Bulimia). Findings suggest the presence of some psychological factors common to both anorexic tendencies and excessive exercising but not complete overlap, so a rather more complex pattern of relationships appears to be mediated by sex and personality characteristics.     

Motion misperception caused by feedback connections: A neural model simulating the Fröhlich effect

When asked to indicate the starting position of a fast moving stimulus, observers do not indicate the actual starting position but a later position on the motion trajectory. This perceptual illusion is known as the “Fröhlich effect”. We present a neural model aimed at simulating this phenomenon based on feedforward and feedback connections. The basic simulation mechanisms seem to be compatible with the attentional and the motion extrapolation account. A comparison between simulated and empirical results showed that the model is capable of generating the same main effects as those found in the empirical data.     

Self-injurious behavior and eating disorders: the extent and nature of the association

We have reviewed the literature on the association between self-injurious behaviors (SIB) and eating disorders from the psychological-behavioral perspective. Our aims were to investigate the extent and possible reasons for the association. A literature search was conducted using the following electronic databases (1989-2005): Medline, PsychInfo and EMBASE. References in identified articles were also screened. The reported occurrence of SIB in eating disorder patients ranged between 25.4% and 55.2%. The figures for occurrence of eating disorders in SIB patients ranged between 54% and 61%. These figures indicate that there is a strong association between these disorders. Impulsivity, obsessive-compulsive characteristics, affect dysregulation, dissociation, self-criticizing cognitive style and need for control were identified as potential factors involved in the association. Early trauma such as childhood sexual abuse and possibly certain characteristics of early family environment might contribute to the development of these factors. We present a hypothetical model which includes these factors and argue that the co-existence of eating disorders and SIB in patients results from several factors being present. SIB and eating disorder symptoms may provide a means whereby patients can deal with each factor simultaneously. The clinical implications of the findings are discussed.     

Lymphocyte subsets, cardiovascular measures and anxiety state before and after a professional examination

Controversies exist regarding the impact of psychological stress on the functioning of the immune system in humans. The aim of the present study, therefore, was to evaluate whether the condition of a pre-exam stress may or not modify resting lymphocyte subsets, as well as blood pressure and heart rate. About 22 medical residents of both sexes not suffering from any medical or psychiatric disorder were included in the study. Anxiety levels were measured by means of the Hamilton rating scale for anxiety (HRSA) and anxiety traits by means of the panic-agoraphobic spectrum self-report (PAS-SR) version and the obsessive-compulsive spectrum self-report (OBS-SR) version. The results showed that systolic blood pressure and heart rate increased significantly just before sitting an examination (t(1)) in all subjects, as compared with a calm situation (t(2)), in parallel with the increase in the HRSA total score, while no significant difference was observed in lymphocyte subsets at the two assessment times. However, men had a higher number of CD4+ cells than women at t(1) and t(2), while women showed a higher heart rate at t(1). In addition, significant correlations between CD4+ lymphocyte count and heart rate at t(1) or HRSA at t(2) were detected. These findings indicate that the acute stress determined by sitting for examination provokes changes in autonomic nervous system parameters, such as blood pressure and heart rate, as well as in the subjective feeling of anxiety, as shown by the increased HRSA total scores, which were not paralleled by modifications of lymphocyte subsets. However, individual differences, related to both sex and personality traits yet to be identified, seem to have an impact in shaping the stress response.     

Software Tools in Logic Education: Some Examples

Computers are increasingly present in education and make manyresources and activities available to teachers and pupils. Newpedagogical resources development is very interesting for both.Our digital library Summa Logicae is overtly involved in innovationand pedagogical systematization. It includes some software toolsfor teaching logic developed by computer science students, andin this article we present two of these tools. The MAFIA toolis especially attractive for first year students and helps themto understand the basic concepts of logic in an interactiveway using sematic tableaux. It also allows them to solve thecrazy cases in Mafia which their fellow students from previousyears proposed. The Modelos de Kripke tool, oriented to a moreadvanced level, serves for understanding the link between theproperties of the accessibility relation and the modal formulas,which is at the basis of the current developments of modal logic.     

Integrating information about location and value of resources by white-faced saki monkeys (<Emphasis Type="Italic">Pithecia pithecia</Emphasis>)

Most studies of spatial memory in primates focus on species that inhabit large home ranges and have dispersed, patchy resources. Researchers assume that primates use memory to minimize distances traveled between resources. We investigated the use of spatial memory in a group of six white-faced sakis (Pithecia pithecia) on 12.8-ha Round Island, Guri Lake, Venezuela during a period of fruit abundance. The sakis’ movements were analyzed with logistic regressions, a predictive computer model and a computer model that simulates movements. We considered all the resources available to the sakis and compared observed distances to predicted distances from a computer model for foragers who know nothing about the location of resources. Surprisingly, the observed distances were four times greater than the predicted distances, suggesting that the sakis passed by a majority of the available fruit trees without feeding. The odds of visiting a food tree, however, were significantly increased if the tree had been visited in the previous 3 days and had more than 100 fruit. The sakis’ preferred resources were highly productive fruit trees, Capparis trees, and trees with water holes. They traveled efficiently to these sites. The sakis choice of feeding sites indicate that they combined knowledge acquired by repeatedly traveling through their home range with ‘what’ and ‘where’ information gained from individual visits to resources. Although the sakis’ foraging choices increased the distance they traveled overall, choosing more valued sites allowed the group to minimize intragroup feeding competition, maintain intergroup dominance over important resources, and monitor the state of resources throughout their home range. The sakis’ foraging decisions appear to have used spatial memory, elements of episodic-like memory and social and nutritional considerations. This contribution is part of the Special Issue “A Socioecological Perspective on Primate Cognition” (Cunningham and Janson 2007).     

Efficiency and accuracy of visual search develop at different rates from early childhood through early adulthood

Psychonomic Bulletin & Review - Most studies of visual search across the life span have focused on classic feature and conjunction searches in which observers search for a fixed, simple shape...     

The ontogeny of continuous quantity discrimination in zebrafish larvae (Danio rerio)

Animal Cognition - Several studies have investigated the ontogeny of the capacity to discriminate between discrete numerical information in human and non-human animals. Contrarily, less attention...