Speed/Accuracy Trade-Off between the Habitual and the Goal-Directed Processes

Instrumental responses are hypothesized to be of two kinds: habitual and goal-directed, mediated by the sensorimotor and the associative cortico-basal ganglia circuits, respectively. The existence of the two heterogeneous associative learning mechanisms can be hypothesized to arise from the comparative advantages that they have at different stages of learning. In this paper, we assume that the goal-directed system is behaviourally flexible, but slow in choice selection. The habitual system, in contrast, is fast in responding, but inflexible in adapting its behavioural strategy to new conditions. Based on these assumptions and using the computational theory of reinforcement learning, we propose a normative model for arbitration between the two processes that makes an approximately optimal balance between search-time and accuracy in decision making. Behaviourally, the model can explain experimental evidence on behavioural sensitivity to outcome at the early stages of learning, but insensitivity at the later stages. It also explains that when two choices with equal incentive values are available concurrently, the behaviour remains outcome-sensitive, even after extensive training. Moreover, the model can explain choice reaction time variations during the course of learning, as well as the experimental observation that as the number of choices increases, the reaction time also increases. Neurobiologically, by assuming that phasic and tonic activities of midbrain dopamine neurons carry the reward prediction error and the average reward signals used by the model, respectively, the model predicts that whereas phasic dopamine indirectly affects behaviour through reinforcing stimulus-response associations, tonic dopamine can directly affect behaviour through manipulating the competition between the habitual and the goal-directed systems and thus, affect reaction time

Temporal abundance of Aedes aegypti in Manaus, Brazil, measured by two trap types for adult mosquitoes

A longitudinal study was conducted in Manaus, Brazil, to monitor changes of adult Aedes aegypti (L.) abundance. The objectives were to compare mosquito collections of two trap types, to characterise temporal changes of the mosquito population, to investigate the influence of meteorological variables on mosquito collections and to analyse the association between mosquito collections and dengue incidence. Mosquito monitoring was performed fortnightly using MosquiTRAPs (MQT) and BG-Sentinel (BGS) traps between December 2008-June 2010. The two traps revealed opposing temporal infestation patterns, with highest mosquito collections of MQTs during the dry season and highest collections of BGS during the rainy seasons. Several meteorological variables were significant predictors of mosquito collections in the BGS. The best predictor was the relative humidity, lagged two weeks (in a positive relationship). For MQT, only the number of rainy days in the previous week was significant (in a negative relationship). The correlation between monthly dengue incidence and mosquito abundance in BGS and MQT was moderately positive and negative, respectively. Catches of BGS traps reflected better the dynamic of dengue incidence. The findings help to understand the effects of meteorological variables on mosquito infestation indices of two different traps for adult dengue vectors in Manaus

Avaliação da atenção básica pela ótica político-institucional e da organização da atenção com ênfase na integralidade Political, institutional, and organizational evaluation of primary health care with an emphasis on comprehensiveness

Este artigo apresenta parte dos dados de uma avaliação da Atenção Básica, implementada como parte de uma pesquisa com financiamento do Ministério da Saúde durante o ano de 2005. Trinta e um municípios, dos estados de Minas Gerais e Espírito Santo, Brasil, formaram a amostra do estudo. Dados coletados com base em métodos qualitativos (entrevistas e análise de documentos) foram sintetizados com a produção de um conjunto de variáveis categoriais. A distribuição dos diversos valores assumidos pelas variáveis nos diferentes municípios são apresentadas. Essas variáveis foram submetidas à análise de correspondência, que mostrou sua validade interna. Adicionalmente, observações sobre aspectos relevantes do campo são apresentados. Em conclusão, a avaliação mostra avanços da estratégia de saúde na família, com importantes contribuições do Projeto de Expansão e Consolidação do Saúde da Família, embora obstáculos consideráveis ainda permaneçam, em particular no que diz respeito à força de trabalho das estratégias de saúde na família e na utilização local das informações produzidas.<br>This article presents part of the data from an evaluation of primary care, implemented as part of research funded by the Brazilian Ministry of Health in 2005. Thirty-one municipalities from the States of Minas Gerais and Espírito Santo comprised the study sample. Data collected with qualitative methods (interviews and documents) were summarized, with the production of a set of categorical variables. The article presents the distribution of values for the variables by municipality. The variables were submitted to correspondence analysis, which showed their internal validity. The article also provides observations on relevant aspects of the field. In conclusion, the evaluation demonstrates advances in the Family Health Strategy in Brazil, with important contributions to the Project for Expansion and Consolidation of the Family Health Strategy, despite persistent obstacles, particularly related to human resources in the family health strategies and local use of the data produced