No abstract

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 choice for a small, immediate over a large, delayed reinforcer. d-Amphetamine (1.0, 3.2 and 5.6 mg/kg) was administered to SHR and Wistar-Kyoto rats (WKY; their progenitor strain) before sessions of a choice task involving small, immediate and larger, delayed food reinforcers. As reported earlier, SHRs were more impulsive than WKYs (they preferred the smaller, immediate reinforcer). d-Amphetamine had no effect on preference for the SHRs, but increased choices for the small, immediate reinforcer for the WKYs at the 1.0 and 3.2 doses. Thus, d-amphetamine did not reduce impulsivity in the already impulsive SHRs, but did increase impulsivity in rats that were not already impulsive.

No abstract

Although adolescents are a group heavily targeted by the e-cigarette industry, research in cue-reactivity has not previously examined adolescents' behavioral and neural responses to e-cigarette advertising. This study addressed this gap through two experiments. In Experiment One, adult traditional cigarette smokers (n = 41) and non-smokers (n = 41) answered questions about e-cigarette and neutral advertising images. The 40 e-cigarette advertising images that most increased desire to use the product were matched to 40 neutral advertising images with similar content. In Experiment Two, the 80 advertising images selected in Experiment One were presented to adolescents (n = 30) during an functional magnetic resonance imaging brain scan. There was a range of traditional cigarette smoking across the sample with some adolescents engaging in daily smoking and others who had never smoked. Adolescents self-reported that viewing the e-cigarette advertising images increased their desire to smoke. Additionally, all participants regardless of smoking statuses showed significantly greater brain activation to e-cigarette advertisements in areas associated with cognitive control (left middle frontal gyrus), reward (right medial frontal gyrus), visual processing/attention (left lingual gyrus/fusiform gyrus, right inferior parietal lobule, left posterior cingulate, left angular gyrus) and memory (right parahippocampus, left insula). Further, an exploratory analysis showed that compared with age-matched non-smokers (n = 7), adolescent smokers (n = 7) displayed significantly greater neural activation to e-cigarette advertising images in the left inferior temporal gyrus/fusiform gyrus, compared with their responses to neutral advertising images. Overall, participants' brain responses to e-cigarette advertisements suggest a need to further investigate the long-run impact of e-cigarette advertising on adolescents.