Glucocorticoid involvement in memory formation in a rat model for traumatic memory

Contextual fear conditioning under training conditions involving high stressor intensities has been proposed as an animal model for traumatic memories. The strength of memory for this task has been related to the intensity of the conditioning stressor and post-training corticosterone values. However, administration of a glucocorticoid receptor (GR) antagonist only attenuated memory for this task in rats conditioned at a moderate shock intensity (0.4 mA), but failed to influence conditioning in rats trained at a high shock intensity (1 mA). Here, we further questioned whether interfering with glucocorticoid action at the time of training might be effective in influencing contextual fear conditioning in rats trained under different shock intensities. Rats were subcutaneously injected with the glucocorticoid synthesis inhibitor metyrapone (50, 100 mg/kg) 90 min before being trained in the contextual fear conditioning task, at either 0.4 or 1 mA shock intensities. The results showed that metyrapone, in a dose-dependent manner: (i) attenuated long-term expression of contextual fear conditioning, both in 0.4- and 1 mA-trained rats; and (ii) efficiently prevented increased plasma corticosterone concentration. In addition to further supporting a facilitating role of glucocorticoids in memory consolidation, these findings suggest a critical involvement of these hormones in the formation of traumatic memories.     

“Ningún Iroqués era Mohicano”: La influencia del contenido en las tareas de razonamiento lógico

Resumen

Este estudio se centra en la influencia del contenido de la tarea en problemas de razonamiento deductivo. Se utilizaron cuatro tareas diferentes: de razonamiento proposicional, usando deferentes tipos de conectivas lógicas, silogismos lineales o series de tres términos, silogismos categoriales y la tarea selección de Wason. Para cada una de las tareas se diseñaron dos versiones: una con material temático concreto, diferente para cada tarea y una segunda versión con material abstracto, sin contenido temático concreto. Ambas versiones de la misma tarea eran isomóificas. Se administraron ambas versiones de las cuatro tareas, en el mismo orden comentado, a dos grupos de sujetos: un grupo realizó siempre primero la versión concreta y luego la abstracta y otro grupo realizó siempre la abstracta y después la concreta. Los sujetos fueron alumnos de enseñanza secundaria (3.^er año), 37 y 38 sujetos respectivamente, con una media de edad de 17 años.

Los resultados confirman que no se produce un único efecto facilitador o dificultador del contenido. En una tarea la versión de contenido resulta más fácil, en otra más dificil y en otras dos no hay diferencias. El efecto mayor se produce en aquella tarea en que los sujetos parecen disponer de un «esquema de permiso» muy claro sobre el contenido temático de la tarea. Los resultados se interpretan en base a una hipótesis de doble procesamiento sintáctico y semántico. En cuanto al efecto facilitador del orden de presentación (abstracto-concreto; concreto-abstracto) los resultados indican que la versión concreta facilita la abstracta pero que la abstracta dificulta la ejecución en la concreta. Estos resultados irían en la línea de presuponer una primacía de procesamiento semántico sobre el sintáctico.     

Rewording the Rules on Disjunctive Probability

Logic is a central and highly useful part of philosophy. Its value is particularly evident when it comes to keeping our thinking about disjunctive probabilities clear. Because of the two meanings of “or” (“just one of these statements is true,” “at least one of these statements is true”), logic can show how the likelihood of a disjunction being true can be determined quite easily. To gauge the chance that one of two or more exclusive alternatives is true, one need only sum up their respective likelihoods. And to know the chance that at least one of two or more compatible alternatives is true, one simply has to figure the chance that it is false that all of them are false!     

Favoritism,Bias, and Error in Performance Ratings of Scientists and Engineers: The Effects of Power,Status, and Numbers

In this paper we argue that the sociostructural position of groups must be taken into consideration along with motivational and cognitive processes to explain evaluations received and made by women, Blacks, Hispanics, and Asians. With this framework, we analyze performance ratings for a sample of 2,445 scientists and engineers from 24 U.S. companies and find that (a) there is more evidence of in-group favoritism than of out-group derogation; (b) high status, dominant, and majority group members enjoy favoritism expressed as a global prototype of them as competent; and (c) subordinate, minority group members overshoot in opposite ways toward other groups depending on their status and the status level of the target group. We find these effects even after controlling for self-reported productivity and for various errors inherent in the evaluation process.     

Learning under stress: the inverted-U-shape function revisited

Although the relationship between stress intensity and memory function is generally believed to follow an inverted-U-shaped curve, strikingly this phenomenon has not been demonstrated under the same experimental conditions. We investigated this phenomenon for rats' performance in a hippocampus-dependent learning task, the radial arm water maze (RAWM). Variations in stress intensity were induced using different water temperatures (25°C, 19°C, and 16°C), which elicited increased plasma corticosterone levels. During spatial training over three consecutive days, an inverted-U shape was found, with animals trained at 19°C making fewer errors than animals trained at either higher (16°C) or lower (25°C) stress conditions. Interestingly, this function was already observed by the last trial of day 1 and maintained on the first day trial of day 2. A long-term recall probe test administered under equal temperature conditions (20°C) revealed differences in performance according to the animals' former training conditions; i.e., platform searching for rats trained at 25°C was less accurate than for rats trained at either 16°C or 19°C. In reversal learning, groups trained at both 19°C and 25°C showed better performance than the 16°C group. We also found an interaction between anxiety and exploration traits on how individuals were affected by stressors during spatial learning. In summary, our findings confirm, for the first time, the existence of an inverted-U-shape memory function according to stressor intensity during the early learning and memory phases in a hippocampus-dependent task, and indicate the existence of individual differences related to personality-like profiles for performance at either high or low stress conditions.     

Neurobiological and endocrine correlates of individual differences in spatial learning ability

The polysialylated neural cell adhesion molecule (PSA-NCAM) has been implicated in activity-dependent synaptic remodeling and memory formation. Here, we questioned whether training-induced modulation of PSA-NCAM expression might be related to individual differences in spatial learning abilities. At 12 h posttraining, immunohistochemical analyses revealed a learning-induced up-regulation of PSA-NCAM in the hippocampal dentate gyrus that was related to the spatial learning abilities displayed by rats during training. Specifically, a positive correlation was found between latency to find the platform and subsequent activated PSA levels, indicating that greater induction of polysialylation was observed in rats with the slower acquisition curve. At posttraining times when no learning-associated activation of PSA was observed, no such correlation was found. Further experiments revealed that performance in the massed water maze training is related to a pattern of spatial learning and memory abilities, and to learning-related glucocorticoid responsiveness. Taken together, our findings suggest that the learning-related neural circuits of fast learners are better suited to solving the water maze task than those of slow learners, the latter relying more on structural reorganization to form memory, rather than the relatively economic mechanism of altering synaptic efficacy that is likely used by the former.     

Intentional and identity processes: A social constructionist investigation using student journals

In contrast to traditional theories of career development that focus on decision-making processes in relation to market work, [Richardson, M. S. (2004). The emergence of new intentions in subjective experience: A social/personal constructionist and relational understanding. Journal of Vocational Behavior, 64, 485-498], informed by social constructionism and considering both work and relationships, suggests that the process of emerging intentional states or intentional process is central to the broader task of constructing a life. This study was designed to investigate this process. The research situation consisted of three structured group discussions with students in a graduate class. Journals written after the group discussions constituted the data for the study. Based on the first stage of data analysis, the scope of investigation was expanded to include emerging identity states or identity process and the emotional experience of the group discussions. In the second phase of data analysis, intentional process and identity process data were analyzed for themes and the emotional experience data were coded. Results of both phases of data analysis are discussed in relation to future research and implications for practice.     

Work–Family Conflict and Turnover Intentions Among Scientists and Engineers Working in R&D

Purpose  In this study we evaluate competing models of the direct and indirect effects of work interference with family (WIF) and family interference with work (FIW) on two turnover intentions relevant to scientists and engineers: (i) leaving R&D for non-R&D work within the same organization and (ii) leaving one’s organization for another one. Design/methodology/approach  A cross-sectional design was used. Our sample consists of almost 500 scientists and engineers in dual-earner families and with dependent care responsibilities. Findings  We find some support for the domain-specific predictors-to-outcomes model: FIW indirectly (but not directly) increases intentions to change organization through work dissatisfaction. Contrary to expectations from the stress management model we find neither direct nor indirect relationships between WIF and turnover intentions. Implications  Our findings suggest that organizations that help employees manage the effects of FIW on work dissatisfaction may be able to reduce the turnover among their technical workforce. Originality/value  The study examines an overlooked outcome of work-family conflict: turnover intentions. In addition, it provides much needed attention to the implications of workfamily conflict for scientists and engineers, who have received little attention in the work-family conflict literature despite longstanding efforts to understand the relationship between marriage, parenthood, and productivity in these fields.