Bryn Mawr Senior Beverly Burgess
Wins Research-Poster Competition
Beverly Burgess '07, a double major in biology and psychology, recently won first prize for most outstanding undergraduate poster at the Drexel University College of Medicine's Discovery Day, an annual event at which the results of biomedical research are presented.
The competition was open to Drexel medical students, postdoctoral fellows, technicians and residents, as well as undergraduate and a high-school student researchers from schools across the country. Participants were judged on subject matter, professionalism and presentation, including their ability to field questions as well as the organization and effectiveness of the poster itself. About 205 posters were presented at this year's competition.
Burgess presented research she undertook as a summer undergraduate research fellow at the medical college. During the 10-week program, she participated in a preliminary study designed to contribute to the understanding of sex differences in attention. The diagnosis of attention deficit hyperactivity disorder is made much more frequently for boys than for girls, Burgess explains, and the study used an animal model of attention to determine whether gender differences in attention exist and whether a drug commonly prescribed for ADHD affected male and female rats differently. The principal investigator for the study was Drexel College of Medicine Professor Barry Waterhouse; Burgess worked on the project with Research Assistant Professor Jed Shumsky.
Burgess worked with a population of 12 water-restricted rats, six male and six female, who learned to associate pressing a lever with receiving a water reward. Each rat was placed in a chamber which had two levers and a stimulus light on one wall; water was dispensed on the opposite wall. Once the rats had learned to associate the water reward with depressing either level, Burgess says, We switched the rules on them.
If the stimulus light was randomly lit during a 15-second interval, pressing one lever resulted in the water reward. If it wasn't lit, the other lever yielded the water. During the first phase of the experiment, the light was illuminated for a full second. For a second, more difficult trial, it was lit for only 15 milliseconds. This duration, Burgess explains, is just above the threshold of detection so rats who were not paying attention would likely miss the cue. The rats' acquisition rate and performance on these tasks was captured and a score was generated for each animal.
In the first phase of the experiment, the female rats learned the task more quickly and performed it better, Burgess reports. In the second phase, which was shortened by an outbreak of virus among the test animals, no clear sex differences emerged. When administered methylphenidate, commercially known as Ritalin, the rats' performance uniformly improved, with no pattern of difference between male and female rats. Overall, Burgess says, the results confirm that gender differences in attention exist and suggest that these differences lie outside of the monoaminergic system, on which methylphenidate acts.
It was a preliminary study, and we had hoped to spend more time on the second phase, Burgess says. The experiment will probably be repeated with a larger population of test animals.
Burgess found the project both challenging and rewarding. I had a great time working with a very collaborative group of graduate students and PhDs on this project," Burgess says. It feels great to know that I have done a good job of representing Bryn Mawr at this event.
A McBride Scholar who plans a career in medicine, Burgess performed with a ballet company and worked for a management-consulting firm before coming to Bryn Mawr. She applied to the competitive summer internship program at Drexel to get a taste of biomedical research to help her to decide whether she would like to incorporate research into her medical career. This year, she will be working under the supervision of Associate Professor of Psychology Anjali Thapar on senior-thesis research dealing with the effects of aging on memory.
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