Matching Items (4)
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- All Subjects: Rats
- Creators: Neisewander, Janet L
- Creators: Phillips, Elizabeth Capaldi
Description
Smoking remains the leading cause of preventable death in the United States, and early initiation is associated with greater difficulty quitting. Among adolescent smokers, those with attention-deficit hyperactivity disorder (ADHD), characterized by difficulties associated with impulsivity, hyperactivity, and inattention, smoke at nearly twice the rate of their peers. Although cigarette smoking is highly addictive, nicotine is a relatively weak primary reinforcer, spurring research on other potential targets that may maintain smoking, including the potential benefits of nicotine on attention, inhibition, and reinforcer efficacy. The present study employs the most prevalent rodent model of ADHD, the spontaneously hypertensive rat (SHR) and its control comparison Wistar Kyoto (WKY) to examine the effects of acute and chronic subcutaneous nicotine injections on performance in three operant response inhibition paradigms. Functional activation in select regions of the prefrontal cortex and striatum was also explored. Acute (0.1, 0.3, 0.6 mg/kg) and chronic (0.3 mg/kg) nicotine increased impulsive responding regardless of strain, dose, or operant schedule. Dose-dependent decreases in latency to initiate the task were also observed. SHR receiving daily nicotine injections showed less activation in the nucleus accumbens shell compared to saline controls. Despite close similarities, one of the three operant tasks did not detect response inhibition deficits in SHR relative to WKY. A closer examination of these tasks may highlight critical components involved in the amelioration of response inhibition deficits.
ContributorsMazur, Gabriel Joseph (Author) / Sanabria, Federico (Thesis advisor) / Killeen, Peter R (Committee member) / Neisewander, Janet L (Committee member) / Wynne, Clive DL (Committee member) / Arizona State University (Publisher)
Created2014
Description
Nicotine is thought to underlie the reinforcing and dependence-producing effects of tobacco-containing products. Nicotine supports self-administration in rodents, although measures of its reinforcing effects are often confounded by procedures that are used to facilitate acquisition, such as food restriction, prior reinforcement training, or response-contingent co-delivery of a naturally reinforcing light. This study examined whether rats acquire nicotine self-administration in the absence of these facilitators. A new mathematical modeling procedure was used to define the criterion for acquisition and to determine dose-dependent differences in rate and asymptote levels of intake. Rats were trained across 20 daily 2-h sessions occurring 6 days/week in chambers equipped with active and inactive levers. Each active lever press resulted in nicotine reinforcement (0, 0.015, 0.03, 0.06 mg/kg, IV) and retraction of both levers for a 20-s time out, whereas inactive lever presses had no consequences. Acquisition was defined by the best fit of a logistic function (i.e., S-shaped) versus a constant function (i.e., flat line) for reinforcers obtained across sessions using a corrected Akaike information criterion (AICc) as a model selection tool. The results showed an inverted-U shaped function for dose in relation to the percentage of animals that acquired nicotine self-administration, with 46% acquiring at 0.015 mg/kg, 73% at 0.03 mg/kg, and 58% at 0.06 mg/kg. All saline rats failed to acquire as expected. For rats that acquired nicotine self-administration, multiple model comparisons demonstrated that the asymptote (highest number of reinforcers/session) and half learning point (h; session during which half the assymptote had been achieved) were justified as free parameters of the reinforcers/session function, indicating that these parameters vary with nicotine dose. Asymptote exhibited an inverted U-shaped function across doses and half learning point exhibited a negative relationship to dose (i.e., the higher the dose the fewer sessions to reach h). These findings suggest that some rats acquire nicotine self-administration without using procedures that confound measures of acquisition rate. Furthermore, the modeling approach provides a new way of defining acquisition of drug self-administration that takes advantage of using all data generated from individual subjects and is less arbitrary than some criteria that are currently used.
ContributorsCole, Natalie (Author) / Neisewander, Janet L (Thesis advisor) / Sanabria, Federico (Thesis advisor) / Bimonte-Nelson, Heather A. (Committee member) / Olive, Michael F (Committee member) / Arizona State University (Publisher)
Created2011
Description
The purpose of the present study was to evaluate if the size of food items is an important dimension of food incentive in rats. The experiment involved training rats on a T-maze with 1, 45 mg pellet and 7, 5 mg pellets in one alternative and 8, 10 mg pellets in the other alternative. Results from this study indicated that the rats showed preference for the alternative that contained the 1, 45 mg pellet surrounded by 7, 5 mg pellets. Thus, rats preferred the food set that contained the larger sized food unit to an equicaloric food set with only smaller sized food units. In regards to running speed, no significant differences were found for either alternative of food. Results from this study indicated that the apparent size of an item could be a factor in the incentive value of food and perhaps, rats used size as a heuristic, placing a higher incentive value on the food set that contained the larger sized food unit than one containing only smaller sized food units.
ContributorsAnderson, Ashley Linnea (Author) / Phillips, Elizabeth Capaldi (Thesis director) / Presson, Clark (Committee member) / Cohen, Adam (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2013-05
Description
Previous studies showed that rats preferred and also ran faster for multiple pellets than a single pellet of food. Here, we manipulated the rewarding effects of surface area occupied by food pellets on preference and running speed of rats trained on a T-maze. Twenty-two male adult Sprague-Dawley rats were trained to prefer one T-maze arm containing 30 food pellets scattered and the other arm with 30 pellets clustered. There was a significant preference for clustered food pieces over the scattered ones. The choice of the clustered food pieces may be explained by the optimal foraging theory to maximize energy gain. Therefore, larger surface area occupied by food pieces may be less rewarding when unnecessary energy is expended.
ContributorsTran, Alexander Chauson (Author) / Phillips, Elizabeth Capaldi (Thesis director) / Jacobs, Mark (Committee member) / Bajaj, Devina (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor)
Created2013-05