Neuronal NT-3 Is not Required For Synaptic Transmission or Long-Term Potentiation in Area CA1 of the Adult Rat Hippocampus

Neurotrophic factors, including BDNF and NT-3, have been implicated in the regulation of synaptic transmission and plasticity. Previous attempts to analyze synaptic transmission and plasticity in mice lacking the NT-3 gene have been hampered by the early death of the NT-3 homozygous knockout animals. We have bypassed this problem by examining synaptic transmission in mice in which the NT-3 gene is deleted in neurons later in development, by crossing animals expressing the CRE recombinase driven by the synapsin I promoter to animals in which the NT-3 gene is floxed. We conducted blind field potential recordings at the Schaffer collateral–CA1 synapse in hippocampal slices from homozygous knockout and wild-type mice. We examined the following indices of synaptic transmission: (1) input-output relationship; (2) paired-pulse facilitation; (3) post-tetanic potentiation; and (4) long-term potentiation: induced by two different protocols: (a) two trains of 100-Hz stimulation and (b) theta burst stimulation. We found no difference between the knockout and wild-type mice in any of the above measurements. These results suggest that neuronal NT-3 does not play an essential role in normal synaptic transmission and some forms of plasticity in the mouse hippocampus.     

An exploratory study on the development of beliefs about symptoms as signals of arterial hypertension

An exploratory study on the development of beliefs about symptoms as signals of arterial hypertension. In spite of hypertension is known as an asymptomatic health problem, most of the people with such a diagnosis are convinced of experiencing very specific symptoms associated to specific changes in blood pressure (BP). In addition, such beliefs may affect treatment adherence. Previous studies have shown that hypertensive patients use the information they considered right about BP symptoms to regulate the type of decisions they follow in adhering to treatment. The aim of this study is to explore specific variables related with the formation of beliefs about symptoms in a sample of 171 hypertensive patients. Results show that 81,3% of the patients perceived specific symptoms related to changes in hypertension as well as that variables related with the development of these beliefs were mostly: (1) the presence of symptoms during the diagnosis process, (2) the occurrence of hypertensive crisis, and (3) the information provided by others concerning the relationships between symptoms and BP changes. The importance of paying attention to the beliefs of specific symptoms as well as to the circumstances related with the formation process of such beliefs is discussed.     

Subtypes of drug-addicts in treatment: empirical support for a distinction between Type A and Type B

This study examines the possibility of replicating and generalizing a multidimensional typology of drug-addicts by means of the evaluation of 320 participants who were receiving outpatient treatment for their problem of addiction. A two-stage cluster analysis was performed, revealing the existence of two typologies of consumers, called type A and Type B. The participants classified as Type B showed various indicators of chronicity (higher mean age, higher unemployment rate), more severity of their problem of drug consumption and of medical aspects, employment support, legal, family/social and psychiatric problems in comparison with Type A. Participants from the latter group reported active employment as their main source of income and they had consumed drugs for fewer years. However, they presented more severity associated with alcohol consumption. In view of these data, Type A is called functional drug-addict and Type B chronic drug-addict. Once the groups of drug-addicts were delimited, a more specific characterization was made, taking seven problem areas into account: medical, employment support, alcohol, drugs, legal, family/social, and psychiatric areas. As a general conclusion, more psychosocial severity was observed in Type B as compared with Type A. Lastly, the implications and usefulness of grouping drug-addicts into typologies is discussed.     

Alpha2A-adrenoceptor stimulation improves prefrontal cortical regulation of behavior through inhibition of cAMP signaling in aging animals

The working-memory functions of the prefrontal cortex (PFC) are improved by stimulation of postsynaptic, alpha2A-adrenoceptors, especially in aged animals with PFC cognitive deficits. Thus, the alpha2A-adrenoceptor agonist, guanfacine, greatly improves working-memory performance in monkeys and rats following systemic administration or intra-PFC infusion. Alpha2A-adrenoceptors are generally coupled to Gi, which can inhibit adenylyl cyclases and reduce the production of cAMP. However, no study has directly examined whether the working-memory enhancement observed with guanfacine or other alpha2A-adrenoceptor agonists results from cAMP inhibition. The current study confirmed this hypothesis in both rats and monkeys, showing that treatments that increase cAMP-mediated signaling block guanfacine's beneficial effects. In aged rats, guanfacine was infused directly into the prelimbic PFC and was challenged with co-infusions of the cAMP analog, Sp-cAMPS. In aging monkeys, systemically administered guanfacine was challenged with the phosphodiesterase 4 inhibitor, rolipram, using intramuscular doses known to have no effect on their own. In both studies, agents that mimicked the actions of cAMP (rats) or increased endogenous cAMP (monkeys) completely blocked the enhancing effects of guanfacine on working-memory performance. These results are consistent with alpha2A-adrenoceptor stimulation enhancing PFC working-memory function via inhibition of cAMP-mediated signaling.     

New measure o f perceived motorcompetence for children ages 4 to 6 years

The purpose of this study was to develop and validate a test for the assessment of perceived motor competence in young children ages 4 to 6 years old. The structure of the Children's Perception of Motor Competence Scale was analyzed through exploratory and confirmatory factor analysis with 495 children between 4 and 6 years of age. A second-order model was selected and consisted of one scale of Perceived General Motor Competence and two subscales, Perceived Gross Motor Competence and Perceived Fine Motor Competence. The number of items was 22. This test showed acceptable internal reliability: global scale (alpha = .81), Perceived Gross Motor Competence (alpha = .80), and Perceived Fine Motor Competence (alpha = .65). Children manifested accuracy in the assessment of the competence. Perceived motor competence was related to actual motor competence as measured by the Movement ABC Test and by an observational scale used by Physical Education teachers. There were no sex differences. The Children's Perception of Motor Competence Scale could be considered an interesting assessment test for identifying current self-perceptions of motor competence in young children.     

Hand effects on mentally simulated reaching

Within the area of simulated (imagined) versus actual movement research, investigators have discovered that mentally simulated movements, like real actions, are controlled primarily by the hemispheres contralateral to the simulated limb. Furthermore, evidence points to a left-brain advantage for accuracy of simulated movements. With this information it could be suggested that, compared to left-handers, most right-handers would have an advantage. To test this hypothesis, strong right- and left-handers were compared on judgments of perceived reachability to visual targets lasting 150 ms in multiple locations of midline, right- and left-visual field (RVF/LVF). In reference to within group responses, we found no hemispheric or hand use advantage for right-handers. Although left-handers revealed no hemispheric advantage, there was a significant hand effect, favoring the non-dominant limb, most notably in LVF. This finding is explained in regard to a possible interference effect for left-handers, not shown for right-handers. Overall, left-handers displayed significantly more errors across hemispace. Therefore, it appears that when comparing hand groups, a left-hemisphere advantage favoring right-handers is plausible.     

Sequence learning under dual-task conditions: alternatives to a resource-based account

In two experiments with the serial reaction-time task, participants were presented with deterministic or probabilistic sequences under single- or dual-task conditions. Experiment 1 showed that learning of a probabilistic structure was not impaired over a first session by performing a counting task, but that such an interference arose over a second session, when the knowledge was tested under single-task conditions. In contrast, the effects of the secondary task arose earlier for participants exposed to deterministic sequences. This difference between deterministic and probabilistic sequences disappeared in Experiment 2, where the counting task was performed on tones associated to the locations. Comparisons between sessions indicated that the secondary task affected not only the expression but also the acquisition of sequence learning, and that greater interference was observed in those conditions that yielded more explicit knowledge. These results suggest that the effects of a dual task on the measures of implicit sequence learning may be partly due to the intrusion of explicit knowledge and partly due to the disruption of the sequence produced by the inclusion of random events.     

The Cosmopolitan Imperative: Global Justice Through Accountable Integration

Cosmopolitan political theorists hold that our obligations to distribute resources to others do not halt at state borders, but most do not advocate a restructuring of the global system to achieve their distributive aims. This article argues that promoting democratically accountable economic and political integration between states would be the most effective way to enable cosmopolitan, or routine, tax-financed, trans-state distributions. Movement toward a more integrated global system should encourage the view that larger sets of persons have interests in common that should be protected and promoted in common. Democratically accountable integration also should enable those within less-affluent states to more vigorously press trans-state distributive claims. The still-evolving E.U. is examined as a partial model for the integrated alternative in other geographic regions, as well as, in the much longer term, for some form of democratic global government capable of ensuring that any person born anywhere would have access to adequate resources and life opportunities.A version of this paper was presented at the global justice mini-conference at the American Philosophical Association (Pacific Division) annual meeting, Pasadena, California, 26–29 March 2004. Some of the arguments in this article were introduced in Luis Cabrera, Political Theory of Global Justice: A Cosmopolitan Case for the World State (London: Routledge, 2004), Chapter 4. They have been revised and further developed for this article. I would like to thank for their generous comments Jamie Mayerfeld, James A. Caporaso and Mika LaVaque-Manty.     

Alcohol and Drug Use, and Depression Among Hispanic Men in Early Adulthood

Community research and clinical practice have shown that alcohol and drug use and depression are interrelated. Among Hispanics, acculturation may play a role in these relationships. To investigate these relationships as well as alcohol-related problems, we interviewed 288 Puerto Rican, Dominican, and Colombian men in early adulthood. No significant differences emerged in the proportions of abstainers across the three groups. Colombians drank significantly more frequently and had more alcohol-related problems than Dominicans. Dominicans were at least risk for and least likely to have alcohol-related problems. Puerto Ricans were much more likely to use drugs than the other Hispanic men. Drug use was associated with an increased likelihood of heavy drinking which, in turn, increased the risk of drug use and depression. Acculturation decreased the risk of drug use. Results are discussed in terms of implications for community psychology research and interventions.     

Attitudes Toward Affirmative Action in the United States and Canada

Attitudes toward affirmative action programs were investigated using a U.S. sample, an English speaking Canadian sample, and a French speaking Canadian sample. Results indicate that cultural influences in the form of individualism-collectivism were small but that ethnic and linguistic memberships were major influences on attitudes toward those programs.