Matching Items (3)
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- All Subjects: Inhibition
- Creators: Castaneda, Edward
- Creators: Hall, Deborah
- Member of: Theses and Dissertations
Description
Dopamine (DA) is a neurotransmitter involved in attention, goal oriented behavior, movement, reward learning, and short term and working memory. For the past four decades, mathematical and computational modeling approaches have been useful in DA research, and although every modeling approach has limitations, a model is an efficient way to generate and explore hypotheses. This work develops a model of DA dynamics in a representative, single DA neuron by integrating previous experimental, theoretical and computational research. The model consists of three compartments: the cytosol, the vesicles, and the extracellular space and forms the basis of a new mathematical paradigm for examining the dynamics of DA synthesis, storage, release and reuptake. The model can be driven by action potentials generated by any model of excitable membrane potential or even from experimentally induced depolarization voltage recordings. Here the model is forced by a previously published model of the excitable membrane of a mesencephalic DA neuron in order to study the biochemical processes involved in extracellular DA production. After demonstrating that the model exhibits realistic dynamics resembling those observed experimentally, the model is used to examine the functional changes in presynaptic mechanisms due to application of cocaine. Sensitivity analysis and numerical studies that focus on various possible mechanisms for the inhibition of DAT by cocaine provide insight for the complex interactions involved in DA dynamics. In particular, comparing numerical results for a mixed inhibition mechanism to those for competitive, non-competitive and uncompetitive inhibition mechanisms reveals many behavioral similarities for these different types of inhibition that depend on inhibition parameters and levels of cocaine. Placing experimental results within this context of mixed inhibition provides a possible explanation for the conflicting views of uptake inhibition mechanisms found in experimental neuroscience literature.
ContributorsTello-Bravo, David (Author) / Crook, Sharon M (Thesis advisor) / Greenwood, Priscilla E (Thesis advisor) / Baer, Steven M. (Committee member) / Castaneda, Edward (Committee member) / Castillo-Chavez, Carlos (Committee member) / Arizona State University (Publisher)
Created2012
Description
The purpose of this study, originally, was to contribute to the completion of a meta-analysis conducted by Mara Wierstra from the University of Virginia. Wierstra had requested individual participant data from two separate studies conducted in our lab: "Acute bouts of assisted cycling improves cognitive and upper extremity movement functions in adolescents with Down syndrome" and "Assisted Cycling Therapy (ACT) improves inhibition in adolescents with autism spectrum disorder." From the data requested, the participants were required to complete three separate tests (i.e., Tower of London, Trail Making Task and the Stroop Test). After compiling the data and sending it to her, we decided to conduct a small meta-analysis of our own, drawing connecting conclusions from the data from the two studies. We concluded that observationally our data suggest an advantage for ACT over voluntary cycling and no cycling across two separate populations (i.e., Autism Spectrum Disorder and Down syndrome), and across different measures of executive function (i.e., Stroop Test, Trail Making Test, and Tower of London). The data suggest that the ACT interventions may promote the upregulation of neurotropic factors leading to neurogenesis in the prefrontal cortex of the brain.
ContributorsParker, Cade Joseph (Author) / Ringenbach, Shannon (Thesis director) / Holzapfel, Simon (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Retrieving an item from memory can cause subsequent suppression of related items. This phenomenon, involving a procedure where participants retrieve category-exemplar pairs (e.g. FRUIT-orange), is known as Retrieval Induced Forgetting (RIF). Individuals who demonstrate greater amounts of RIF also exhibit greater working memory capacity (WMC). Reasoning ability is highly related to WMC, which may suggest that a similar relation exists between RIF and Reasoning ability. The goal of the present investigation was to examine this possibility. Rotation Span and a Letter Number task were used as indicators of WMC and a Cognitive Reflection Test was used to measure Reasoning ability. A significant RIF effect was found, but it did not significantly correlate with WMC or Reasoning ability. These results demonstrate the importance of designing a RIF task appropriately, selecting measures of Reasoning ability, and the theoretical accounts of the RIF effect. One possibility is that by not controlling for output interference, the obtained RIF effect cannot be reasoned to come from the executive control process as suggested by the inhibition account. Although this account is the chief explanation of the RIF effect, it has been challenged by alternative accounts and it remains unclear how the underlying mechanism of RIF is related to higher cognitive abilities.
ContributorsMaxwell, Joshua (Author) / Duran, Nicholas (Thesis advisor) / Hall, Deborah (Committee member) / Robles-Sotelo, Elias (Committee member) / Arizona State University (Publisher)
Created2016