The role of observing and attention in establishing stimulus control.

Early theorists (Skinner, Spence) interpreted discrimination learning in terms of the strengthening of the response to one stimulus and its weakening to the other. But this analysis does not account for the increasing independence of the two performances as training continues or for increases in control by dimensions of a stimulus other than the one used in training. Correlation of stimuli with different densities of reinforcement produces an increase in the behavior necessary to observe them, and greater observing of and attending to the relevant stimuli may account for the increase in control by these stimuli. The observing analysis also encompasses errorless training, and the selective nature of observing explains the feature-positive effect and the relatively shallow gradients of generalization generated by negative discriminative stimuli. The effectiveness of the observing analysis in handling these special cases adds to the converging lines of evidence supporting its integrative power and thus its validity.     

Neuropsychological and neurophysiological effects of strengthening exercise for early dementia: A pilot study

ABSTRACT

Research demonstrates a positive effect of aerobic exercise on cognitive functioning in older adults. Unfortunately, aerobic exercise is often contraindicated for older adults due to cardiovascular and functional limitations. Low-intensity strengthening exercise may offer a practical alternative, but the neuropsychological benefits and potential neurophysiological mechanisms are less well understood. The current study evaluated the effects of a 10-week strengthening exercise intervention on cognitive functioning and EEG in a sample of 13 older adults with early dementia, and 9 normative controls. Results revealed beneficial effects of strengthening exercise on verbal memory coupled with frontal beta and delta power asymmetries and N200 amplitude asymmetry. Results point to increased cognitive efficiency following 10 weeks of strengthening exercise. The findings suggest it is feasible to conduct a strengthening intervention with early dementia patients, and to gather neuropsychological and neurophysiological data to evaluate outcomes. Strengthening exercise may serve as a useful alternative to aerobic exercise.     

Combinatorial data analysis: Association and partial association

A combinatorial data analysis strategy is reviewed that is designed to compare two arbitrary measures of proximity defined between the objects from some set. Based on a particular cross-product definition of correspondence between these two numerically specified notions of proximity (typically represented in the form of matrices), extensions are then pursued to indices of partial association that relate the observed pattern of correspondence between the first two proximity measures to a third. The attendant issues of index normalization and significance testing are discussed; the latter is approached through a simple randomization model implemented either through a Monte Carlo procedure or distributional approximations based on the first three moments. Applications of the original comparison strategy and its extensions to partial association may be developed for a variety of methodological and substantive tasks. Besides rank correlation, we emphasize the topics of spatial autocorrelation for one variable and spatial association between two and mention the connection to the usual randomization approach for one-way analysis-of-variance.     

临床方法依然是神经内科医师最重要的诊断法宝

通过7例疑难、危重患者的诊治过程说明临床方法的重要性,在神经科疾病研究中尤为突出。忽视细致的病史采集和体查,常导致了诊疗的失误;面对种目繁多的检查,更需要以临床方法选择之;临床逻辑思维能力非常重要,正确的临床思维出新知。在实验室检查方法越来越多的今天,临床方法是神经内科医师最重要、方便、快捷、有效的诊断法宝,具有不可替代性。     

Diferencias individuales en cognición: una nueva aproximación a la inteligencia

RESUMEN

El hecho de las diferencias individuales en el funcionamiento mental es una realidad. Su amplitud y naturaleza tiene unas consecuencias tan importantes en nuestra cultura que hace que la sociedad demande una forma de medir la inteligencia. No obstante algunos psicólogos opinan que los tests de inteligencia son un instrumento de medida que no representa adecuadamente un modelo formal de la dinámica de los procesos de pensamiento. Este artículo consiste en una serie de argumentos teóricos y empíricos contra la separación de los tests y las teorías cognitivas. Se piensa, en este artículo, que se pueden producir substanciales beneficios del acercamiento entre el psicólogo experimental y el psicómetra; los datos disponibles indican cómo se puede producir este acercamiento.     

Medición de la visualización espacial mediante tests informatizados

Resumen

Desde la corriente cognitiva que impulsa la construcción de tests polifacéticos, se han diseñado cuatro tests informatizados de Visualización Espacial empleando tareas similares a las clásicas de doblado de papel, desarrollo de superficies, recuento de bloques y rompecabezas. En una muestra de 501 alumnos universitarios se analizan los efectos de las facetas sobre los tiempos de reacción y la precisión. Como se esperaba, sólo algunas condiciones de las tareas implican el uso de las transformaciones mentales definitorias del constructo de Visualización. Se enfatiza la importancia de estos resultados para la construcción y validación de los tests espaciales.     

What cognitive abilities are involved in trail-making performance?

The cognitive abilities involved in the Connections (Salthouse, et al., 2000) version of the trail making test were investigated by administering the test, along with a battery of cognitive tests and tests of complex span and updating conceptualizations of working memory, to a sample of over 3600 adults. The results indicate that this variant of the trail making test largely reflects individual differences in speed and fluid cognitive abilities, with the relative contributions of the two abilities varying according to particular measure of performance considered (e.g., difference, ratio, or residual). Relations of age on trail making performance were also examined. Although strong age differences were evident in the Connections and working memory measures, with both sets of variables there was nearly complete overlap of the age differences with individual differences in speed and fluid cognitive abilities.     

Constructing the exact significance level for a person fit statistic

This paper uses an extension of the network algorithm originally introduced by Mehta and Patel to construct exact tail probabilities for testing the general hypothesis that item responses are distributed according to the Rasch model. By assuming that item difficulties are known, the algorithm is applicable to the statistical tests either given the maximum likelihood ability estimate or conditioned on the total score. A simulation study indicates that the network algorithm is an efficient tool for computing the significance level of a person fit statistic based on test lengths of 30 items or less.     

Cognitive function after open-heart surgery: Are postoperative neuropsychological deficits caused by cardiopulmonary bypass?

Despite the many technological developments in arterial perfusion and cardiac surgical procedures, open-heart surgery is still believed to pose a significant risk for cerebral injury. There are several potential causes of brain damage during open-heart surgery, including prolonged or severe arterial hypotension, as well as emboli emanating from the cardiopulmonary bypass circuit or the operative field. This article reviews the available neuropsychological studies of outcome following cardiac valve replacement and coronary artery bypass grafting. Because both procedures are life-saving operations, the research in this area has been quasi-experimental and fraught with methodological problems. Nonetheless, the findings converge to suggest that cognitive dysfunction occurs after open-heart surgery, and that the deficits are attributable, at least in part, to factors specific to the operation or to the patient being maintained on cardiopulmonary bypass. Preliminary findings suggest that embolization is the primary cause of perioperative deficits in uncomplicated operations. Studies have also consistently found preoperative deficits in this population, suggesting that neuropsychological dysfunction is caused by severe chronic cardiac disease as well as open-heart surgery.