Synaptic plasticity in the lateral amygdala: a cellular hypothesis of fear conditioning

Fear conditioning is a form of associative learning in which subjects come to express defense responses to a neutral conditioned stimulus (CS) that is paired with an aversive unconditioned stimulus (US). Considerable evidence suggests that critical neural changes mediating the CS-US association occur in the lateral nucleus of the amygdala (LA). Further, recent studies show that associative long-term potentiation (LTP) occurs in pathways that transmit the CS to LA, and that drugs that interfere with this LTP also disrupt behavioral fear conditioning when infused into the LA, suggesting that associative LTP in LA might be a mechanism for storing memories of the CS-US association. Here, we develop a detailed cellular hypothesis to explain how neural responses to the CS and US in LA could induce LTP-like changes that store memories during fear conditioning. Specifically, we propose that the CS evokes EPSPs at sensory input synapses onto LA pyramidal neurons, and that the US strongly depolarizes these same LA neurons. This depolarization, in turn, causes calcium influx through NMDA receptors (NMDARs) and also causes the LA neuron to fire action potentials. The action potentials then back-propagate into the dendrites, where they collide with CS-evoked EPSPs, resulting in calcium entry through voltage-gated calcium channels (VGCCs). Although calcium entry through NMDARs is sufficient to induce synaptic changes that support short-term fear memory, calcium entry through both NMDARs and VGCCs is required to initiate the molecular processes that consolidate synaptic changes into a long-term memory.     

Expanding the search for a linear separability constraint on category learning

Formal models of categorization make different predictions about the theoretical importance of linear separability. Prior research, most of which has failed to find support for a linear separability constraint on category learning, has been conducted using tasks that involve learning two categories with a small number of members. The present experiment used four categories with three or nine patterns per category that were either linearly separable or not linearly separable. With overall category structure equivalent across category types, the linearly separable categories were found to be easier to learn than the not linearly separable categories. An analysis of individual participants' data showed that there were more participants operating under a linear separability constraint when learning large categories than when learning small ones. Formal modeling showed that an exemplar model could not account for many of these data. These results are taken to support the existence of multiple processes in categorization.     

Distinguishing Language from Thought: Experimental Evidence That Syntax Is Lexically Rather Than Conceptually Represented

It is generally assumed that syntax is represented linguistically rather than conceptually, consistent with the more general view that language and thought are coded separately. This claim is widely defended on logical grounds, but it has received little experimental support. In the present study, we asked Spanish and English speakers to make semantic and syntactic categorizations for pictures and their corresponding names. Consistent with past results, latencies to semantically categorize pictures and words were similar. The new finding is that participants were faster to make syntactic decisions for words compared with pictures, suggesting that syntactic features such as grammatical gender and the count-mass distinction are more closely linked to lexical than conceptual representations.     

Are Callous Unemotional (CU) Traits Enough?

A guiding question for this special section, sparked by the increasing number of studies on callous –unemotional traits (CU traits) and the DSM-5 Limited Prosocial Emotion (LPE) specifier, is whether CU traits are enough to identify a clinically meaningful subgroup of youth with conduct problems or whether other psychopathic traits contribute. Seven empirical papers and two commentary papers address this question to varying degrees and in different ways with some papers “competing” various models against one another along with other papers investigating distinct correlates of the psychopathy factors. Findings across the papers suggest that there could be benefits to examining the broader construct of psychopathy in addition to examining its underpinning dimensions rather than CU traits alone. Two commentary papers also shed light on the importance of psychopathic traits in children with Conduct Disorder (CD) and provide insights for future work on this topic. It is hoped that the articles and commentary will generate new ideas for research and practice that could have implications for the treatment of those individuals with CD and psychopathic traits.     

Maternal parenting as a mediator of the relationship between intimate partner violence and effortful control

The current study examined the relationship between intimate partner violence (IPV), maternal parenting behaviors, and child effortful control in a diverse sample of 705 families living in predominantly low-income, rural communities. Using structural equation modeling, the authors simultaneously tested whether observed sensitive parenting and/or harsh-intrusive parenting over the toddler years mediated the relationship between early IPV and later effortful control. Results suggest that parenting behaviors fully mediate this relationship. Although higher levels of IPV were associated with both higher levels of harsh-intrusive parenting and lower levels of sensitive supportive parenting, only sensitive supportive parenting was associated with later effortful control when both parenting indices were considered in the same model.     

Contagion in the Representational Field of Water Recycling: Informing New Environment Practice Through Social Representation Theory

Water shortages in Australia have highlighted an urgent need for alternative water sources, and technologically, water recycling is argued to offer the most cost‐effective, environmentally sustainable solution to these shortages. Yet public support for its implementation is low even in the drought‐stricken areas of Australia. Drawing from the theory of social representations, this study addressed community perceptions of water recycling. Three interrelated methodologies were employed in a self‐report questionnaire. Individual difference scaling/multidimensional scaling analyses of three word association tasks revealed that the emergent social representation of water recycling was contradictory in affect. Normative responses indicated an awareness of the need to use recycled water whereas the functional responses were associated with a fear of contamination. An analysis of differential use scales further revealed that the perception of contagion was specific to when recycled water had contact with the body. The discursive analysis of respondents' comments expanded on both these findings. The study identified the themata of purity/impurity as underpinning the social understanding of water recycling. Copyright © 2011 John Wiley & Sons, Ltd.     

Evidence for the Effectiveness of an Alternative Multisource Performance Rating Methodology

Despite persistent concerns as to the quality of performance information obtained from multisource performance ratings (MSPRs), little research has sought ways to improve the psychometric properties of MSPRs. Borrowing from past methodologies designed to improve performance ratings, we present a new method of presenting items in MSPRs, frame‐of‐reference scales (FORS), and test the efficacy of this method in a field and lab study. The field study used confirmatory factor analysis to compare the FORS to traditional rating scales and revealed that FORS are associated with increased variance due to dimensions, decreased overlap among dimensions, and decreased error. The laboratory study compared rating accuracy associated with FORS relative to frame‐of‐reference training (FORT) and a control group and demonstrated that FORS are associated with higher levels of accuracy than the control group and similar levels of accuracy as FORT. Implications for the design and implementation of FORS are discussed.     

Sexual behavior in Spanish adolescents of divorced parents

Marital breakup has been associated with numerous behavioral problems in children, such as sexual risk behaviors. This research is the first to examine sexual behaviors of Spanish adolescents related to whether their parents were married or divorced. Participants were 342 boys and girls aged between 14 and 18 years. The sample provided confidential information about their sexual behavior and birth control methods. Significant differences were only found in percentages of adolescents who had engaged in mutual masturbation, intercourse, or oral sex, and who had practiced these sexual relations in the last six months, in both cases, they were higher when the parents had broken their marital relationship. Regarding adolescents of divorced parents, engaging in intercourse is more likely in older teenagers who live with a stepparent. Moreover, older adolescents who were younger when parents divorced and who live in a reconstituted family, have more sexual partners. These and other findings are discussed.     

Visual attention to emotion in depression: facilitation and withdrawal processes

Attentional biases for sadness are integral to cognitive theories of depression, but do not emerge under all conditions. Some researchers have argued that depression is associated with delayed withdrawal from, but not facilitated initial allocation of attention toward, sadness. We compared two types of withdrawal processes in clinically depressed and non-depressed individuals: (1) withdrawal requiring overt eye movements during visual search; and (2) covert disengagement of attention in a modified cueing paradigm. We also examined initial allocation of attention towards emotion on the visual search task, allowing comparison of withdrawal and facilitation processes. As predicted, we found no evidence of facilitated attention towards sadness in depressed individuals. However, we also found no evidence of depression-linked differences in withdrawal of attention from sadness on either task, offering no support for the theory that depression is associated with withdrawal rather than initial facilitation of attention.     

The representation of abstract words: why emotion matters

Although much is known about the representation and processing of concrete concepts, knowledge of what abstract semantics might be is severely limited. In this article we first address the adequacy of the 2 dominant accounts (dual coding theory and the context availability model) put forward in order to explain representation and processing differences between concrete and abstract words. We find that neither proposal can account for experimental findings and that this is, at least partly, because abstract words are considered to be unrelated to experiential information in both of these accounts. We then address a particular type of experiential information, emotional content, and demonstrate that it plays a crucial role in the processing and representation of abstract concepts: Statistically, abstract words are more emotionally valenced than are concrete words, and this accounts for a residual latency advantage for abstract words, when variables such as imageability (a construct derived from dual coding theory) and rated context availability are held constant. We conclude with a discussion of our novel hypothesis for embodied abstract semantics.