In University of Lynchburg’s Physiological Psychology Lab, the zebrafish are exercising. No, the striped, guppy-like fish aren’t doing step aerobics in tiny sneakers, but what they are doing is helping a team of researchers learn about the effects of exercise on anxiety.
The idea, conceived by psychology professor Dr. Keith Corodimas, was to take zebrafish living in “impoverished” conditions — without plants, rocks, or other fish for company — and see if their behavior changed after being exposed to exercise.
These fish would be compared to fish living in impoverished environments that weren’t exercised and fish living in “enriched” environments — with plants, rocks, and company — that were exercised and not exercised. The initial hypothesis was that exercise would make all of the fish, regardless of environment, less anxious.
Because it’s a pilot project and a “huge area” according to Dr. Corodimas, it’s too soon to tell what the research will reveal. “We’ll never be able to put a dent in it, but we’re certainly going to try in my 10-plus years till I retire,” he said, adding, “I wish I was starting my career now. There’s so much to do here, for so many students.”
While using zebrafish as model organisms for humans is nothing new, Dr. Corodimas said the research he and his students are doing is the first of its kind. Researchers in Brazil have studied whether learning is enhanced in zebrafish who were exercised, and others have studied how exercise affects metabolism and muscle growth. This is something altogether different.
“We are looking at whether exercise can reduce or prevent the detrimental effects of fish living in socially- and structurally-impoverished environments,” Dr. Corodimas said. “This is extremely novel. Virtually all exercise research in non-mammalian vertebrates, like fish and baby alligators, has looked at effects on metabolism, muscle growth, etc., but not behavior.
“Living in social isolation or in a physically-impoverished environment has terrible maladaptive effects on the brain and behavior. The question is: Can daily physical activity reduce, prevent, or even reverse these well-known maladaptive effects on the brain and behavior?”
‘Research Dream Team’
To help him answer these and other questions, Dr. Corodimas assembled what he calls his “Research Dream Team,” or RDT for short: Meagan Collins ’18, Katie Roderick ’19, and Mihika Corodimas ’19. “They’re some of our best students,” he said. “I feel so lucky.”
For Collins, who introduced the project at the Student Scholar Showcase in April, it’s not the first time she’s worked with zebrafish. She has studied the effects of L-DOPA, a drug used to treat Parkinson’s and other diseases, on zebrafish and anxiety.
After she graduates in May with degrees in psychology and biomedical science, Collins will head to Montreal’s McGill University, where she’ll pursue a PhD in neuroscience. There, she’ll work under Dr. Myriam Srour, a scientist who uses zebrafish and other model organisms to study congenital mirror movement disorder.
Roderick, a psychology major who plans to pursue a PhD in neuroscience, said working with the RDT and Dr. Corodimas has been an “absolute delight” and that it’s “so rare for undergraduate students to be able to conduct novel research.”
The experience also will help Roderick meet her career goals. “I plan on becoming a professor and I would love to do research with undergraduate students, so this whole experience has given me ideas on how I want to go about that in the future,” she said.
Mihika Corodimas — yes, she’s Dr. Corodimas’ daughter — said that in addition to learning more about the trial and error involved in scientific research, she’s learned a lot about herself. “I’m typically introverted,” she said. “But when I’m taking part in something I’m highly passionate about and doing so with others I enjoy being around, I step out of my comfort zone [and] become more social, take initiative, take on leadership, etc.”
Asked about working with his daughter, Dr. Corodimas said, “It’s been fun. Actually, it’s been a real highlight of my life. She’s in my class, too. It’s just amazing. I really feel so lucky. When your kid goes to college, usually you hardly see them. I see her every day.”
One doesn’t just start exercising zebrafish overnight. In addition to assembling a research team, it takes planning, along with a means by which to make the fish exercise. What the team needed was an endless pool of sorts — actually, two endless pools — made just for fish.
Because these kinds of setups are expensive, as much as $10,000 each, some do-it-yourself-ing was in order to accommodate a significantly smaller budget. “That was stressful because I don’t know squat about any of that,” Dr. Cordimas admitted.
Undeterred, Dr. Corodimas searched the internet, he talked with plumbers, and he found a glass blower in Texas who could make tubes for the fish to swim in. He bought pumps, flowmeters, and PVC tubing. There were screens for both ends of the glass tubes “to prevent the fish from swimming into the pump or out the downstream end,” water heaters to keep the fish warm, and a couple of food-grade agricultural troughs to hold everything. And, of course, water.
And when they finally flipped the switch? “It worked like a charm,” he said. “I had tears in my eyes.”
So, this was the plan: Every day, for two weeks, groups of zebrafish — 60 total — would swim against a current for 10 minutes. In addition to using state-of-the-art software to track, record and analyze the fishes’ movements, the researchers would use two tests to see if the exercise caused the fish to become less anxious: the light/dark test and novel tank test.
For the first test, the fish were placed in a box that was painted half white and half black. Dr. Corodimas said anxious fish prefer the dark half. For the novel tank test, fish were placed in an unfamiliar tank. “Anxious fish swim toward the bottom,” he said. “They don’t swim toward the top until they’re comfortable. There are thousands of studies about that. These are very simple but very reliable tests.”
Because it’s a pilot project and the first of its kind to boot, Dr. Corodimas said there is some tweaking to do, regarding things like how long to exercise the fish and at what intensity. “We’re working on the paradigm,” he said. “How much exercise? How intense should it be? What works in your lab, with the equipment that you have? You have to look at what works for you in your lab with students.”
This summer, after Collins graduates, Roderick and Mihika Corodimas will continue their zebrafish research on campus with a $3,100 grant from Lynchburg’s Faculty Development Committee. The project also has received funding from the Schewel and Wootton funds.
“We’ll be shifting gears to focusing on social isolation in zebrafish,” Roderick said. “We plan on getting a lot of the pilot work done. My thesis next year will be focusing on social isolation, so I’m hoping that the work we do this summer will be a good jumping off point for when I return in August.”
Her research partner, a psychology major who plans to earn a master’s degree in mental health counseling and a PhD in clinical psychology, added that “significance is sometimes not found during pilot research, but this first step is essential in that it provides the researchers with the knowledge of what to replicate, what to avoid, and what to improve on in future research. Ultimately, it’s a time for … establishing a more effective procedure or experiment that has an increased chance of yielding significant findings.”
Dr. Corodimas hopes he and his students will discover a lot about zebrafish over the summer and throughout the next academic year. “It’s been unforgettable,” he said of the experience thus far. “It’s been great. They’ll be presenting [their research] and if things go well, publishing. … I’d love for these two to get published.”