Alum Studies Brain Basis for Disorders

Posted in GUMC Stories

Depression, anxiety and autism may have more to do with interactions between specific brain structures than dysfunction or disease in one area of the brain, Georgetown researchers say.

Jackie DesJardin (C’11) is leading a project examining this concept in the lab of Ludise Malkova, an associate professor of pharmacology at Georgetown University Medical Center (GUMC).

“What we’ve found is that over-activation of the deep layers of the superior colliculus will cause a number of abnormal social and emotional behaviors and that we are capable of attenuating these abnormal behaviors via inhibition of the amygdala,” says DesJardin, who also works with Patrick Forcelli (G’11).

Poorly Understood Disorders

The superior colliculus is a multilayered structure in the mid-brain. The responses and reactions that result from over-stimulating that structure in animal models may provide clues to depression, anxiety and autism in humans, says the Georgetown alumna.

DesJardin says the research team also found that when the brain’s amygdala is inhibited (increasing social interaction) and the colliculus is over-activated in concert, emotional response is decreased more than when just the colliculus is stimulated.

“The causes of human disorders such as depression, anxiety, autism and other mental illness are poorly understood, and so it is difficult to develop treatments for them,” DesJardin says. “There is no obvious localization of dysfunction in these disorders. And some patients show abnormalities in the amygdala while others do not.”

Subtle Changes

A neurobiology major at Georgetown, the young scientist says the findings suggest that researchers need to look for more subtle changes in the brains of those suffering from such conditions.

“Perhaps the interaction between structures is more important than dysfunction in just one structure,’ says DesJardin, who was a finalist for the Rhodes scholarship last year. “We’re trying to understand how the interaction between these two structures could cause social and emotional disruption.”

Malkova, who holds a 5-year, $1.9 million grant from the National Institute of Mental Health, says the research team uses reversible pharmacological manipulations of different parts of the brain in animal models.

“This approach allows us to better understand the key players within the underlying neural circuitry, how they interact, and the major neurotransmitters involved,” she says. “The main goal is to use this knowledge for future therapy for affective and anxiety disorders.”

Undergraduate Research

DesJardin’s work is a testament a Georgetown program funded by the Howard Hughes Medical Institute.

The program provides a research-intensive, four-year course of study for undergraduates, including mentoring, advanced coursework and extensive science research opportunities.

“The experience opened my eyes to the world of biological research as well as made me a part of an intellectual community comprising faculty and students,” she says.

Uncertain Terrain

DesJardin wants to continue working in Malkova’s lab, publish the team’s work and then pursue a career that allows her to conduct clinical research and practice medicine.

As an undergraduate, DesJardin was voted “defensive MVP” by her Georgetown soccer teammates and this past summer, she played professional soccer in the Pepsi-Deildin Premiere League in Iceland.

“I thrive in that uncertain terrain in which I feel a bit alien and uncertain,” DesJardin says. “It is in that world that I best recognize my potential to both grow and contribute.”

(Published January 6, 2012)