Amnestic effect of intrahippocampal AM251, a CB1-selective blocker, in the inhibitory avoidance, but not in the open field habituation task, in rats

CB1 is the most abundant metabotropic receptor of the brain, being found in areas classically involved in learning and memory and present at higher density at presynaptic terminals. Different sets of evidence support the idea that endogenous ligands (endocannabinoids) to the CB1 receptors act as modulators of neurotransmission. In hippocampus, endocannabinoids seem to act as retrograde messengers mediating down-regulation of GABA release. Previous reports have described a cognitive impairment effect of cannabinoid agonists, or facilitation by antagonists. The scope of the present study is to investigate the effect of intrahippocampal administration of the CB1-selective antagonist, AM251, in two behavioral tasks. One hundred and twelve male Wistar rats with bilateral cannulae implanted in the CA1 region of the dorsal hippocampus were trained in a step-down inhibitory avoidance task (IA, footshock, 0.5 mA) or an open field habituation task (OF). Immediately, after training, animals received an infusion of 0.55, 5.5, and 55.5 ng/side of AM251 (Tocris), or its vehicle (DMSO/saline), via these cannulae. Our results show that AM251 disrupted memory consolidation of the IA task, but not the OF task, an effect that seems to be purely mnemonic since the drug showed no motor performance effects. Only the intermediate dose (5.5 ng/side) of AM251 was effective in IA and the absence of effect with the larger dose may be the consequence of non-specific binding. The fact that OF was not affected raises the possibility that this endogenous system requires some degree of aversiveness to be recruited. We propose that increased levels of endogenous cannabinoids in the hippocampus, following a training session, contribute to facilitate memory consolidation, a process that may have been disrupted with AM251.     

Alcohol intoxication reduces detection of asymmetry: an explanation for increased perceptions of facial attractiveness after alcohol consumption?

Ratings of physical attractiveness are related to degree of facial symmetry. Acute alcohol consumption affects ratings of physical attractiveness and also attenuates aspects of visual perception. We tested the hypothesis that increases in ratings of attractiveness associated with alcohol intoxication can be attributed at least in part to a reduced ability to discern facial asymmetry due to reductions in levels of visual perception. We examined whether alcohol intoxication reduces ability to detect asymmetry in approximately symmetrical images. Sober and intoxicated subjects were shown a series of simple geometric images to which they responded on whether they perceived each one to be symmetrical or asymmetrical. Intoxicated subjects were significantly less able to detect asymmetry than were sober subjects, providing support for the hypothesis.     

Linking sounds to meanings: Infant statistical learning in a natural language

The processes of infant word segmentation and infant word learning have largely been studied separately. However, the ease with which potential word forms are segmented from fluent speech seems likely to influence subsequent mappings between words and their referents. To explore this process, we tested the link between the statistical coherence of sequences presented in fluent speech and infants’ subsequent use of those sequences as labels for novel objects. Notably, the materials were drawn from a natural language unfamiliar to the infants (Italian). The results of three experiments suggest that there is a close relationship between the statistics of the speech stream and subsequent mapping of labels to referents. Mapping was facilitated when the labels contained high transitional probabilities in the forward and/or backward direction (Experiment 1). When no transitional probability information was available (Experiment 2), or when the internal transitional probabilities of the labels were low in both directions (Experiment 3), infants failed to link the labels to their referents. Word learning appears to be strongly influenced by infants’ prior experience with the distribution of sounds that make up words in natural languages.     

Sense of community,civic engagement and social well‐being in Italian adolescents

This study investigates the relationship between sense of community, civic engagement and social well‐being in a sample of Italian adolescents. Participants were 14–19 year‐old high school students (N = 566) from two demographically distinct cities. Participants completed a questionnaire assessing sense of community, social well‐being (Keyes, 1998 ), involvement in structured group activities (group membership) and civic engagement. Results showed that involvement in formal groups is associated with increased civic involvement and increased sense of community. Sense of community predicts social well‐being and explains some of the association between civic engagement and social well‐being. Findings suggest that, to increase social well‐being, it is important to provide adolescents with more opportunities to experience a sense of belonging to the peers' group and promote prosocial behaviours in the community context. Copyright © 2007 John Wiley & Sons, Ltd.     

The ‘Anti-Social’ Nature of Prosocial Research; A Psychosocial Critique

This article provides a critical review of recent psychological articles on prosocial behaviour. Even though it focuses on a specific section of this literature – giving to charities and prosocial responses to humanitarian disasters – the paper aims to offer a wider critique as it interrogates the epistemological and methodological underpinnings of the prosocial literature as a whole. It aims to illustrate how the problematic aspects of traditional quantitative, deductive, experimental research in prosocial behaviour in general, when applied to giving to charities, preclude a deeper and more complex understanding of a phenomenon quintessentially social and altruistic. I identify three specific issues that make mainstream approaches to prosocial behaviour problematic and limited in scope. The first relates to the insularity of mainstream psychology and the lack of contextualisation of its findings, in particular the problematic neglect of ideological and socio-historical factors in prosocial behaviour. The second relates to mainstream psychology's disregard for the role played by conflict, contradiction and ambivalence, in attitudes and decision making as well as in the emotional aspects of prosocial behaviour. The third looks at the constraints imposed by scientifically inspired methods, how they predetermine the range of participants' responses and make it hard to apply the findings to real life situations. I claim that these epistemological and methodological constraints severely limit the applicability and comprehensiveness of current research. The discussion of these issues is woven through the review and uses some specific studies to illustrate the limitations imposed by these constraints. Throughout the paper I also argue for the need to incorporate a psychosocial approach to research into prosocial behaviour.     

Retrieval practice improves learning in children with diverse visual word recognition skills

ABSTRACT

A large body of research shows that performing tests is more beneficial for the retention of studied materials than restudying those materials, a phenomenon termed “testing-effect”. A contemporary debate on the testing effect literature concerns whether the benefits of tests are equivalent for individuals with different cognitive skills, as the capacity to decode written words, for example. In the current study, we approached this issue in two experiments by examining whether testing is equally beneficial for children with diverse visual word decoding skills. To achieve this goal, we recruited sixth and fourth grade children (experiments 1 and 2, respectively) and administered a reading aloud task to assess their visual word recognition skills, and administered a memory task about an encyclopedic text to promote the testing effect. Memory for the restudied/tested contents of the encyclopedic text were probed after a seven-day interval, and although children from both experiments showed robust testing effects, such effects were not associated with their visual word decoding skills. These findings suggest that children with diverse word decoding skills can be benefited by retrieval practice.     

Shameful selves: Women's feelings of inadequacy and constructed façades

This paper explores women's experiences of shame as a political, existential and psychological emotional state. In particular, it focuses on women's accounts of the specific shameful experiences containing the employment of a ‘façade’ to protect the ‘true’ self constructed as inadequate and shameful. The key argument in this paper is that women's shame should be understood as discursively, politically and psychodynamically over-determined. It therefore presents a reading of women's shame that brings together Foucauldian ideas of self-surveillance and positioning in discourse, with a psychodynamic theorization of shame as resulting from a constant negotiation between external forces and internal agencies. The paper also argues for the necessity of a multiplicity of readings to make adequate sense of such over-determination.      

Differential role of the hippocampal endocannabinoid system in the memory consolidation and retrieval mechanisms

CB1 cannabinoid receptors are abundantly expressed in the brain, with large concentrations present in the hippocampus, a brain structure essential for memory processing. In the present study, we have investigated the possible modulatory role of the endocannabinoid system in the dorsal hippocampus upon the different phases of memory processing of an aversive task. AM251, a selective antagonist of CB1 receptors, and anandamide, an endogenous agonist of cannabinoid receptors, were bilaterally infused into the dorsal hippocampus of male Wistar rats either before training, immediately after training, or before test in the step-down inhibitory avoidance (IA) task. Results showed that pre-training infusion of CB1 drugs did not influence the acquisition of the task. In contrast, post-training infusion of the CB1 antagonist disrupted while the antagonist facilitated memory consolidation of IA. The post-training results demonstrate that memory consolidation depends on the integrity of the endocannabinoid system in the CA1 region of the dorsal hippocampus. While we still have no direct proof of endocannabinoids released there after an aversive task such as IA, these results suggests that (a) AM251 acts blocking the binding of endogenously released cannabinoids and (b) exogenously supplemented anandamide may be adding its contribution to the action of the endogenously released pool. Considering our data and the higher density of CB1 receptors present in the GABAergic interneurons, we propose them as the putative target of the endocannabinoid modulation of memory, a hypothesis that needs to be proven. In addition, pre-test infusion of the CB1 receptor antagonist facilitated while infusion of the agonist did not affect memory retrieval of IA. The completely opposite action of the same drug upon memory at the post-training (consolidation) and pre-test (recall) contexts suggests that some durable change took place in the CA1 region during the consolidation process that modified the logical attributes of the pharmacological response, i.e., the drug response changed from memory disruption to memory facilitation. A similar phenomenon was previously described by us in the M4 cholinergic muscarinic subsystem in the hippocampus for the same task (Diehl, F., Fürstenau, L. O., Sanchez, G., Camboim, C., de Oliveira Alvares, L., Lanziotti, V. B., et al. (2007). Facilitatory effect of the intra-hippocampal pretest administration of MT3 in the inhibitory avoidance task. Behavioral Brain Research, 177(2), 227-231), but the biological nature of such change in the local neural circuitry remains to be investigated.     

Sexism, Vocational Goals, and Motivation as Predictors of Men’s and Women’s Career Choice

In the present study we analyzed the impact of vocational goals, sexist attitudes toward women, and motivation on career choice, in a sample of 448 Spanish college students (65.2% women and 34.1% men). Although we found some similarities between men and women in terms of their motivational orientations (extrinsic vs. intrinsic) and vocational goals, men’s extrinsic motivations appear to differ depending on the college major. We also found differences in sexist attitudes toward women by gender and chosen major: both male and female students enrolled in technical majors reported the most sexist attitudes (both hostile and benevolent). These findings underline the importance of taking sexist attitudes toward women into account in attempts to explain gender differences in career choice, something which has been largely overlooked in the research to date.