Use of NSE/PS2m-transgenic mice in the study of the protective effect of exercise on Alzheimer's disease

In its late stage, Alzheimer's disease results in progressive muscle weakness in the arms and legs. The aim of this study was to determine whether mice expressing the skeletal muscle-specific mutant PS2 gene (a model of Alzheimer's disease) are a useful experimental system to study the protective effect of exercise on A beta-42 reduction, improvement of behavioural function and changes in metabolic parameters. With this aim in mind, the transgenic mice were subjected to treadmill exercise for 3 months. The results showed that in transgenic mice, but not in normal mice, treadmill exercise resulted in a reduction of A beta-42 deposits and an improvement in behavioural function, thereby restoring normal concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglyceride. Thus, exercise may represent a practical therapeutic strategy for use with human patients with Alzheimer's disease.     

Waiting to decide helps in the face of probabilistic uncertainty but not delay uncertainty

A first-person shooter video game was adapted for the study of causal decision making within dynamic environments. Participants chose which of three potential targets in each of 21 groups was producing distal explosions. The source of the explosion effect varied in the delay between the firing of its weapon and its effect (0.0, 0.5, 1.0, and 2.0 s), the probability that the weapon caused the effect (50%, 75%, and 100%), and the occurrence of auditory events that filled the delay. In Experiment 1, participants’ choice accuracy was highest with short delays but was not affected by probability; participants often compensated for lower probability by increasing their latencies, and thus the number of outcomes sampled. In Experiment 2, a broad range of delays (0–2 s) and probabilities (20%–100%) were randomly sampled for each cause; the results largely replicated those of the prior experiment. The experiments demonstrate people’s ability to successfully modulate their environmental sampling in the face of uncertainty due to lower cause–effect probabilities, but not in the presence of longer cause–effect delays.