Basolateral amygdala inactivation impairs learned (but not innate) fear response in rats

Numerous studies have suggested that the amygdala is involved in the formation of aversive memories, but the possibility that this structure is merely related to any kind of fear sensation or response could not be ruled out in previous studies. The present study investigated the effects of bilateral inactivation of the amygdaloid complex in rats tested in the plus-maze discriminative avoidance task. This task concomitantly evaluates aversive memory (by discrimination of the two enclosed arms) and innate fear (by open-arm exploration). Wistar rats (3-5 months-old) were implanted with bilateral guide cannulae into basolateral amygdala. After surgery, all subjects were given 1 week to recover before behavioral experiments. Afterwards, in experiment 1, 15 min prior to training, 0.5 μl of saline or muscimol (1 mg/ml) was infused in each side via microinjection needles. In experiment 2 the animals received injections immediately after the training session and in experiment 3 rats were injected prior to testing session (24 h after training). The main results showed that (1) pre-training muscimol prevented memory retention (evaluated by aversive arm exploration in the test session), but did not alter innate fear (evaluated by percent time in open arms); (2) post-training muscimol impaired consolidation, inducing increased percent in aversive arm exploration in the test session and (3) pre-testing muscimol did not affect retrieval (evaluated by aversive enclosed arm exploration in the test session). The results suggest that amygdala inactivation specifically modulated the learning of the aversive task, excluding a possible secondary effect of amygdala inactivation on general fear responses. Additionally, our data corroborate the hypothesis that basolateral amygdala is not the specific site of storage of aversive memories, since retention of the previously learned task was not affected by pre-testing inactivation.     

The effects of binge MDMA on acquisition and reversal learning in a radial-arm maze task

The current study used the partially-baited radial-arm maze paradigm to study the effects of a single-treatment high-dose exposure ('binge') to MDMA (± 3,4-methylenedioxymethaphemtamine or 'Ecstasy') on memory task acquisition. Sprague-Dawley rats were administered a binge dose (4 × 10 mg/kg) of MDMA and their ability to subsequently acquire the radial-arm maze task was compared against saline controls. The MDMA-treated rats were significantly slower to learn the task and made more reference memory errors than the controls. Working memory function was found to be relatively unimpaired. Following a reversal of task rules the MDMA-treated rats were again significantly slower to acquire the appropriate rule despite having eventually achieved a similar level of overall performance as control rats. However evidence of drug tolerance was found when all rats were challenged with an acute low dose of MDMA (1 × 4.0 mg/kg) because the binge MDMA rats were relatively less impaired. Therefore, although binge treated MDMA rats were able to achieve very accurate performance equivalent to the controls they took significantly longer to do this and were less able to adapt their behavior to a change in task rules. In addition the binge treated MDMA rats displayed tolerance to acute MDMA exposure. These findings are consistent with the possibility that human Ecstasy users may show deficits in acquiring information and may experience deficits in cognitive flexibility as well as developing tolerance to the drug with repeated exposure.     

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.     

Low environmental calcium blocks long-term memory formation in a freshwater pulmonate snail

The freshwater snail Lymnaea stagnalis (L.) is considered a calciphile and exhibits reduced growth and survival in environments containing less than 20 mg/l environmental calcium. Although it has no apparent effect on survival at 20 mg/l, reducing environmental calcium increases metabolic demand, and as such we consider that this level of calcium acts as a stressor on the snail. We exposed snails to acute periods of low environmental calcium and tested their ability to form intermediate-term memory (ITM) and long-term memory (LTM) following one trial operant conditioning (1TT) to reduce aerial respiratory activity in hypoxic conditions. We also assessed whether there were changes in the electrophysiological properties of a single neuron, right pedal dorsal 1 (RPeD1), which has been demonstrated to be necessary for LTM formation. Following training in high (80 mg/l) environmental calcium, L. stagnalis formed ITM and LTM lasting 24 h and demonstrated a significant reduction in all activity measured from RPeD1; however when snails were exposed to low (20 mg/l) environmental calcium they were able to form ITM but not LTM. Although no behavioral LTM was formed, a partial reduction in RPeD1 activtiy measured 24 h after training was observed, indicating a residual effect of training. The strong effect that environmental calcium concentration had on physiology and behavior in response to training to reduce aerial respiration in L. stagnalis suggests that it is an element of gastropod husbandry that needs to be carefully considered when studying other traits. This study also indicates that L. stagnalis found naturally in low calcium environments may be less able to adapt to novel stressors than populations found in harder waters.     

不同程度考试焦虑个体对威胁性刺激注意机制的差异

本研究采用线索提示实验范式,旨在考察考试焦虑个体对与考试有关和与考试无关刺激在注意机制上的差异。研究选取被试149名,分别采用TAS,STAI-T以及BDI量表进行高、低考试焦虑被试的筛选。问卷结果显示,TAS与STAI-T、BDI均有较高的正相关。行为实验结果显示,高、低考试焦虑个体对与考试相关的刺激在注意卷入上不存在显著差异,但是与低考试焦虑个体相比,高考试焦虑个体对与考试相关的刺激上出现了注意脱离困难。     

目标设置对工作记忆成绩影响的实验研究

为了回应Locke提出的“目标设置理论仍然需要发展”的观点,本文从认知心理学的角度对目标设置理论进行了检验。结果表明：设置明确且有一定难度的目标比设置模糊或一般性目标会使被试产生更高水平的努力,从而提高成绩;设置明确但难度偏低的目标与设置模糊目标的成绩间并无显著性差异;被试对目标的可接受性程度越高,成绩越好;任务难度变量对目标难度与成绩之间的调节效应要通过被试对策略的发掘和使用以及在时间方面给予一定的压力才能得到体现。     

词汇语音学习的影响因素

摘要 词汇语音的学习受哪些因素的影响是心理语言学研究中一个重要的问题。语音回路理论认为,语音短时记忆在词汇语音的学习过程中发挥着关键性的作用,语音短时记忆能力越好越有助于词汇的学习;语音敏感性假说认为,语音意识是影响儿童词汇发展及学习的重要因素;另外一些研究者认为,语音知识可能发挥着更为基础和关键的作用,最近的研究则更加强调几种因素如何相互作用影响词汇语音的学习。本文最后提出了该领域需要进一步研究的问题。     

大学生生命认知和生命价值取向的发展特点

在生命教育的社会背景下,以上海四所高校的一年级和三年级的812名在校本科生为研究对象,运用造句和模拟遗书等投射方式,并结合小组访谈等形式,旨在测查大学生对生命过程与死亡现象的认知特征,及对生命意义的价值取向,以此探究当代大学生的生命认知和生命价值取向的发展特点。结果发现：（1）当代大学生对生命的认知以表达态度为主,具有积极向上、珍爱生命的特点;而在对死亡的认知上,则主要采用本质认知的方式进行表述,以中性、概括、简洁为主要特点;（2）总体来看,女生比男生对生命过程和死亡现象的认知更为积极,体悟更深;（3）在生命价值取向方面,当大学生更多地表现出关顾他人的价值取向,并伴有强烈的家庭责任意识。     

焦虑症状的绘画评定研究

目的:利用回归分析探讨绘画测验对焦虑状态的评定作用。方法：对290名被试实施了房子-树-人绘画投射测验和Scl90焦虑分量表测验,结果：在所考察的11种绘画特征中,有5种对焦虑具有预测性。可以建立绘画特征对焦虑进行预测的回归方程,方程具有中等程度的解释水平。两名主试评价的Kappa一致性系数均达到较高水平。结论：可以通过绘画测验评定和预测焦虑,焦虑症状的绘画测验方法具有较好的评分者信度。