Opposite actions of dopamine on aversive and appetitive memories in the crab

The understanding of how the reinforcement is represented in the central nervous system during memory formation is a current issue in neurobiology. Several studies in insects provide evidence of the instructive role of biogenic amines during the learning and memory process. In insects it was widely accepted that dopamine (DA) mediates aversive reinforcements. However, the idea of DA being exclusively involved in aversive memory has been challenged in recent studies. Here, we study the involvement of DA during aversive and appetitive memories in the crab Chasmagnathus. We found that DA-receptor antagonists impair aversive memory consolidation, in agreement with previous reports in insects, while administration of DA facilitates memory formation after a weak training protocol. In contrast, DA treatment during appetitive training was found to impair formation of long-term appetitive memory. In addition, as a first step in elucidating the neuroanatomical correlates of DA action on memory, we mapped dopaminergic neurons in the central nervous system of the crab. Results of the current study, together with those obtained in a previous work about the role of octopamine (OA), suggest that both amines (DA and OA) play a dual action in memory processes. On the one hand, DA and OA mediate the aversive and the appetitive signals, respectively, throughout training, while on the other hand, they interfere with the formation of memory of the opposite sign (DA in appetitive and OA in aversive). Our results support a new understanding about the way appetitive and aversive stimuli are processed during memory formation to ensure adaptive behavior.     

Parental knowledge and adolescent adjustment: substance use and health-related quality of life

This study analyses two models (maternal and paternal) in which parental care and sources of parental knowledge moderated the relationship between parents' knowledge about their adolescents' lives and adolescents' substance use and health-related quality of life. The sample was made up of 15942 Spanish adolescents who participated in the 2006 edition of Health Behavior in School-aged Children Study. Results showed that increased parents' knowledge about their adolescents' lives reduced adolescents' substance use and increased their quality of life. With respect to the moderation relationship, a limited effect was found. However, parental care and sources of parental knowledge used by both parents generally had main effects on adolescents' substance use and health-related quality of life, with care being the most relevant variable in the health-related quality of life, while knowledge was the most relevant one for substance use.     

The benefits of chess for the intellectual and social-emotional enrichment in schoolchildren

This paper examines the benefits of regularly playing chess for the intellectual and social-emotional enrichment of a group of 170 schoolchildren from 6-16 years old. It is based on a quasi-experimental design, where the independent variable was the extracurricular activity of chess (n = 170) versus extracurricular activities of soccer or basketball (n = 60). The dependent variable was intellectual and socio-affective competence, which was measured by an IQ test (WISC-R), a self-report test (TAMAI) and a hetero-report questionnaire (teacher-tutor's criterion) applied at the beginning and the end of the academic year. In contrast to the comparison group, it was found that chess improves cognitive abilities, coping and problem-solving capacity, and even socioaffective development of children and adolescents who practice it. The results are modulated, particularly in the area socioaffective, by the personal profile of students who choose practice this activity.     

Histamine reverses a memory deficit induced in rats by early postnatal maternal deprivation

Early partial maternal deprivation causes long-lasting neurochemical, behavioral and brain structural effects. In rats, it causes a deficit in memory consolidation visible in adult life. Some of these deficits can be reversed by donepezil and galantamine, which suggests that they may result from an impairment of brain cholinergic transmission. One such deficit, representative of all others, is an impairment of memory consolidation, clearly observable in a one-trial inhibitory avoidance task. Recent data suggest a role of brain histaminergic systems in the regulation of behavior, particularly inhibitory avoidance learning. Here we investigate whether histamine itself, its analog SKF-91844, or various receptor-selective histamine agonists and antagonists given into the CA1 region of the hippocampus immediately post-training can affect retention of one-trial inhibitory avoidance in rats submitted to early postnatal maternal deprivation. We found that histamine, SKF-91844 and the H2 receptor agonist, dimaprit enhance consolidation on their own and reverse the consolidation deficit induced by maternal deprivation. The enhancing effect of histamine was blocked by the H2 receptor antagonist, ranitidine, but not by the H1 receptor antagonist pyrilamine or by the H3 antagonist thioperamide given into CA1 at doses known to have other behavioral actions, without altering locomotor and exploratory activity or the anxiety state of the animals. The present results suggest that the memory deficit induced by early postnatal maternal deprivation in rats may in part be due to an impairment of histamine mediated mechanisms in the CA1 region of the rat hippocampus.     

Res Computans: The Living Subject from Yeast to Human

Since modernity, the concept of subject supposes both an anthropocentric and a dualistic view of life and reality. In this study, we carry out an analytic interpretation of the Descartes’ notion of subject, in order to build a different dimension of the concept of subject. We discuss the activity of computing, as the manner by which the living subject relates with and in-forms the world. We further examine computing in the aging yeast as an example of living subject and we try to comprehend the maturity of the subjectivity in Descartes’ res cogitans and in our proposed res computans.     

Mechanisms of contextual control when contexts are informative to solve the task

An experiment was conducted using a human instrumental learning task with the goal of evaluating the mechanisms underlying the deleterious effect of context-switching on responding to an unambiguous stimulus when contexts are informative to solve the task. Participants were trained in a context-based reversal discrimination in which two discriminative stimuli (X and Y) interchange their meaning across contexts A and B. In context A, discriminative stimulus Z consistently announced that the relationship between a specific instrumental response (RI) and a specific outcome (O1) was in effect. Performance in the presence of stimulus Z was equally deteriorated when the test was conducted outside the training context, regardless of whether the test context was familiar (context B) or new (context C). This result is consistent with the idea that participants code all the information presented in an informative context as context-specific with the context playing a role akin to an occasion setter.     

The Problem of Many Hands: Climate Change as an Example

In some situations in which undesirable collective effects occur, it is very hard, if not impossible, to hold any individual reasonably responsible. Such a situation may be referred to as the problem of many hands. In this paper we investigate how the problem of many hands can best be understood and why, and when, it exactly constitutes a problem. After analyzing climate change as an example, we propose to define the problem of many hands as the occurrence of a gap in the distribution of responsibility that may be considered morally problematic. Whether a gap is morally problematic, we suggest, depends on the reasons why responsibility is distributed. This, in turn, depends, at least in part, on the sense of responsibility employed, a main distinction being that between backward-looking and forward-looking responsibility.     

General self-efficacy and health-related quality of life after myocardial infarction

Fatigue after myocardial infarction (MI) has been found to be distressing. A person's self-efficacy will influence his/her health behavior and plays an active role in tackling illness consequences. This study investigated associations between fatigue, disturbed sleep, general self-efficacy, and health-related quality of life (HRQoL) in a sample of 145 respondents admitted to hospital for MI two years earlier. The aim was to identify the predictive value of general self-efficacy and to elucidate mediating factors between self-efficacy and HRQoL. General self-efficacy measured four months after MI was positively related to HRQoL after two years. In tests of indirect effects, fatigue meditated the effects between self-efficacy and the physical and the mental dimension of HRQoL, respectively. The indirect effect of disturbed sleep went through that of fatigue. To conclude, patients who suffer from post-MI fatigue may need support aimed at helping them increase their self-efficacy as well as helping them adapt to sleep hygiene principles and cope with fatigue, both of which will have positive influences on HRQoL.