Anxiogenic-like effects of gamma-hydroxybutyric acid (GHB) in mice tested in the light-dark box

Gamma-hydroxybutyric acid (GHB) is a drug with abuse potential, popularly known as "liquid ecstasy". It is an endogenous compound of the mammalian brain which satisfies many of the criteria for consideration as a neurotransmitter or neuromodulator. In this study, the effects of acute administration of GHB (40, 80 and 120 mg/kg, ip) on anxiety, tested in the light/dark box, were examined in male mice of the OF.1 strain. Likewise, we compared the behavioural profile of GHB with that induced by mCPP (1 mg/kg, ip), a compound with known anxiogenic actions. GHB-treated mice spent notably less time in the lit area (40 and 80 mg/kg) and more time in the dark area (all doses), whereas the total number of 'rearings', transitions and latency were significantly reduced. A very similar behavioural profile was observed in mCPP-treated animals. Overall, these findings indicate that GHB exhibits anxiogenic-like properties in male mice. It is suggested that the anxiogenic effects of GHB could be related to its ability to modulate GABA and/or dopaminergic receptors.     

Drug consumption and perception among Latin American immigrants

The aim of this study is to obtain information about drug consumption, leisure activities and knowledge of community services among Spanish-speaking immigrants to prevent drug abuse in this population. Quantitative methodology was used. The field work of this study has two phases: in the first stage (2003), a survey of social perception of drugs was administered to 147 subjects. During the second stage (2004), 610 surveys were administered. Data were analysed by bivariate analysis. Usual consumption of alcohol was 40.1%, usual consumption of tobacco was 31.3%, and usual consumption of cannabis was 3.4%. Drug users considered that the main reason for drug consumption was "to have fun" (p<.03). There is a relationship between leisure time and drug use. Family plays an important role in drug abuse prevention and preventive drug abuse programs must be adapted to this population.     

Fast and accurate calculations for first-passage times in Wiener diffusion models

We propose a new method for quickly calculating the probability density function for first-passage times in simple Wiener diffusion models, extending an earlier method used by [Van Zandt, T., Colonius, H., & Proctor, R. W. (2000). A comparison of two response-time models applied to perceptual matching. Psychonomic Bulletin & Review, 7, 208-256]. The method relies on the observation that there are two distinct infinite series expansions of this probability density, one of which converges quickly for small time values, while the other converges quickly at large time values. By deriving error bounds associated with finite truncation of either expansion, we are able to determine analytically which of the two versions should be applied in any particular context. The bounds indicate that, even for extremely stringent error tolerances, no more than 8 terms are required to calculate the probability density. By making the calculation of this distribution tractable, the goal is to allow more complex extensions of Wiener diffusion models to be developed.     

阅读预期对快速阅读理解的影响的实验研究

探讨阅读预期对快速阅读的理解水平与进程的影响。实验１探讨阅读预期对快速阅读理解水平的影响。阅读文章前分别给予被试正确、中性与误导的标题提示,结果表明,不同类型的标题提示对快速阅读的理解成绩有显著的影响,而对正常速度阅读的理解成绩影响效果不显著。实验２探讨阅读预期对快速阅读过程的词句加工程度的影响。结果表明,对优生来说,正确标题提示组发现文章中锗字的成绩显著低于误导标题提示组,差生的不同标题提示组发现错字的成绩差异不显著。两个实验的结果初步表明,快速阅读文章过程会更多地利用概念推动,较少地需要材料信息。     

Effects of subchronic administration of gammahydroxybutyrate (GHB) on spatial working memory in rats

GHB, a popularly known drug as "liquid ecstasy", is a substance with abuse potential. Among the possible described side-effects after the continued consumption of GHB are amnesia and deterioration of memory. Likewise, recent studies indicate the existence of neurotoxicity in certain brain regions after its prolonged treatment. The aim of this study was to examine the effect of the subchronic administration of GHB (10 and 100 mg/kg) on spatial memory and sensoriomotor reflexes in male rats, using the Morris water maze and a battery of sensoriomotor tests, respectively. The results indicated that animals treated with GHB (10 mg/kg) showed a greater latency of escape during the phase of acquisition in the days first and third of tests, as compared with the control group (p<0.05), as well as a deterioration of grasping reflex with the two doses of GHB (p<0.01). Numerous studies indicated that the medial prefrontal cortex is a crucial neuronal substrate in the working memory and grasping reflex modulation. These results suggest that prolonged administration of GHB could alter structure and/or function of the medial prefrontal cortex, as well as its interconnections with other brain regions involved in the evaluated cognitive and neurological processes.     

Schizotypy and verbal memory in the adolescent general population

The following study examines the relationship between verbal memory deficits and schizotypal traits measured psychometrically from a non- clinical adolescent population. In this transversal analytical study participated 139 subjects. They were secondary school students, with ages ranging from 13 to 16 years old (mean= 14, 35; Sta.Dev.= 0, 548). After administrating the scales O-LIFE (psychometrical schizotypy), CVLT (verbal memory), and Letters and Numbers subtest of WAIS-III (working memory), data was analyzed utilizing Pearson correlations and mean comparison test. Results showed lack of relations between schizotypy measures and working memory. Nonetheless, some of the O-LIFE dimensions correlated with verbal memory. These findings support partly the literature reviewed. Yet, more work focused on schizotypy and cognitive deficits as risk factors are suggested.     

Achievement goals and engagement in individual and collective learning activities

The relationship between achievement goals and individual and collective learning activities was examined for 290 university students who completed two questionnaires. One assessed three achievement goals-a mastery goal and two performance goals, namely, approval seeking and advancing. The other questionnaire measured how actively students report engaging in individual and collective learning activities. Regression analyses showed that the adoption of mastery goals was associated with active engagement in both individual and collective learning, while adoption of a performance goal of approval seeking was associated with passive engagement in individual learning activities. These results are discussed in relation to their theoretical implications and in regard to the possible moderating effect of protecting self-worth.     

Microswitch technology and contingent stimulation to promote adaptive engagement in persons with minimally conscious state: a case evaluation

This study assessed whether a post-coma woman functioning at the lower end of the minimally conscious state would (a) develop adaptive responding through the use of microswitch technology and contingent stimulation, (b) consolidate and maintain her responding over time, and (c) show evidence of response-consequences awareness (learning and discrimination). The study involved an ABABB¹CB¹ sequence in which the A represented baseline phases, the B and B¹ intervention phases, and the C a control phase with continuous stimulation. Results indicated that the woman developed adaptive responding and consolidated it over the intervention phases of the study. The woman also showed evidence of being aware of response-consequences links. Potential implications and limitations of these findings are discussed.     

Sampling assumptions in inductive generalization

Inductive generalization, where people go beyond the data provided, is a basic cognitive capability, and it underpins theoretical accounts of learning, categorization, and decision making. To complete the inductive leap needed for generalization, people must make a key 'sampling' assumption about how the available data were generated. Previous models have considered two extreme possibilities, known as strong and weak sampling. In strong sampling, data are assumed to have been deliberately generated as positive examples of a concept, whereas in weak sampling, data are assumed to have been generated without any restrictions. We develop a more general account of sampling that allows for an intermediate mixture of these two extremes, and we test its usefulness. In two experiments, we show that most people complete simple one-dimensional generalization tasks in a way that is consistent with their believing in some mixture of strong and weak sampling, but that there are large individual differences in the relative emphasis different people give to each type of sampling. We also show experimentally that the relative emphasis of the mixture is influenced by the structure of the available information. We discuss the psychological meaning of mixing strong and weak sampling, and possible extensions of our modeling approach to richer problems of inductive generalization.