Senior Theses: 2007-2008
Characterization of the afferent gustatory responsiveness of the chorda tympani nerve to tastants with and without linoleic acid in obesity-prone and obesity-resistant rat strains.
an Honors Thesis by Kimberly Smith
Faculty advisor: David Pittman, Ph.D.
Previous research has shown that obesity-resistant, S5B rats differentially prefer carbohydrate diets compared to high-fat diet preference of the obesity-prone, OM rats. Furthermore, following a conditioned taste aversion, OM rats appear to be more sensitive in detecting fatty acids. In vitro recordings from taste receptor cells suggest further strain differences such that fatty acids appear to produce more depolarization in the S5B rats than OM rats; however, in vivo gustatory signaling has not been examined in either strain. This study characterized afferent gustatory responses of the whole chorda tympani nerve in these two strains of rat using an array of salt, bitter, umami, and sweet taste stimuli with and without the presence of a fatty acid. The strains showed similar neural responsiveness across the tastant categories. The addition of 200 µM linoleic acid did not consistently enhance or suppress the neural responses to the tastants. The S5B strain demonstrated greater differences in neural responses between the three sweet stimuli compared to the OM strain which showed similar responsiveness across the sweet stimuli. The difference in the neural responsiveness to sweet stimuli may underlie the dietary preference for carbohydrates observed in the S5B strain.
The relationship between student engaged learning, development, and health outcomes
an Honors Thesis by Mary Catherine McClain
Faculty advisor: John Lefebvre, Ph.D.
The purpose of this paper is to examine the potential for engaged learning to produce positive impacts on student learning, alcohol use, civic responsibility, and overall well-being across time. Educators have widely accepted and recognized that student engagement in educational activities inside and outside the classroom promotes higher levels of student learning and personal development. However, relatively few studies have explored the link between student engagement, student health, and overall well-being, and even fewer studies have examined engagement at the course level. The present paper has two primary purposes. One purpose is to provide a review of previous research findings, programs, and knowledge about the effects of student engagement. The second purpose is to present findings based on two current empirical research designs. Specifically, this paper examines and discusses a multi-method approach that was used for collecting data to assess the contributions of engaged learning to enhancing students’ academic development, civic responsibility, social development, and overall wellbeing. Results from the first study suggest that engaged learning can significantly enhance student health and well-being. Findings from the second study indicate that there is incongruence between practices faculty value and the frequency students report participating in those practices. Implications and areas for future research are addressed in the conclusion section.
ADHD assessment and treatment practices among local family practice and pediactric physicians
Blair Burke, Annie Harbison, Valerie Tyndall, and Candace Williams
Faculty Advisor: Cecile Nowatka, Ph.D.
Forty-eight Spartanburg County pediatric and family practice physicians (56%) responded to a questionnaire about diagnostic and treatment practices for ADHD. Contrary to the hypotheses, there was no difference between the two types of physicians. However, physicians who did not use the DSM or a validated scale placed greater emphasis on comorbid problems that are not actually among the DSM criteria for ADHD. Also, these physicians were significantly less likely to use behavioral treatment, which can lower the dosage of stimulant medication that is needed. All of the pediatricians reported using the DSM or a validated scale, and about 60% of the family practice physicians did so. Overall, the respondents reported using stimulant medication twice as much as behavioral treatment. They reported barriers such as time and cost to the family, as well as unavailability of treatment, in referring patients for behavioral therapy.
The roles of discriminative stimuli and motivation level in a three-response sequence
Kara Bennewitz, Tye Tindal, and Wendelyn West
Faculty Advisor: Alliston Reid, Ph.D.
Eight rats were required to press right and left levers to complete an assigned three-response sequence. A tone was presented following the first response, lasting 0.5 s. Tone and No-Tone trials alternated within every session. The tone was hyppothesized to act as a discriminative stimulus and improve accuracy for the responses in the second position. Based on previous research, the accuracy of the third response was also hypothesized to improve. However, the tone did not affect accuracy at either response position. Therefore, a manipulation of motivation was instituted in order to answerthe remaining question, Why would trial accuracy over sessions stablize at 60% rather than 100%? Several sources of errors in responding were identified that potentially caused stabilization at 60%.
The effect of worry on the experience of acute pain
Emily Fort, Leah Gaylord, and Christie Wilkes
Faculty Advisor: John Lefebvre, Ph.D.
Worry is an inevitable part of life, which all individuals experience to varying degrees. However, catastrophizing is a form of worry experienced most by individuals who are higher in anxiety. Characteristically, a catastrophizing worry will begin with “What if…?” and end with a large number of possible (negative outcomes). Catastrophizing leads to hypervigilence and possibly changes in perception regarding the topic of worry. It was hypothesized that there would be a differential effect on pain ratings depending on the topic used in the worry interview. It was also hypothesized that there would be a significant co-relationship between general worry and general pain ratings. This study had 51 undergraduate participants who completed questionnaires pertaining to pain and worry. The participants completed the Forgione- Barber pain assessment before and after a catastrophizing interview. There were two main findings in this study: Asking participants to worry about pain increased their post-interview pain ratings, of the medium and heavy weight stimuli, compared to the other two conditions (squirrel and current worry). Significant correlations were also found between worry and global measures of pain. In summary, the more a person worries in general and the more a person catastrophizes about pain, the more pain they report. Also, the more a person catastrophizes about pain, the more negative affect that person displays, and the greater they report their worst pain being over the past month.
Effect of benzodiazepines on ingestive behavior
Hannah Dinnen and Ivy Farr
Faculty Advisor: David Pittman, Ph.D.
Enhanced palatability has been cited as a basis for benzodiazepine-induced hyperphagia of appetitive stimuli. Using long-term & brief-access tests, we assessed the effect of systemic benzodiazepines on the consumatory responses to sweet, sour, salty, and bitter taste stimuli. Adult male (n=12) & female (n=12) SD rats received either saline or chlordiazepoxide (CDP, 10mg/kg) injections 20 min prior to testing. Long-term tests assessed licking to either 0.075M sucrose, 0.03M citric acid, 0.5M NaCl, or 0.05mM QHCl in daily 90 min sessions. Brief-access tests measured licking to the same stimuli across a range of concentrations during 15 s trials. Significant effects were determined by repeated measures ANOVA (p<0.05). Microanalysis of licking responses revealed significant CDP-induced increases in measures associated with gustatory evaluation (initial licks, burst size, lick rate) with no effects on variables associated with postingestive influences (meal duration, number of bursts). Brief-access tests confirmed significant increases in licking responses to all tastants following CDP injection. CDP increased licking responses to low sucrose concentrations suggesting an increase in the positive hedonic perception. CDP appeared to decrease the aversiveness of strong salty, sour, and bitter stimuli as indicated by increases in licking to high concentrations. There was no effect of CDP on licking responses to water in long-term or brief-access tests or differential effects between males and females. Our findings provide evidence that GABAerigic influences within the gustatory system do not act to enhance the perceived intensity of taste stimuli but rather modulate the hedonic evaluation of appetitive as well as aversive tastants.