NMDA Receptor Modulation of Incidental Learning in Pavlovian Context Conditioning.

Rats exposed to a footshock show conditional fear when reexposed to the shock context. Immediate presentation of shock after placement in the context significantly reduces this fear. Preexposure to the context in the absence of shock, coupled with a minimum preshock interval during training, overcomes this immediate shock deficit. Because rats learn about the context during preexposure and express that learning after being reinforced, the context preexposure effect is an aversive analogue of latent learning. The authors examined the effect of the N-methyl-D-aspartate (NMDA) receptor antagonist D,L-2-amino-5-phosphovalerate (APV) on the facilitatory effect of context preexposure. Rats were preexposed to a chamber after APV administration. The next day they were placed in the same chamber without drug and received shock 35 s later. APV blocked the facilitatory effect of preexposure. Therefore NMDA receptors are important for contextual latent learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Opioid Receptors Regulate the Extinction of Pavlovian Fear Conditioning.

Rats received a single pairing of an auditory conditioned stimulus (CS) with a footshock unconditioned stimulus (US). The fear (freezing) that had accrued to the CS was then extinguished. Injection of naloxone prior to this extinction significantly impaired the development of extinction. This impairment was mediated by opioid receptors in the brain and was not observed when naloxone was injected after extinction training. Finally, an injection of naloxone on test failed to reinstate extinguished responding that had already accrued to the CS. These experiments show that opioid receptors regulate the development, but not the expression, of fear extinction and are discussed with reference to the roles of opioid receptors in US processing, memory, and appetitive motivation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When danger lurks in the background: Attentional capture by animal fear-relevant distractors is specific and selectively enhanced by animal fear.

Across 2 experiments, a new experimental procedure was used to investigate attentional capture by animal fear-relevant stimuli. In Experiment 1 (N = 34), unselected participants were slower to detect a neutral target animal in the presence of a spider than a cockroach distractor and in the presence of a snake than a large lizard distractor. This result confirms that phylogenetically fear-relevant animals capture attention specifically and to a larger extent than do non-fear-relevant animals. In Experiment 2 (N = 86), detection of a neutral target animal was slowed more in the presence of a feared fear-relevant distractor (e.g., a snake for snake-fearful participants) than in presence of a not-feared fear-relevant distractor (e.g., a spider for snake-fearful participants). These results indicate preferential attentional capture that is specific to phylogenetically fear-relevant stimuli and is selectively enhanced in individuals who fear these animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Amygdala Modulates Hippocampus-Dependent Context Memory Formation and Stores Cue-Shock Associations.

Preexposing rats to the context facilitates subsequent contextual fear conditioning. This effect depends on the hippocampus (J. W. Rudy, R. M. Barrientos, & R. C. O'Reilly, 2002). The authors report that inactivating the basolateral region of the amygdala (BLA) by injecting muscimol, a GABAA agonist, before or after preexposure reduced this effect. In contrast, bilateral injections of anisomycin, a protein synthesis inhibitor, into BLA did not impair the consolidation of the context memory. However, when injected after fear conditioning, anisomycin impaired consolidation of both contextual and auditory-cue fear conditioning. Results are consistent with 2 ideas about the amygdala's contribution to memory: (a) It modulates memory formation in other regions of the brain, and (b) it is a storage site for cue-shock associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Temporal encoding in fear conditioning revealed through associative reflex facilitation": Correction to Lindquist and Brown (2004).

Reports an error in "Temporal Encoding in Fear Conditioning Revealed Through Associative Reflex Facilitation" by Derick H. Lindquist and Thomas H. Brown (Behavioral Neuroscience, 2004[Apr], Vol 118[2], 395-402). The article contained several errors. On page 396, second paragraph, the sentence beginning on line 6 should read as follows: "Having a stable baseline is critical for studies of reflex facilitation because the experimental designs invariably entail repetitive CR testing, if only to achieve reasonable statistical power (see Choi et al., 2001b; Lindquist & Brown, 2004)." On page 400, the first heading should read as follows: "Comparison of New and Old Reflex Facilitation Procedures." On page 400, the first sentence under the abovementioned heading should read as follows: "We decided not to use the original measure of reflex facilitation, developed by J. S. Brown et al. (1951), because it suffers from severe interpretational limitations, elaborated in detail elsewhere (Choi et al., 2001b; Leaton & Cranney, 1990; Lindquist & Brown, 2004)." (The following abstract of the original article appeared in record 2004-12681-016.) Temporal encoding in Pavlovian fear conditioning was examined through conditional facilitation of the short-latency (Rl) component of the rat eyeblink reflex. Rats were fear-conditioned to a tone conditional stimulus (CS) with either a 3- or 9-s interstimulus interval (ISI) between CS onset and the onset of the grid-shock unconditional stimulus (US). Rl facilitation was tested over 2 days, in counterbalanced order, at a latency of 3 s and 9 s from CS onset. CS-produced Rl facilitation, the conditional response (CR), was 3-4 times larger when the test latency equaled the conditioning ISI. These results, coupled with the known neurophysiology of Rl facilitation, suggest that this CR could disclose differences in the time course of CS-generated output from the amygdala when driven by cortical versus subcortical CS-CR pathways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motivational bases of the public goods problem.

Compared 2 motivational bases for not contributing to a public good, desire to "free ride" (or greed) and fear of being a "sucker," among 110 Japanese undergraduates. It was hypothesized that these 2 types of motivation would be activated under different situations. When a public good was provided conjunctively, fear would have a strong effect but greed would not; when a public good was disjunctively provided, greed would have a strong effect but fear would not. In addition, it was predicted that the greater mutual trust existing among friends would make them contribute more than strangers would in the conjunctive condition but would make no difference in the disjunctive condition. Three types of production rules, in which a public good was conjunctively, disjunctively, or additively produced on the basis of members' contributions, were experimentally created. Half of the groups in each condition consisted of total strangers, and the other half consisted of friends. The hypotheses were supported when the size of the public good (bonus points) was relatively large. Also, Ss responded similarly in the conjunctive condition and in the additive condition. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

大学生负面评价恐惧、人际关系困扰与主观幸福感的关系研究

以569名大学生为被试,采用简明负面评价恐惧量表、大学生人际关系综合诊断量表及总体幸福感量表进行问卷调查,探讨负面评价恐惧对大学生主观幸福感的影响过程及人际关系困扰的中介作用机制。结果表明：负面评价恐惧女大学生得分显著高于男大学生,并存在显著年级差异;人际关系困扰总分及待人接物、异性交往两个因子男大学生得分显著高于女大学生,并在交际交友和异性交往两个因子上存在显著年级差异;大学生主观幸福感性别和年级差异不显著;负面评价恐惧与人际关系困扰总分及各因子呈显著正相关,与主观幸福感呈显著负相关;负面评价恐惧对主观幸福感有显著的直接效应,人际关系困扰在负面评价恐惧与主观幸福感之间起部分中介作用。     

基于平行系统的恐怖突发事件下恐惧传播的仿真研究

理解恐怖突发事件下公众对恐惧的反应是反恐的一个非常关键性的问题. 针对恐怖突发事件下恐惧传播的演化过程, 应用平行系统的思想, 采用仿真软件Stella构建了恐惧传播演化的人工系统. 此研究主要有两个目的: 1)恐怖事件发生后, 在一个城市中影响恐惧传播的关键性要素有哪些; 2)分析恐惧如何演化传播. 研究表明, 恐惧的传播具有一定的规律性, 社区干扰越强, 恐惧传播的时间将会延长; 恐怖事件发生之初, 风险感知能力增长较快但下降较慢. 这些发现对理解恐怖突发事件下公众对恐惧的反应具有较强的指导意义.     

Single neurons in the medial prefrontal cortex of the rat exhibit tonic and phasic coding during trace fear conditioning.

Trace fear conditioning is a learning task that requires the association of an auditory conditioned stimulus (CS) and a shock unconditioned stimulus (US) that are separated by a 20-s trace interval. Single neuron activity was recorded from the prelimbic and infralimbic areas of the medial prefrontal cortex in rats during trace fear conditioning or nonassociative unpaired training. Prelimbic neurons showed learning-related increases in activity to the CS and US, whereas infralimbic neurons showed learning-related decreases in activity to these stimuli. A subset of prelimbic neurons exhibited sustained increases in activity during the trace interval. These sustained prelimbic responses may provide a bridging code that allows for overlapping representations of CS and US information within the trace fear conditioning circuit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resolving Apparent Contradictions Concerning the Relationships Among Fear or Anxiety and Aggression During Lactation: Theoretical Comment on D'Anna, Stevenson, and Gammie (2005).

Pregnancy and lactation involve dramatic changes in behavior and physiology necessary for the successful production and sustenance of offspring. This requires numerous processes to emerge and be coordinated in a finely tuned manner. Reduced corticotropin releasing factor (CRF) receptor activity and hypothalamic-pituitary-adrenal function are thought to be involved in numerous functions during lactation, such as reducing fear and anxiety, which in turn, is proposed to disinhibit aggressive behaviors. K. L. D'Anna, S. A. Stevenson, and S. C. Gammie (2005) reported that central infusion of urocortin 1 and 3, anxiogenic peptides that bind to CRF receptors, reduce maternal aggression in lactating mice and alter neural c-fos expression. However, the relationship between stress hormones and where they act, emotional state, and aggression during lactation is complicated, and our understanding of how these factors influence each other might benefit from a comprehensive reevaluation of these literatures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)