Activity-Dependent Activation of TrkB Neurotrophin Receptors in the Adult CNS

In this paper we have investigated the hypothesis that neural activity causes rapid activation of TrkB neurotrophin receptors in the adult mammalian CNS. These studies demonstrate that kainic acid-induced seizures led to a rapid and transient activation of TrkB receptors in the cortex. Subcellular fractionation demonstrated that these activated Trk receptors were preferentially enriched in the synaptosomal membrane fraction that also contained postsynaptic glutamate receptors. The fast activation of synaptic TrkB receptors could be duplicated in isolated cortical synaptosomes with KCl, presumably as a consequence of depolarization-induced BDNF release. Importantly, TrkB activation was also observed following pharmacological activation of brain-stem noradrenergic neurons, which synthesize and anterogradely transport BDNF; treatment with yohimbine led to activation of cortical TrkB receptors within 30 min. Pharmacological blockade of the postsynaptic α1-adrenergic receptors with prazosin only partially inhibited this effect, suggesting that the TrkB activation was partially due to a direct effect on postsynaptic cortical neurons. Together, these data support the hypothesis that activity causes release of BDNF from presynaptic terminals, resulting in a rapid activation of postsynaptic TrkB receptors. This activity-dependent TrkB activation could play a major role in morphological growth and remodelling in both the developing and mature nervous systems.     

Priority roles for school psychologists as seen by superintendents

A 21-item survey, regarding school psychologist role functions, was completed by 418 Ohio school superintendents. The data indicated support for traditional child study services, inservice work with teachers, and counseling or parents and children.More limited support was found for school psychologists' participation on curricula committees, general services to secondary students or preschool children, and special functions as drug consultants, researchers, and developers of legislation.The priority level assigned by superintendents to particular tasks seemed contingent upon whether there was clear reference to children referred for evaluation or to the prevention of children's problems.Despite some variations, the data was generally consistent with responses of teachers and school psychologists previously reported.     

Motivational determinants of coalition formation

Coalition preferences of 300 male and female subjects were ascertained under varying motivational conditions. Two of the experimental conditions repeated the typical three-person coalition paradigm, with a monetary reward (extrinsic motivation) offered for the winning of a luck-determined game. In a third condition, skill rather than luck influenced the outcome and no monetary reward was given for winning (intrinsic motivation). Two additional conditions examined coalition preferences in a mixed-motive situation, with either a small or a large monetary reward offered for winning a skill-related game. In the extrinsic motivation condition, the low and the medium resource persons typically desired to coalesce, contrary to the wishes of the excluded, high resource player. In contrast, the coalition between the low and the medium resource persons also was preferred by the high resource player in the intrinsic motivation condition. Coalition conflict was intermediate in the mixed-motive conditions. In sum, it was demonstrated that coalition formation and interpersonal conflict are dependent upon the motivational determinants of group activity.     

Gradients of attraction as a function of the fit between social setting and stimulus person characteristics: Studies of the differentiation of attitude

Two experiments compared three alternative hypotheses concerning differences in attraction to a person across interaction settings: A compartmentalization hypothesis assumes that a person's (A's) intimate and nonintimate characteristics only affect attraction to him in intimate and nonintimate interactions, respectively, and that there is no generalization of attraction across levels of intimacy. An intimacy dominance hypothesis assumes that a person's intimacy-related characteristics determine attraction to him at all levels of interaction. Finally, an intimacy threshold hypothesis assumes that a person's intimacy-related characteristics become increasingly relevant to attraction as the intimacy of interaction increases, but that these characteristics need not influence attraction at nonintimate levels of interaction. Experiment 1 supported the compartmentalization hypothesis. Attraction to a formal teacher decreased as the intimacy of the anticipated setting increased, while attraction to an informal teacher increased with increasing setting intimacy. In Experiment 2, agreement on intimate topics promoted liking for a peer while no effect was found for agreement on superficial topics. This effect only emerged for intimate interaction settings, supporting the intimacy threshold hypothesis. High positive correlations between distance preference and attraction were obtained in Experiment 1, while analogous data obtained in Experiment 2 had less clear implications.