After four years of hitting the books, the senior thesis project finally gave Alison Gibbons ’19 the opportunity to touch a brain. The psychology major’s thesis, “Towards a Neurobiology of Peripartum Mood Disorders: DeltaFosB Induction in the Nucleus Accumbens Following a Hormone-Simulated Pregnancy,” was closely interwoven with neuroscience, Gibbons’ minor.
Gibbons’ investigation was developed with her thesis advisor, Assistant Professor Laura Been. Building off the work of previous graduates from Been’s lab, Gibbons and her thesis group sought to discern the effects of ovarian hormones the molecule DeltaFosB and a relationship between this interaction and anxiety behaviors.
“The aim of our project was to understand if reducing the expression of DeltaFosB in the nucleus accumbens would induce anxiety behaviors following a hormone-simulated pregnancy,” she said. “Our model organism was a standard laboratory mouse. The project began by injecting a virus containing a protein that blocked the accumulation of DeltaFosB into the nucleus accumbens of half of our sample, while injecting a control virus into the other half.”
The next step of the process simulated pregnancy in the lab’s subjects. The extended duration of the research gave Gibbons several opportunities to get to know the mice better through an inspection of their brains.
“There is something about looking at a brain during surgery and then examining the tissue following behavior testing that allowed me to understand neuroanatomy better than I had before,” Gibbons said. “We were responsible for locating regions in the brain via microscopic examination of the tissue, an experience that you do not get in your basic neuroscience and psychology classes”
Exposure to these surgical practices allowed Gibbons, who plans to go to medical school and to eventually pursue a career in either neurology or psychiatry, to manifest her prior neurological knowledge in a form not readily available to most undergraduate students in her field.
“This was my first real wet-lab experience, and, as students, we were responsible for every aspect of the research project,” she said. “This research was graduate-level work—when I would tell interviewers what I was doing for thesis, they were shocked by how much students were able to do in the lab.”
What did you learn from working on your thesis?
It taught me the patience that is required to be a real scientist. We had a few major setbacks during our experiment; our mice were not very resilient, leading to a high casualty rate, and one of our main immunofluorescent stains did not work. Both of these lead to a weak statistical power, and extra time in lab brainstorming. With that being said, this is how science is, and it is important to learn how to deal with issues as they come up and be able to roll with the punches.
My biggest takeaway from the project was learning to develop and subsequently answer a research question. In psych and neuro classes at Haverford, we are often asked to describe an experiment to answer a given question, which includes considering a model that would be sufficient to use, controlling for confounding variables that may conflict with results, operationally defining the theoretical variable of interest, determining how we would analyze the data that we received and finally, reporting that data to the public. Some aspect of this idea was touched on in every class that I took in my major, but through thesis I got to put all of these pieces together. I started with a question: what causes anxiety behaviors following pregnancy. This topic is understudied, but hugely important due to the impact of postpartum anxiety on both the mother and the child. After further exploration, it seems that ovarian hormone fluctuations associated with pregnancy contribute to this disorder. Even deeper, a specific brain region, the nucleus accumbens, contains neurons that are implicated in mood and are sensitive to ovarian hormones—these neurons are constantly undergoing plastic change, which is associated with changes in mood and behavior. Therefore, plastic change correlated with hormonal fluctuations in this area could contribute to postpartum anxiety. The way to study this was then to look at factors associated with this plastic change, one of which is DeltaFosB. To look at both of these factors, we had to simulate pregnancy and block DeltaFosB. To control for confounding variables we removed the animals ovaries, their indigenous source of ovarian hormones, which assured all animals were receiving identical hormonal treatments up until our experiment. To operationally define our behavior, anxiety, we used an empirically supported assay, the elevated plus maze. We then analyzed the data, and wrote a full report about our findings and their implications.
“What They Learned” is a blog series exploring the thesis work of recent graduates.