Effects of cocaine on briefly signaled versus completely signaled delays to reinforcement.

Key pecking by 4 pigeons was maintained by a multiple schedule consisting of two variable-interval 60-s schedules wherein each food presentation followed a nonresetting 27-s delay that was either briefly signaled at its outset or completely signaled. Brief-signal duration was adjusted so that response rates maintained by the briefly and completely signaled delays of reinforcement were similar. In general, acute administration of small to intermediate doses (0.3 to 3.0 mg/kg) of cocaine produced either small increases in response rates in both components or no change, and larger doses (5.6 to 13.0 mg/kg) decreased response rates. Chronic (i.e., daily) cocaine administration (10.0 mg/kg) resulted in tolerance to the rate-decreasing effects in both components. Cocaine's effects were generally similar whether delays were completely or briefly signaled. Discontinuation of cocaine administration and subsequent removal of the delay signals also had similar effects in both components of the multiple schedule. Taken together, these results are consistent with the view that the two types of delay signals were equally effective in maintaining responding during the variable-interval schedules.     

Substitution and caloric regulation in a closed economy.

Three experiments were conducted to study the effect of an imperfect substitute for food on demand for food in a closed economy. In Experiments 1 and 2, rats pressed a lever for their entire daily food ration, and a fixed ratio of presses was required for each food pellet. In both experiments, the fixed ratio was held constant during a daily session but was increased between sessions. The fixed ratio was increased over a series of daily sessions once in the absence of concurrently available sucrose and again when sucrose pellets were freely available. For both series, increases in the fixed ratio reduced food intake, but body weight was reduced only in the no-sucrose condition. In the sucrose condition, body weight and total caloric intake (sucrose plus food) were relatively unaffected by increases in the fixed ratio. At all fixed ratios, food intake was proportionally reduced by the intake of sucrose. In Experiment 3, monkeys obtained food or saccharin by pressing keys; the fixed ratio of presses per food pellet was increased once when tap water was each monkey's only source of fluid, again when each monkey's water was sweetened with saccharin, and a third time when each monkey had concurrent access to the saccharin solution and plain water. Increases in the fixed ratio, but not the intake of the saccharin solution, reduced each monkey's food intake. Because neither rats' sucrose nor monkeys' saccharin intakes affected the slope of the respective demand curves for food, monkeys and rats increased their daily output of presses and thereby defended their daily intake of those complementary elements of food. However, sucrose reduced rats' food intake. The relative constancy of body weight and total caloric intake in the sucrose condition is consistent with the possibility that rats tended to regulate caloric intake.     

LTP诱导期向维持或转化过程中的突触形态学特征

该研究探讨了视皮层ＬＴＰ由诱导期向维持期转化过程的突触形态学特征。实验选用１８－３０天龄的健康ＳＤ大鼠,分实验组、空白对照组及实验对照组进行电镜观测和图象分析。结果发现,在常规ＬＴＰ实验程序中强直刺激后有ＬＴＰ产生并记录８０分钟的实验组脑片标片,局部有界面曲率大于２的较大Ｕ型突触形成,这种突触多有两个以上活性区。图象分析结果显示,实验组与对照组相比较,突触的界面曲率明显增大（Ｐ〈０．０５）,活性区     

Repression-sensitization and emotion control

The internal structure of the Repression-Sensitization (R-S) Scale was examined by means of factor analysis. Following a scree test, four factors were extracted: lassitude/depression, extraversion/confidence, guilelessness/trust, and emotional lability. Concurrent validation using the Emotion Control Questionnaire and the Eysenck Personality Inventory showed that the factors extracted from the R-S Scale were related in predictable ways to existing personality constructs, but the results argue against the use of the overall R-S score as an index of emotional response style.     

Media use and political commitment: The 1992 U.S. presidential election

This study explores the relationship between media use and political commitment. Undergraduate participants answered an extensive political background questionnaire, which included measures of media use, perceived importance of information sources regarding the 1992 presidential election, and various political behaviors as an index of political commitment. Correlational analyses revealed that those who are more politically committed tend to select a variety of media sources regarding a presidential candidate. This study also investigated how informational and commitment variables were related to attitudes towards the major presidential candidates. Results observed for people expressing positive attitudes toward Perot are discussed in terms of the modern day “third party voter.”     

侧脑室注射东莨菪碱对条件反射及对海马神经元自发放电的影响

本工作采用食物性运动,条件反射方法和慢性微电极记录技术。条件反射实验在9只兔上进行,海马自发放电的实验在22只兔上进行。在9次实验中,30μg的东莨菪碱注入一侧脑室后,条件反射均受到抑制,而吃食则不受影响。注射剂量为45μg时,注射后3—5分,条件反射完全消失,而吃食行为在了次实验中不受影响,在2次实验中稍有减弱,注射后20分钟左右条件反射开始恢复;侧脑室注射40μg的东莨菪碱后,海马神经元的自发活动无明显改变。文中并对抗胆碱药作用于海马抑制条件反射的可能方式进行了讨论。     

20岁至90岁成人的某些记忆活动的变化

本工作是我们过去关于记忆年老化研究的继续。记忆材料为自行设计并与全国若干单位协作编制的“试用临床记忆量表”。受试为健康成人210名.分为7个年龄组,各组性别、文化匹配。每组有20名并作韦氏成人智力量表检查。结果:1.成年至老年记忆变化总的趋势是,50岁组开始有明显减退,70岁后又有更显著的减退。2.在智力匹配条件下记忆年老化趋势相同(20、40、50、60、70岁年龄组)。3.无意义图形再认和有关联想学习年龄差异最小,无关联想学习和人像的姓氏,爱好特点回忆年龄差异最大,表明老年人建立无关的全新的联系困难。据此,作者指出老年记忆障碍可能是编码储存和提取困难相互作用的结果。     

汉语语义记忆提取的初步研究

对汉语语义记忆的提取进行了两个实验。实验1是自由联想实验,从十三个句子中选出二十三个词作为刺激词。结果表明,以两词间所保持的常识关系来定义的语义距离,对预测自由联想的作业是有效的。实验2采用反应时技术,对真假命题判断及信息提取的时间进行了考查。实验结果与A.M.Collins等人的结果一致,说明了存储于网络不同水平上的句子其提取时间不同这一事实。结果还表明,在信息提取阶段上,汉字字形的作用不是一个重要的因素。     

测定光谱光效率的一些方法的比较

本文比较了一些有关测定光谱光效率函数的方法,概述了这些方法的各自特性及其优缺点。文章提请有关工作者注意:光谱光效率函数的各种测定方法还有从各方面继续深入探讨的必要。