2-[–3H]deoxyglucose uptake patterns in rats exploring a six-arm radial tunnel maze: Differences between experienced and nonexperienced rats.

In an automated tunnel maze rats were allowed to explore either a 6-arm radial configuration ("experienced") or an alley maze configuration ("nonexperienced"). The activity of control rats was restricted to the center of the maze. After 8 daily sessions and a 5-day break, catheters were implanted into the jugular vein. Two days later, 2-deoxyglucose was administered before both experimental groups were exposed to the 6-arm radial configuration. Nonexperienced rats differed from experienced rats in terms of efficiency of exploration, but not in locomotor activity. Compared with experienced animals, nonexperienced rats showed an increase in 2-deoxyglucose uptake in prefrontal and cingulate cortices and in mediodorsal and laterodorsal thalamic nuclei. Exposure of rats to familiar and unfamiliar maze patterns resulted in different patterns of brain metabolic activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On a Geometric Generalization of Entropy

A new approach to the notion of a probability space is proposed. A stochastically measurable space is equipped with a geometric structure by introducing distances between elementary events. The probabilistic proximity space (in the discrete case) is used to generalize the notion of entropy. Entropy thus geometrized is shown to preserve all the former properties and also to acquire a previously unknown useful quality. This opens new possibilities in the area of information disciplines.     

An interactive computer-based interface to support the discovery of individuals’ mental representations and preferences in decisions problems: An application to travel behavior

Growing emphasis is currently given in decision modeling on process data to capture behavioral mechanisms that ground decision-making processes. Nevertheless, advanced applications to elicit such data are still lacking. The Causal Network Elicitation Technique interview and card-game, both face-to-face interviews, are examples of a behavioral process method to obtain individuals’ decision-making by eliciting temporary mental representations of particular problems. However, to portray and model these representations into formal modeling approaches, such as Bayesian decision networks, an extensive set of parameters has to be gathered for each individual. Thus, data collection procedures for large sample groups can be costly and time consuming. This paper reports on the methodological conversion and enhancement of the existing elicitation methods into a computer-based interface that allows to not only uncover individuals’ mental representations but also to automate the generation of preference parameter elicitation questions. Results of such studies can be used to understand individuals’ constructs and beliefs with respect to decision alternatives, predict individuals’ decision behavior at a disaggregate level, and to assess behavioral changes due to differences in contexts and constraints.     

Brain trace elements and aging

Degenerative mechanisms involved in the aging process of the brain are to a certain extent counteracted by repair mechanisms. In both degenerative and recovery processes, trace elements are involved. The present study focused on the role of two minor (i.e., K and Ca) and six trace elements (i.e., Mn, Fe, Cu, Zn, Se and Rb) in the aging process. The elements were determined by PIXE in cerebral cortex and white matter, basal ganglia, brainstem and cerebellar cortex of 18 postmortem human brains, from persons without a history of neurologic or psychiatric disease who deceased between the age of 7 and 79. This age range allowed us to study the relationship between elemental concentrations and age. The most prominent findings were a concentration decrease for K and Rb and a concentration increase for the elements Ca, Fe, Zn and Se. The study supports recent findings that Ca and Fe are involved in brain degenerative processes initiated by oxygen free radicals, whereas Zn and Se are involved in immunological reactions counteracting the aging process.