Most Bowdoin students can probably identify what is being served in Thorne by walking past the dining hall without looking at the menu. As the distinct aromas of Honolulu tofu or vegetarian pho noodle bowls waft through the air, the human brain undergoes a complex process in order to recognize and recall that odor.
Senior Rob Parrish is unlocking the subtleties of scent recognition through a series of experiments using rats. Parrish, a neuroscience major, is completing an honors project about how information flows through memory systems.
"More specifically, I am interested in odor recognition and memory in rats," he said.
Parrish uses the rat model in the laboratory to examine these patterns of sensory recognition, since the basic configuration of their hippocampal memory system relates directly to the human's.
Parrish's project began the summer before his senior year, when he worked at Bowdoin as a Howard Hughes Medical Institute Fellow, developing laboratory methods for his upcoming studies. During the fellowship, he learned techniques for training and performing surgery on the rats. He also worked on building electrodes that are used to gather data from individual neurons in rats' brains.
Parrish implants these electrodes into the brains of the rats in order to record the activity of single neurons. By recording the firing rate of these brain cells in rats while they are performing a memory task, he is able to identify patterns in how odors are stored and subsequently recalled.
"I am looking for evidence regarding the direction and time course of information flow between the orbitofrontal cortex, an olfactory processing area in rats, and the hippocampal memory system," he said.
In order to obtain this evidence, Parrish exposes the rats to certain odors and then runs various tests. The shelves of the neuroscience laboratory in Kanbar are stacked with a variety of cooking ingredients: cocoa powder, vanilla extract, and anise, to name a few. These materials are used as odor samples for the rats, Parrish explained.
"We give rats an odor?banana, for example, and then test their ability to recall that same odor after a short delay," he said.
Additionally, the laboratory protocols Parrish has developed over this year will enable Nick Simon '09 to continue the research as an honors project of his own next year.
When asked why he has elected to spend his final months at Bowdoin burrowed away in a windowless lab directing rats around, Parrish did not hesitate in his response.
"There is something inherently interesting about memory," he said. "I am curious in regards to how our brain works, particularly as to how a network of cells translates activity into memories."
Parrish credits his adviser Professor of Psychology and Neuroscience Seth Ramus, and the caliber of Bowdoin's neuroscience program as key enablers for him to conduct this independent research.
"The neuroscience program here is spectacular," said Parrish.
For Parrish, the most rewarding part of the honors project has been the privilege of pursuing independent research and devising the laboratory experiments.
"It is more than a typical classroom experience?much more in-depth and self-driven," he said. "There is something good about working on a project that is your own. It is something you would be hard pressed to find at a larger university."