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The spontaneously hypertensive rat (SHR) has been shown to exhibit three of the behavioral characteristics of attention-deficit/hyperactivity disorder: hyperactivity, attention deficit and impulsivity. This study used SHRs and a control strain to assess the effects of the commonly prescribed psychomotor stimulant, d-amphetamine, on impulsivity, defined as(More)
The spontaneously hypertensive rat (SHR) has been studied extensively as a purported rodent model of attention-deficit/hyperactivity disorder (ADHD). Because ADHD in humans is partially defined by marked impulsivity, SHRs, if a valid model of ADHD, ought to behave more impulsively than their normotensive parent strain, Wistar Kyoto (WKY). This prediction(More)
The spontaneously hypertensive rat (SHR) has been shown to exhibit behavioral characteristics analogous to those exhibited by humans diagnosed with attention-deficit/hyperactivity disorder (ADHD). The present study was conducted to further evaluate the validity of the SHR model of ADHD by characterizing learning of a novel response under conditions of(More)
Three experiments investigated the effects of immediate and delayed postsession feeding on progressive-ratio and variable-interval schedule performance in rats. During Experiments 1 and 2, immediate postsession feeding decreased the breakpoint, or largest completed ratio, under progressive-ratio schedules. Experiment 3 was conducted to extend the results of(More)
Pramipexole (PPX) is a high-affinity D2-like dopamine receptor agonist, used in the treatment of Parkinson's disease (PD) and restless leg syndrome. Recent evidence indicates that PPX increases the risk of problem gambling and impulse-control disorders in vulnerable patients. Although the molecular bases of these complications remain unclear, several(More)
Central Place and Central Flow Theory are geographic principles explaining why and how cities develop across large regional spaces. Central Place Theory postulates that cities self-organize into a spatial hierarchy were small numbers of very large 'Central Places' support numerous surrounding and less developed 'Low Places', while 'Middle Places' develop at(More)