Kristin Olesen studies hormone's effects on birds' brains
Kristin Olesen, a Johns Hopkins University senior from Racine, Wis., is researching the biochemical changes that occur in birds' brains when sexual rivals enter their turf, triggering defensive outbursts of song.
Olesen's original research, focusing on an early link in a long chain-reaction that connects increased hormone production in male birds to their increased singing, has been funded with support from a Johns Hopkins Provost's Undergraduate Research Award (PURA). As one of 41 PURA winners this academic year, she will present the results of her research at an awards ceremony held at Johns Hopkins on April 1.
Since 1993, about 40 students each year have received PURA grants of up to $2,500 to conduct original research, some results of which have been published in professional journals. The awards, funded through donations from the Hodson Trust, are an important part of the university's commitment to undergraduate student research.
Working under sponsor Greg Ball, a professor of psychological and brain sciences at Johns Hopkins, Olesen has been administering doses of the hormone estradiol to canaries. Estradiol is found in estrogen and is a byproduct of testosterone.
Ball's overall research program works to link changes in songbird behavior to molecular-level mechanisms and reactions in bird brains. Study of the simpler brains of model organisms allows researchers to directly test and observe biochemical processes and can yield useful insights for scientists working to understand the more complex human brain.
"There's some evidence from field studies that when male birds are in a territorial frame of mind during mating season and an invader comes into their territory, they will experience a rapid surge in testosterone production, which is closely followed by increased singing," Olesen explains. "Basically, song is their way of defending their turf, and what we're looking for is how is that rapid surge of testosterone relates to the behavior."
After exposing the birds to estradiol, Olesen examines regions of the birds' brains involved in song production and sexual activity for the presence of cyclic AMP response element binding protein (CREB). When modified through a biological process known as phosphorylation, a phenomenon that occurs more often in the presence of competitors, CREB can act as a transcription factor, promoting the creation of other proteins by binding to DNA. Scientists suspect these other proteins may help trigger brain changes that permit a bird to challenge invaders with a burst of song.
"What I'm looking at right now is just one of multiple, multiple transcription factors that could potentially be activated," Olesen explains. "Once I get done with this protein, I'm hoping to look at tyrosine hydroxylase."
Preliminary evidence from one of the Ball research group's collaborators has shown that tyrosine hydroxylase also gets phosphorylated at an increased rate after a hormone surge.
Olesen will graduate from Johns Hopkins this spring, and plans to attend graduate school, where she hopes to continue to study similar brain mechanisms in rats. Olesen, who graduated from St. Catherine's High School in 1999, is the daughter of Jeffrey and Lynn Olesen.
The 10th annual PURA ceremony, where Olesen presents her research results on April 1, will be hosted by Steven Knapp, university provost and senior vice president for academic affairs. The entire Johns Hopkins community is invited to the event.
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