Research by Trinity College Professor of Biology Kent Dunlap and his student Michael Ragazzi ’16 was published in February in one of the world’s oldest scientific journals, Proceedings of the Royal Society B, based in London, England. The paper, which Dunlap and Ragazzi co-authored with researchers from Canada’s McGill University and Cape Breton University, reports that predators inhibit brain cell production in natural populations of electric fish.
The project began with a 2014 trip to Central America by Dunlap and Canadian researchers. Dunlap captured electric fish, Brachyhypopomus occidentalis, to study how stress from predators affects the brains of those fish in their natural habitat.
“I came back from Panama with over 80 fish brains,” said Dunlap. Upon arrival on campus, the frozen fish brains became Ragazzi’s challenge. His focus: how best to assay, or examine for analysis, cell birth in the fish brains — a procedure starting with the use of a cryostat to shave extremely thin brain slices. A biology major, Ragazzi has worked in Dunlap’s research lab since his sophomore year; this is the second research paper they have co-authored.
They found that environmental stressors can have a large impact: fish living among numerous predators produced brain cells at about half the rate as those living among few predators. Although many studies have examined the effect of stress on the brain in laboratory animals, this study is “the first demonstration of predator-induced alteration of brain cell proliferation in a free-living vertebrate,” according to the paper. Their work was funded in part by a Trinity College Faculty Research Committee grant.
Ragazzi said the project was of great value as he considers the possibility of attending medical school. “I appreciate how the experimental questions we explored integrated different scientific disciplines,” said Ragazzi. “Our work required us to read and incorporate aspects of ecology, neuroscience, biochemistry, and psychology.”
A member of the Trinity College faculty since 1998, Dunlap holds a B.A. from Macalester College and a Ph.D. from the University of Washington, Seattle.