Pre-training anandamide infusion within the basolateral amygdala impairs plus-maze discriminative avoidance task in rats

Endocannabinoids (eCBs) modulate a variety of brain functions via activation of the widely expressed CB1 receptor. One site of high density of this receptor is the basolateral amygdala (BLA), a structure involved in the formation of aversive memories. The activation and blockade of CB1 receptors by systemic or hippocampal drug administrations have been shown to modify memory processing. However, little is known about the role of the BLA endocannabinoid system in aversive memories. Additionally, BLA endocannabinoid transmission seems to be related to emotional states, but the relevance of these effects to memory formation is still unknown. In this study we investigated the effects of the eCB anandamide (AEA) and the CB1 antagonist/inverse agonist AM251 infused into the BLA on the acquisition of an aversive memory task, concomitantly evaluating basal anxiety levels in rats. Male rats received pre-training micro-injection of AEA, AM251 or vehicle bilaterally into the BLA, and were studied with the plus-maze discriminative avoidance task (a paradigm that allows concomitant and independent evaluation of anxiety-like behavior and the memory of an aversive task). Our results showed that AEA into the BLA before training prevented memory retrieval 24 h later, as evaluated by exploration of the aversive arm of the maze, while AM251 into the BLA did not interfere with animals' performance. In addition, AEA had no effect on anxiety-like behavior (as evaluated by open arm exploration and risk assessment), while AM251 induced an anxiogenic effect. Our data indicate an important role of BLA CB1 receptors in aversive memory formation, and suggest that this involvement is not necessarily related to a possible modulation of anxiety states.     

Hippocampal tauopathy in tau transgenic mice coincides with impaired hippocampus-dependent learning and memory, and attenuated late-phase long-term depression of synaptic transmission

We evaluated various forms of hippocampus-dependent learning and memory, and hippocampal synaptic plasticity in THY-Tau22 transgenic mice, a murine tauopathy model that expresses double-mutated 4-repeat human tau, and shows neuropathological tau hyperphosphorylation and aggregation throughout the brain. Focussing on hippocampus, immunohistochemical studies in aged THY-Tau22 mice revealed prominent hyper- and abnormal phosphorylation of tau in CA1 region, and an increase in glial fibrillary acidic protein (GFAP) in hippocampus, but without signs of neuronal loss. These mice displayed spatial, social, and contextual learning and memory defects that could not be reduced to subtle neuromotor disability. The behavioral defects coincided with changes in hippocampal synaptic functioning and plasticity as measured in paired-pulse and novel long-term depression protocols. These results indicate that hippocampal tauopathy without neuronal cell loss can impair neural and behavioral plasticity, and further show that transgenic mice, such as the THY-Tau22 strain, might be useful for preclinical research on tauopathy pathogenesis and possible treatment.     

How can we enhance girls’ interest in scientific topics?

Background. Girls are considerably less interested in scientific subjects than boys. One reason may be that scientific subjects are considered to be genuinely masculine. Thus, being interested in science may threaten the self‐perception of girls as well as the femininity of their self‐image. Aims. If scientific topics that are considered to be stereotypically feminine were chosen, however, this potential threat might be overcome which, in turn, might lead to an increase in girls’ interest in science. This hypothesis was empirically tested by means of two studies. Sample. Participants were 294 (Study 1) and 190 (Study 2) Grade 8 to Grade 9 students. Method. Gender differences in students’ interest in masculine and feminine topics were investigated for a range of scientific concepts (Study 1) as well as for a given scientific concept (Study 2) for four scientific subjects (i.e., biology, physics, information technology, and statistics), respectively. Results. Both studies indicated that the mean level of girls’ scientific interest was higher when scientific concepts were presented in the context of feminine topics and boys’ level of scientific interests was higher when scientific concepts were presented in the context of masculine topics. Conclusion. Girls’ interest in science could be substantially increased by presenting scientific concepts in the context of feminine topics. Gender differences as well as individual differences in the level of interest in scientific topics may be taken into account by creating learning environments in which students could select the context in which a certain scientific concept is embedded.     

Contribution of temporal preparation and processing speed to simple reaction time in persons with Alzheimer’s disease and mild cognitive impairment

Temporal preparation was assessed in 15 Alzheimer’s disease (AD) patients, 20 persons with mild cognitive impairment (MCI) and 28 healthy older adults. Participants completed a simple reaction time task in which the preparatory interval duration varied randomly within two blocks (short versus long temporal window). Results indicated that AD and MCI patients had difficulty preparing for the shortest preparatory interval of the short temporal window. AD and MCI patients also had difficulty maintaining an optimal level of preparation up to 5 s within the short temporal window. These results suggest that AD and MCI patients might show difficulty preparing for rapidly occurring events and maintaining preparation over time. This phenomenon should be considered when using reaction time measures with such patients.     

The Five-Factor Model of Personality at the Facet Level: Association with Antisocial Personality Disorder Symptoms and Prediction of Antisocial Behavior

The association between the Five-Factor Model of personality (FFM) and antisocial personality disorder (APD) symptoms was investigated in a sample of young males with a history of severe antisocial behavior. Results were compared against those of an expert-consensus study (Lynam and Widiger Journal of Abnormal Psychology 110:401–412, 2001) and those of a recent meta-analysis (Samuel and Widiger Clinical Psychology Review 28:1326–1342, 2008) based primarily on non-antisocial samples. A high degree of similarity was observed across the three. Multivariate analysis indicated two FFM facets, Compliance and Activity, to be associated with APD symptoms. The contribution of these facets to the prospective prediction of antisocial behavior over and above that of APD symptoms and past antisocial behavior was evaluated. Compliance alone explained 8.7% of the unique variance in future antisocial behavior.     

Multiculturalism as a dimension of school climate: the impact on the academic achievement of Asian American and Hispanic youth

Multiculturalism constitutes an important element of school climate, but the relation between perceived multiculturalism and academic achievement has not been widely studied. This study examined the influence of students' perceptions of school support for multiculturalism on academic achievement among 280 Asian American and Hispanic youth, including ethnic identity and ethnocultural empathy as potential mediators. Results of structural equation modeling revealed that perceived multiculturalism was significantly positively related to ethnocultural empathy for Asian Americans and Hispanics, and that ethnocultural empathy, in turn, was predictive of academic achievement for Hispanics only. Results of bootstrapping to test for mediation effects revealed ethnocultural empathy to be a salient mediator for Hispanic youth. Although ethnic identity did not mediate the link between multiculturalism and academic achievement, ethnic identity was significantly predictive of achievement for Hispanics. On the whole, these findings suggest that fostering a school climate supportive of multiculturalism may improve empathy toward ethnic out-groups. Furthermore, schools that promote compassion and tolerance for diverse ethnic groups may achieve better academic outcomes among Hispanic youth.     

多元企业认同的身份构建及其张力调和机理

基于认同驱动的营销关系视角, 系统地探讨了基于多元企业认同的企业身份构建及其张力调和机理。具体地, 通过定性和定量相结合的方法, 首先基于社会认同理论和身份理论, 探索多元企业认同的结构; 其次, 从社会心理学和文化创新的视角, 描绘多元企业认同形成及演化过程; 最后, 探究多元企业认同的身份构建以及身份张力调和机制。在理论上将消费者-企业认同扩展到多个利益相关者与企业的认同, 探索多元企业认同的身份构建及调和过程, 揭示其背后深层作用机理。实践上为企业与客户保持长期、和谐、多赢关系提供重要依据。     

Epistemic means and ends: a reply to Hofmann

How is epistemic justification related to knowledge? Is it, as widely thought, constitutive of knowledge? Is it merely a means to knowledge, or merely a means to something else, such as truth? In a recent article in this journal, Hofmann (2005, Synthese, 146(3), 357–369) addresses these questions in attempting to defend an important argument articulated by Sartwell (1992, The Journal of Philosophy, 89(4), 167–180) and reconstructed and criticized by Le Morvan (2002, Erkenntnis: An International Journal of Analytic Philosophy, 56(2), 151–168). This Sartwellian argument purported to show that, since epistemic justification is of merely instrumental value, it is not constitutive of knowledge. In this paper, I argue that Hofmann’s defense of Sartwell fails, but that its failure brings to light some important lessons concerning the nature of justification and its relationship to truth and knowledge.