A molecular dissociation between cued and contextual appetitive learning

In appetitive Pavlovian learning, animals learn to associate discrete cues or environmental contexts with rewarding outcomes, and these cues and/or contexts can potentiate an ongoing instrumental response for reward. Although anatomical substrates underlying cued and contextual learning have been proposed, it remains unknown whether specific molecular signaling pathways within the striatum underlie one form of learning or the other. Here, we show that while the striatum-enriched isoform of adenylyl cyclase (AC5) is required for cued appetitive Pavlovian learning, it is not required for contextual appetitive learning. Mice lacking AC5 (AC5KO) could not learn an appetitive Pavlovian learning task in which a discrete signal light predicted reward delivery, yet they could form associations between context and either natural or drug reward, which could in turn elicit Pavlovian approach behavior. However, unlike wild-type (WT) mice, AC5KO mice could not use these Pavlovian conditioned stimuli to potentiate ongoing instrumental behavior in a Pavlovian-to-instrumental transfer paradigm. These data suggest that AC5 is specifically required for learning associations between discrete cues and outcomes in which the temporal relationship between conditioned stimulus (CS) and unconditioned stimulus (US) is essential, while alternative signaling mechanisms may underlie the formation of associations between context and reward. In addition, loss of AC5 compromises the ability of both contextual and discrete cues to modulate instrumental behavior.In Pavlovian learning, animals form associations between discrete or contextual stimuli in their environment to shape their behavior and make appropriate responses. In discrete cue appetitive Pavlovian conditioning, a single cue with a defined onset and offset that typically activates one sensory modality is provided, immediately followed by reward delivery (Hall 2002; Domjan 2006; Ito et al. 2006). Alternatively, behavior can be driven by context, an assortment of stimuli activating a number of sensory modalities that contribute to the representation of environmental space (Balsam 1985; Rudy and Sutherland 1995; Smith and Mizumori 2006). Collectively, these stimuli make up a context that is paired with reward delivery in contextual appetitive learning. One important distinction between these two forms of learning is that in cued conditioning, there is a discrete temporal relationship between conditioned stimulus (CS) and unconditioned stimulus (US). Thus, an animal can effectively anticipate timing of reward delivery from onset and offset of CS. In vivo studies of dopamine (DA) neuron activity have suggested this discrete temporal relationship can be encoded by DA neurons (Schultz et al. 1997; Schultz 1998a). In contrast, in many contextual Pavlovian conditioning tasks, US delivery is not predicted, it is delivered as the animal explores the environment; thus, the temporal relationship between contextual stimuli and reinforcement is not an essential component of the learned associations (Fanselow 2000). These two types of environmental stimuli may be encoded differently and mediated by different neural substrates.Lesion studies have elucidated the anatomical dissociations between cued and contextual appetitive learning. Using a modified Y-maze procedure, it has been suggested that contextual appetitive learning is hippocampus- and nucleus-accumbens (NAc) dependent, while cued learning is dependent on the basolateral nucleus of the amygdala (BLA) and the NAc (Ito et al. 2005, 2006). In addition, as the NAc processes glutamatergic inputs from the amygdala and the hippocampus (Groenewegen et al. 1999; Goto and Grace 2008), recent studies have indicated that disconnecting the hippocampus from the NAc shell can disrupt contextual appetitive conditioning (Ito et al. 2008). In addition to glutamatergic inputs, the NAc, as part of the ventral striatum, receives dense dopaminergic input from midbrain nuclei (Groenewegen et al. 1999). Temporal shifts in phasic DA release in striatal regions has been correlated with appetitive Pavlovian learning (Day et al. 2007), and models of striatal function suggest that DA-dependent modification of glutamatergic transmission in the striatum may underlie reinforcement learning (Reynolds et al. 2001; Reynolds and Wickens 2002).The cAMP pathway has been implicated in plasticity and learning in a number of neuronal structures (Abel et al. 1997; Ferguson and Storm 2004; Pittenger et al. 2006). Adenylyl cyclase (AC), the enzyme that makes cAMP, has nine membrane-bound isoforms, each with different expression patterns and regulatory properties (Hanoune and Defer 2001). AC5 is highly enriched in the striatum, with very low levels of expression in other regions of the brain (Mons et al. 1998; Iwamoto et al. 2003; Kheirbek et al. 2008, 2009), and genetic deletion of AC5 (AC5KO) severely compromises DA''s ability to modulate cAMP levels in the striatum (Iwamoto et al. 2003). Previous studies have shown that AC5KO mice were severely impaired in acquisition of a cued appetitive Pavlovian learning task, while formation of action–outcome contingencies in instrumental learning was intact (Kheirbek et al. 2008). Yet, it remains unknown whether the cAMP pathway in the striatum underlies all forms of appetitive Pavlovian learning, or how it contributes to the ability of Pavlovian cues to modulate instrumental behavior.In this study, we asked if genetic deletion of AC5 selectively impairs cued or contextual appetitive learning. In addition, we tested whether loss of AC5 affects the ability of conditioned cues or contexts to modulate instrumental behavior. Our data indicate that although loss of AC5 abolishes cued appetitive learning, contextual learning is spared. Although contextual stimuli could elicit approach behavior in AC5KO mice, they could not potentiate an ongoing instrumental response, highlighting the importance of this isoform of AC in Pavlovian–instrumental interactions.     

Differences in Mathematical Performance,Creativity Potential,and Need for Cognitive Closure between Chinese and Australian Students

Research has shown that Chinese students outperform students from several Western countries on mathematics performance while some evidence has suggested that Western students perform more strongly on tests of creativity. One potential mechanism for these differences may be a higher need for cognitive closure among Chinese students. The current research compared performance on tests of mathematics and creativity among 50 students of Chinese background and 49 Australian students of Anglo‐Saxon background. As predicted, Chinese students performed better on mathematics while Australian students performed better on the measure of creativity. Australian students also had a lower score on one subscale of the need for cognitive closure, preference for predictability. Across the sample, preference for predictability showed small but significant negative correlations with several measures of creativity and positive correlations with several measures of mathematics. These findings were interpreted with respect to characteristic educational practices in both nations.     

Fairness‐related behaviour modulation by friendship is moderated by American primes in Chinese participants

Empirical studies from the fields of psychology and behavioural economics indicate that people do not like being treated unfairly and may punish those who violate the norm, even at a cost to themselves. Recent research has emphasized the relationship effect on fairness‐related behaviour but has shown conflicting results and has not focused much on the characteristics of culture. This study used the cultural priming paradigm and the Ultimatum Game (UG) to explore whether cultural primes could moderate the relationship effect on fairness‐related decision making. We primed Chinese participants with either Chinese cultural symbols or American cultural symbols and asked them to play as responders with friends or strangers in the two‐party UG (experiment 1) or in the three‐party UG (experiment 2). Results from the two experiments confirm that Chinese participants accepted unfair offers more often when the offers were made by friends than when the offers were made by strangers. However, the relationship effect was diminished after American cultural priming. These results suggest that American primes can moderate the relationship effect on fairness‐related behaviour in Chinese people. This finding may shed new light on the likelihood of exiting from the heavy reliance on social relationships in Chinese society.     

Youth gang affiliation,violence, and criminal activities: A review of motivational,risk, and protective factors

Youth gangs are a universal phenomenon attracting increasing attention; the criminal and antisocial behavior perpetuated by youth gangs has an adverse impact on local communities across the globe. Although there is an extensive body of research that has examined the problems posed by youth gangs in America (and more recently in other countries), there have been relatively fewer empirical studies that examined the factors and psychological processes that are related to youth joining and leaving gangs. This review compiles the international research on the nature of youth gangs and critically evaluates: (a) the factors that motivate engagement in and desistance from gang-related activities, (b) risk and protective factors that impact on youths' propensity for gang membership, delinquency, and violent behavior, and the adverse consequences associated with gang affiliation, and (c) the relationship between gang-affiliation, youth violence, and criminal behavior.     

Promoting the Mental Health of Immigrants: A Multicultural/Social Justice Perspective

Immigration is a major factor that is greatly contributing to the unprecedented demographic changes that are presently occurring in the United States. This article discusses the challenges encountered by immigrants, taking into account the historical, sociopolitical, economic, cultural, and psychological factors that contribute to successful adjustment and adaptation to their new environment. In doing so, it outlines a new theoretical approach to working with this unique cultural group that is embedded in a multicultural/social justice helping perspective.     

Bystanders' reactions towards co‐punishment events in the Taiwanese military: Examining the moderating effects of organizational norms

The present study examined bystanders' justice perceptions about co‐punishment events. In a sample of 169 logistic officers in the Taiwanese military, responsibility attributions (i.e. liability attributed to co‐punished persons) had a negative relationship with perceived harshness, and a positive relationship with perceived procedural justice. In addition, the effects of responsibility attributions on procedural justice were weaker if the person perceived stronger rather than weaker organizational norms of co‐punishment.     

认知评价在婚姻冲突与青少年自尊关系间的中介作用

以538名初一至高三年级青少年为被试,采用儿童对婚姻冲突的感知量表和自尊量表考察青少年父母冲突的特征、青少年对冲突的认知评价和自尊的关系.结果表明:不同年级青少年报告的父母冲突特征没有显著差异,但其对冲突的认知评价却表现出显著的年级差异,年级越高则青少年越少感受到威胁并更少对冲突做自我归因;婚姻冲突对青少年自尊的直接影响显著,但当加入认知评价作为中介变量后,直接影响不再显著,而间接作用很显著,模型检验结果支持认知评价的中介作用.     

健康人格研究述评

在适应现代生活的同时人们愈来愈重视人格健康问题,个体的健康人格状况一直受到学者们的关注.文章对国内外二十年来健康人格的理论和实证研究进展进行了系统综述.在此基础上,指出了健康人格研究领域存在的问题和将来进一步研究的方向.     

心血管疾病微创治疗的未来

心血管疾病的治疗正在经历从创伤到微创到预防的过程,实现微创的关键是如何适度、合理地使用技术,在循证医学评价系统的指导下,以人为本,以最小的创伤、最合理的成本达到最佳的疗效.达到微创医学的目的:为人类提供最人性、最科学、最先进、最规范和最全面的医疗保健服务,要求硬技术必须软着陆,需要政府的干预和政策的引导,需要社会的参与,需要学科重构.