Contextual conditioning in rats as an animal model for generalized anxiety disorder

Animal models of psychiatric disorders are important translational tools for exploring new treatment options and gaining more insight into the disease. Thus far, there is no systematically validated animal model for generalized anxiety disorder (GAD), a severely impairing and difficult-to-treat disease. In this review, we propose contextual conditioning (CC) as an animal model for GAD. We argue that this model has sufficient face validity (there are several symptom similarities), predictive validity (it responds to clinically effective treatments), and construct validity (the underlying mechanisms are comparable). Although the refinement and validation of an animal model is a never-ending process, we want to give a concise overview of the currently available evidence. We suggest that the CC model might be a valuable preclinical tool to enhance the development of new treatment strategies and our understanding of GAD.     

Individual differences in L2 proficiency as a function of L1 proficiency

Abstract

This paper offers an illustration of the claim that some individual differences in a second language (L2) can be accounted for by individual differeaces in the first language (L1). Two studies are reported, which examined L2 performance as a function of L1 performance. In the fmt study, 65 Dutch learners of English performed reading aloud tasks in L2 (Englrsh) and L1 (Dutch). In the second study, 50 Turkish lcarners of Dutch performed reading comprehension tasks in L2 (Dutch) and L1 (Turkish) as well as L2 vocabulary and grammar tests. The results of the ht study, obtained by means of co-variance analyses, show that most of the differences in L2 performance due to grade level (grade 9 vs 11) and academic level (higher vs lower) disappeared when performance in L1 WBS taken into account. The results of the second study, obtained by means of correlational techniques, provide support for the involvement of both an L2-spcafic (vocabulary and grammar) and a non-L2-sptcific component (as indicated by L1 reading performance) in L2 reading comprehension. Although the former appeared to be more involved, non-L2-specific factors did in fact contribute positively and substantially to the L2 reading performance of adult sccond language learners. Moreover, the data of the second study gave rise to thc idea that the contribution of aon-L2-speafic factors may not be stable, but liable to changes in the come of the L2 acquisition process.     

Personality, identity styles, and religiosity: an integrative study among late adolescents in Flanders (Belgium)

The relationship between the two main dimensions of the religiosity domain (Exclusion vs. Inclusion of Transcendence and Literal vs. Symbolic) and both the Five-Factor Model of personality and Berzonsky's (1990) identity styles was investigated in a Flemish sample of late adolescents (N = 335). The results show that, whereas Exclusion vs. Inclusion is unrelated to any of the personality dimensions, Literal vs. Symbolic was strongly related to Openness to Experience and moderately to Agreeableness. Further, it was shown that Exclusion vs. Inclusion was positively related to the normative identity style, and that Literal vs. Symbolic correlated positively with the informational identity style and negatively with the diffuse/avoidant identity style. As expected, the relation between Openness to Experience and Literal vs. Symbolic was fully mediated by the informational identity style. Once Openness to Experience was taken into account, Agreeableness was no longer an important determinant of Literal vs. Symbolic.     

Advancing age progressively affects obstacle avoidance skills in the elderly

The ability to adequately avoid obstacles while walking is an important skill that allows safe locomotion over uneven terrain. The high proportion of falls in the elderly that is associated to tripping over obstacles potentially illustrates an age-related deterioration of this locomotor skill. Some studies have compared young and old adults, but very little is known about the changes occurring within different age groups of elderly. In the present study, obstacle avoidance performance was studied in 25 young (20-37 years) and 99 older adults (65-88 years). The participants walked on a treadmill at a speed of 3 km/h. An obstacle was dropped 30 times in front of the left foot at various phases in the step cycle. Success rates (successful avoidance) were calculated and related to the time available between obstacle appearance and the estimated instant of foot contact with the obstacle (available response times or ARTs ranging from 200 to more than 350 ms). In addition, latencies of avoidance reactions, the choice of avoidance strategies (long or short step strategy, LSS or SSS), and three spatial parameters related to obstacle avoidance (toe distance, foot clearance, and heel distance) were determined for each participant. Compared to the young, the older adults had lower success rates, especially at short ARTs. Furthermore, they had longer reaction times, more LSS reactions, smaller toe and heel distances, and larger foot clearances. Within the group of elderly, only the 65-69 year olds were not different from young adults with respect to success rate, despite marked changes in the other parameters measured. In particular, even this younger group of elderly showed a dramatic reduction in the amount of SSS trials compared to young adults. Overall, age was a significant predictor of success rates, reaction times, and toe distances. These parameters deteriorated with advancing age. Finally, avoidance success rates at short ARTs were considerably worse in elderly participants who sustained recurrent falls in the six-month period prior to the assessment compared to those who sustained no or only one fall. An exercise program has been shown to improve avoidance success rates, especially at short ARTs, but the training effects on the determinants of success still need to be assessed.     

Early maternal deprivation retards neurodevelopment in Wistar rats

A single 24 h period of maternal deprivation (MD) in rats has been shown to induce, in adulthood, a number of abnormalities in brain and behaviour that also occur in patients with schizophrenia. However, the short-term behavioural effects of MD have not been studied in detail. Since patients with schizophrenia are characterized by a retardation of normal development, we aimed in the present study to investigate the development of control rats and rats that were exposed to MD on postnatal day 9. Compared to control animals, MD rats showed (1) a reduction in body weight, (2) an increased in reversal latency in negative geotaxis, (3) a delayed eye opening, (4) a delayed emergence of walking and rearing; and (5) a delayed emergence of the behavioural response to amphetamine (amph). On the other hand, MD and control rats responded similarly to the non-competitive NMDA antagonist MK801. These data clearly show that early MD delays development, especially of the dopaminergic system and confirm our hypothesis that MD may represent an interesting animal model for the neurodevelopmental hypothesis of schizophrenia.     

Intelligence and family marital structure: the case of adolescents from monogamous and polygamous families among Bedouin Arabs in Israel

The levels of intelligence among Bedouin Arab adolescents from monogamous and polygamous families living in the Negev region of Israel were examined. A shortened version of the Raven's Progressive Matrices (RPM) test (S. Elbedour, T. J. Bouchard, & Y. Hur, 1997; J. Raven, J. C. Raven, & J. H. Court, 1998) was used to assess intelligence. There were no significant test score differences between adolescents from monogamous families and adolescents from polygamous families. In addition, participants with 2 mothers tended to have lower RPM scores than those with 3 or 4 mothers, and participants with related parents tended to have lower RPM scores than participants with unrelated parents. One major finding of this study is that polygamous family marital structures tended not to have deleterious effects on the Bedouin Arab adolescents' RPM test scores.     

AN EVALUATION OF TWO METHODS FOR INCREASING SELF-INITIATED VERBALIZATIONS IN AUTISTIC CHILDREN

Three children with autism and mental retardation were treated for deficits in self-initiated speech. A novel treatment package employing visual cue fading was compared with a graduated time-delay procedure previously shown to be effective for increasing self-initiated language. Both treatments included training multiple self-initiated verbalizations using multiple therapists and settings. Both treatments were efffective, with no differences in measures of acquisition of target phrases, maintenance of behavioral gains, acquisition with additional therapists and settings, and social validity.     

Paroxysmal speech disorder following left frontal brain damage

The patient was a 61-year-old female who suffered from the sudden attack of a speech disorder. The episodes of speech disorder lasted for less than 1 min, but occurred several times a day, paroxysmally. A CT revealed a low density area on the surface of the left frontal lobe and an EEG showed an abnormal wave at the frontoparietal area, more dominantly on the left. This condition was diagnosed as a kind of epilepsy. The paroxysmal speech disorder occurred very often during the 2 months after the first episode. However, with therapy using anticonvulsives and antibiotics, the condition began to improve after 4 months and disappeared completely after 6 months. It is assumed that the inflammatory change which occurred at the frontal lobe stimulated the supplementary motor area paroxysmally, and subsequently the speech disorder occurred as a kind of epilepsy.     

Towards a topological philosophy

This article examines the use of mathematical concepts in philosophy, focusing on topology, which may be viewed as a modern supplement to geometry. We show that Plato and Parmenides were already employing geometric ideas in their research, and discuss three examples of the application of topology to philosophical problems: the first concerns the analysis of the Cartesian distinction between res extensa and res cogitans, the second the ontology of possible worlds of Wittgenstein's Tractatus, and the third Leibniz's monadology. We also consider the role of topology in mathematical explanations of the sort found in science, arguing that it can perform a role in philosophy that is of comparable importance.