“
“Although several molecular and genetic manipulations may produce hyperactive animals, hyperactivity alone is insufficient for the animal to qualify as a model of ADHD. Based on a wider range of criteria behavioral, genetic and neurobiological – the spontaneously learn more hypertensive rat (SHR)

obtained from Charles River, Germany (SHR/NCrl) at present constitutes the best validated animal model of ADHD combined subtype (ADHD-C), and the Wistar Kyoto substrain obtained from Harlan, UK (WKY/NHsd) is its most appropriate control. Although other rat strains may behave like WKY/NHsd rats, genetic results indicate significant differences when compared to the WKY/NHsd substrain, making them less suitable controls for the SHR/NCrl, The use of WKY/NCrl, outbred Wistar, Sprague Dawley or other rat strains as controls for SHRs may produce spurious neurobiological differences. Consequently data may be mis, interpreted if insufficient care is taken in the selection of the control group. It appears likely that the use of different control strains may underlie some of the discrepancies

in results and interpretations in studies involving the SHR and WKY. Finally, we argue that WKY rats obtained from Charles River, Germany (WKY/NCrl) provide a promising model for the predominantly inattentive subtype of ADHD (ADHD-PI); in this case also the WKY/NHsd substrain should be used as control. (C) 2009 Elsevier Ltd. All rights reserved.”
“We compared the performance

of Bayesian learning strategies and approximations to such strategies, which are far less computationally demanding, in a setting requiring Selleck FRAX597 individuals to make binary decisions based on experience. Extending Bayesian updating schemes, we compared the different strategies while allowing for various implementations of memory and knowledge about the environment. The dynamics of the observable variables was modeled through basic probability distributions and convolution. This theoretical framework was applied to the problem of male fruit flies who have to decide which females they should www.selleck.cn/products/MS-275.html court. Computer simulations indicated that, for most parameter values, approximations to the Bayesian strategy performed as well as the full Bayesian one. The linear approximation, reminiscent of the linear operator, was notably successful, and, without innate knowledge, the only successful learning strategy. Besides being less demanding in computation and thus realistic for small brains, the linear approximation was also successful at limited memory, which would translate into robustness in rapidly changing environments. Knowledge about the environment boosted the performance of the various learning strategies with maximal performance at large utilization of memory. Only for limited memory capacities, intermediate knowledge was most successful.