Dissertation
Subject specific effects of methylphenidate in rodent models of attention
Doctor of Philosophy (Ph.D.), Drexel University
Apr 2013
DOI:
https://doi.org/10.17918/00000620
Abstract
Methylphenidate (MPH) is the primary drug treatment of choice for ADHD. It is also frequently used off-label as a cognitive enhancer by up to 7% of all college students in this past year alone. Many working professionals such as military personnel, airline pilots, and health care professionals also use MPH illicitly to improve workplace performance over extended periods of work activity. Despite the frequency of its use, the efficacy of MPH to enhance cognition across individuals and in a variety of circumstances is not well characterized, much less characterization of the mechanism(s) by which MPH improves cognitive performance. We sought to better understand the efficacy of MPH's cognitive enhancing properties and the mechanism through which it acts by studying its effects in two different rodent models of attention. We found that MPH could enhance performance in a sustained attention task, but that its effects in this test were subject dependent. More specifically, MPH increased attention in low baseline performing rats but had no effect on high performing rats. We also found that MPH could selectively attenuate impairments in performance due to external factors such as introduction of a distractor or sleep deprivation in a subject dependent manner. Finally, MPH showed a similar subject specific effect in a different type of attention task where MPH increased behavioral flexibility in animals with poor flexibility but impaired performance in more flexible animals. Our results indicate that the effects of MPH are subject-specific and depend on the baseline level of performance. Low performance is generally improved by MPH, but high proficiency is not. In fact, high levels of performance may be impaired by MPH.
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Details
- Title
- Subject specific effects of methylphenidate in rodent models of attention
- Creators
- Richard Chu
- Contributors
- Barry D. Waterhouse (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xii, 173 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Medicine; Neurology; Drexel University
- Other Identifier
- 991014970227504721