Activation of CB1 specifically located on GABAergic interneurons inhibits LTD in the lateral amygdala

Previously, we found that in the lateral amygdala (LA) of the mouse, WIN55,212-2 decreases both glutamatergic and GABAergic synaptic transmission via activation of the cannabinoid receptor type 1 (CB1), yet produces an overall reduction of neuronal excitability. This suggests that the effects on excitatory transmission override those on inhibitory transmission. Here we show that CB1 activation by WIN55,212-2 and Delta(9)-THC inhibits long-term depression (LTD) of basal synaptic transmission in the LA, induced by low-frequency stimulation (LFS; 900 pulses/1 Hz). The CB1 agonist WIN55,212-2 blocked LTD via G(i/o) proteins, activation of inwardly rectifying K+ channels (K(ir)s), inhibition of the adenylate cyclase-protein kinase A (PKA) pathway, and PKA-dependent inhibition of voltage-gated N-type Ca2+ channels (N-type VGCCs). Interestingly, WIN55,212-2 effects on LTD were abolished in CB1 knock-out mice (CB1-KO), and in conditional mutants lacking CB1 expression only in GABAergic interneurons, but were still present in mutants lacking CB1 in principal forebrain neurons. LTD induction per se was unaffected by the CB1 antagonist SR141716A and was normally expressed in CB1-KO as well as in both conditional CB1 mutants. Our data demonstrate that activation of CB1 specifically located on GABAergic interneurons inhibits LTD in the LA. These findings suggest that CB1 expressed on either glutamatergic or GABAergic neurons play a differential role in the control of synaptic transmission and plasticity.     

Distinct single but not necessarily repeated tetanization is required to induce hippocampal late-LTP in the rat CA1

The protein synthesis-dependent form of hippocampal long-term potentiation (late-LTP) is thought to underlie memory. Its induction requires a distinct stimulation strength, and the common opinion is that only repeated tetani result in late-LTP whereas as single tetanus only reveals a transient early-LTP. Properties of LTP induction were compared to learning processes where repetition is often the prerequisite for a long-lasting memory. However, also single events can lead to manifested memory. If LTP subserves processes of learning, similar results should be detectable for LTP. Here we show that a single tetanus is sufficient to induce late-LTP requiring dopaminergic co-transmission during induction.     

Implicit memory bias for eating- and body appearance-related sentences in eating disorders: an application of Jacoby's white noise task

Jacoby's white noise task and an explicit recognition task were used to investigate whether individuals with eating disorders demonstrate implicit memory bias and explicit memory bias, respectively, for information related to eating and body appearance. Included were 33 women with eating disorders (seven with anorexia nervosa and 26 with bulimia nervosa), 29 with nonclinical eating disorder-related concerns, and 36 healthy controls. Results showed partial support for implicit memory bias but no support for explicit memory bias. These findings suggest that eating disorders may be characterized by relative initial automatic bias for eating disorder-relevant information but not by bias at later stages of information processing. However, previous studies have demonstrated explicit memory bias in eating disorders, which is inconsistent with this interpretation. Future research is required to clarify the precise cognitive biases associated with eating disorders.     

Culture, self, and the emergence of reactance: Is there a “universal” freedom?

In this article we suggest that independent vs. interdependent aspects of the self yield different manifestations of psychological reactance and that this is especially relevant in a cross-cultural context. In Studies 1, 2, and 4 we showed that people from collectivistic cultural backgrounds (individuals holding more interdependent attitudes and values) were less sensitive to a threat to their individual freedom than people from individualistic cultural backgrounds (individuals holding more independent attitudes and values), but more sensitive if their collective freedom was threatened. In Study 3 we activated independent vs. interdependent attitudes and values utilizing a cognitive priming method and yielded similar results as the other studies hinting at the important causal role of self-related aspects in understanding reactance in a cross-cultural context.     

Does Acquisitive Self‐Presentation in Personality Self‐Ratings Enhance Validity? Evidence from two experimental field studies

The aim of the present research was to demonstrate that acquisitive self‐presentation in personality scales is not a barrier to their criterion‐related validities in human resource contexts, but rather a means to improve them. A pilot study (Study 1) with 96 job incumbents provided preliminary positive evidence. In Study 2, in the experimental group (n=99), the instructions asked job incumbents to work on a Big‐Five personality inventory (BFI‐K) as if they took part in a personnel selection procedure for a personally very attractive position. In the control group (n=93) of Study 2, job incumbents were asked to answer the inventory items honestly. As expected, the correlation between the self‐ratings of the motive to get along (i.e., which comprises emotional stability, conscientiousness, and agreeableness) and contextual performance assessments was significantly higher in the experimental group than in the control group in Study 2. Additionally, the correlation between the self‐ratings of the motive to get ahead (i.e., which comprises extraversion and openness to experience) and task performance and leadership assessments was significantly higher in the experimental group than in the control group in Study 2. It is proposed that responding to a personality inventory in a human resource decision situation should be conceptualized as a workplace simulation.     

心理治疗效果评定量表（简式）在中、德应用的心理测量学研究

419名中国和德国被试参加了本研究,并回答了若干简式心理健康量表。所选的这套量表能对心理治疗不同阶段的效果（Howard’s阶段模型：重新认识期-转变期-康复期）进行测查。本研究目的在于考察这些简式量表能否用于认知-行为治疗跨文化培训项目中的质量管理。结果显示,这些量表在中德两种文化背景下都有很高的信度和效度（聚合效度和敏感性）。尽管项目间的高相关似乎提示心理健康模型只有一个维度,但探索性因素和理论分析则更支持心理健康是一个分为8个亚维度的模型,其中每个亚维度或者与基础情绪、或者与社会性情感相连关联。本文最后就研究结果及其对心理治疗质量控制的意义进行了详细讨论     

The role of first- and second-order stimulus features for human overt attention

When processing complex visual input, human observers sequentially allocate their attention to different subsets of the stimulus. What are the mechanisms and strategies that guide this selection process? We investigated the influence of various stimulus features on human overt attention--that is, attention related to shifts of gaze with natural color images and modified versions thereof. Our experimental modifications, systematic changes of hue across the entire image, influenced only the global appearance of the stimuli, leaving the local features under investigation unaffected. We demonstrated that these modifications consistently reduce the subjective interpretation of a stimulus as "natural" across observers. By analyzing fixations, we found that first-order features, such as luminance contrast, saturation, and color contrast along either of the cardinal axes, correlated to overt attention in the modified images. In contrast, no such correlation was found in unmodified outdoor images. Second-order luminance contrast ("texture contrast") correlated to overt attention in all conditions. However, although none of the second-order color contrasts were correlated to overt attention in unmodified images, one of the second-order color contrasts did exhibit a significant correlation in the modified images. These findings imply, on the one hand, that higher-order bottom-up effects--namely, those of second-order luminance contrast--may partially account for human overt attention. On the other hand, these results also demonstrate that global image properties, which correlate to the subjective impression of a scene being "natural," affect the guidance of human overt attention.     

Mergers and group status: the impact of high,low and equal group status on identification and satisfaction with a company merger,experienced controllability,group identity and group cohesion

Although mergers are seen as tools to enhance business in today's global marketplace, they have had a low success rate, possibly because the focus has been on financial and legal issues rather than on the human factors involved. In this respect, focusing on the social psychological variables, social identity theory can provide an explanation for the failure of most mergers. An experiment based on this theory involving mergers between two workgroups was conducted to investigate the effects of merger‐related status on participants' psychological responses to the mergers. Thirty‐six small groups were assigned to three different status groups (high, low and equal status groups) using the minimal group paradigm. Most negative responses to the merger—in terms of identification with the merger group, satisfaction with the merger, common in‐group identity, group cohesion and controllability—were given by the members of the low status groups. Contrary to expectations, status was not related to the performance of the groups. Theoretical and practical implications are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Hormonal and monoamine signaling during reinforcement of hippocampal long-term potentiation and memory retrieval

Recently it was shown that holeboard training can reinforce, i.e., transform early-LTP into late-LTP in the dentate gyrus during the initial formation of a long-term spatial reference memory in rats. The consolidation of LTP as well as of the reference memory was dependent on protein synthesis. We have now investigated the transmitter systems involved in this reinforcement and found that LTP-consolidation and memory retrieval were dependent on β-adrenergic, dopaminergic, and mineralocorticoid receptor (MR) activation, whereas glucocorticoid receptors (GRs) were not involved. Blockade of the β-adrenergic signaling pathway significantly increased the number of reference memory errors compared with MR and dopamine receptor inhibition. In addition, β-adrenergic blockade impaired the working memory. Therefore, we suggest that β-adrenergic receptor activation is the main signaling system required for the retrieval of spatial memory. In addition, other modulatory interactions such as dopaminergic as well as MR systems are involved. This result points to specific roles of different modulatory systems during the retrieval of specific components of spatial memory. The data provide evidence for similar integrative interactions between different signaling systems during cellular memory processes.