Examining patterns suggestive of acquisition during functional analyses: A consecutive controlled series of 116 cases

The functional analysis approach described by Iwata et al. (1982/1994) has been used widely to determine the variables evoking and maintaining challenging behavior. However, one potential concern with conducting functional analyses is that repeated exposure to contingencies may induce a novel functional relation. To examine the likelihood of these potential iatrogenic effects, we evaluated social test conditions of the functional analysis for 116 participants and searched for patterns of responding indicative of acquisition. Patterns suggestive of acquisition occurred in 13.70% of tangible reinforcement conditions; however, the prevalence was only slightly lower in the attention condition (8.75%). Much lower prevalence was observed for the escape condition (2.13%). When grouped by quotient score, a pattern of acquisition was just as likely to be observed in the attention condition as in the tangible condition. Additionally, patterns indicative of acquisition were no more likely to be observed with participants who emitted automatically reinforced challenging behavior.     

Sex Differences in Risk Taking: Repeated Sessions on a Computer-Simulated Task

Two experiments were conducted to investigate sex differences in risktaking behavior on a computer-generated and controlled task. Male and female subjects faced a video display of simulated mine fields with varying numbers and patterns of dots representing mines in the fields. In Experiment 1, they estimated the probability that a tank might successfully cross 100 mine fields when starting from an unknown point below each field. This was followed by the risk-taking task in which they decided whether to send a tank across each of the fields. The participants were tested on the risk-taking task once in Experiment 1 and over four separate sessions in Experiment 2. Scores, based on decision outcomes, and decision latencies were recorded. No significant sex differences were found in the participants' ability to estimate probabilities or in their total scores for decisions made on the risk-taking task. In low probability-of-success situations, women initially took greater risks than men but took longer to make their decisions; in all subsequent sessions, this pattern was reversed, with men taking greater risks and a longer time to make decisions. The findings support the growing body of evidence that men are more inclined to take risks than women in a variety of situations, indicate the importance of obtaining data over repeated sessions when investigating sex differences in risk taking, and demonstrate that computer-simulated tasks can provide a valid means for laboratory studies of sex differences in risk taking.     

Extent of food restriction affects probability but not delay-based decision-making

Rodent studies on decision-making often use food rewards and food-restrict subjects in order to motivate performance. However, food restriction has widespread effects on brain and behavior, which depend on factors including extent of restriction and feeding schedule. These factors are well recognized for their effects on motivation, but may also cause effects on decision-making independent of motivation. We examined how the degree of weight-based food restriction in rats influenced decision-making on the probability and delay discounting tasks. Additionally, we examined how the method of food restriction (consistent amount vs. time constrained feeding schedule) influenced decision-making. Our results showed that the degree of weight-based food restriction significantly altered probability, but not delay discounting, and that these effects were not entirely explainable by differences in motivation. Additionally, the method of food restriction did not significantly influence discounting when animals were within the same range of weight-based restriction. Together, our findings suggest that the degree of food restriction may modulate the neural circuitry responsible for selective aspects of decision-making related to probability. Further, these data support the need for tight control and reporting of weight and feeding in studies relying on food restriction, and suggest that the effects of food restriction may be broader than previously considered.     

常见肺栓塞评分方法及临床应用

肺栓塞评分方法是国际上肺栓塞诊断策略的重要基础。本文简要介绍国际上常用肺栓塞评分方法,即Wells法、Geneva法、Geneva改良法、Pisa法和Claudia法,并评价和比较这些方法在临床上的应用,建议建立并规范使用适合我国国情的肺栓塞评分方法。