New study uses mice to unlock the secrets of language learning

First published in Around the O on October 16, 2020.

A pair of UO researchers have questions about how humans learn second languages, and they believe they will find some answers in the brains of mice.

Linguistics professor Melissa Baese-Berk and neurobiologist Santiago Jaramillo are teaming up on a new research project that will combine their two areas of expertise to probe how humans learn languages and to better understand the neural mechanisms underlying that learning. They were awarded a $1 million grant from the National Science Foundation to pursue the work.

“This project will investigate how we can improve the efficiency of learning a second language,” Jaramillo explained. “If we can better understand the learning mechanisms in the brain, we can translate that to better learning strategies.”

The idea for the project stemmed from an experiment that Baese-Berk conducted during graduate school at Northwestern University, where she examined how humans learn to differentiate similar sounds in language learning, like a trilled “r” in “perro," the Spanish word for dog, and the tapped “r” in “pero,” which is translated as the conjunction “but.”

Through that experiment, Baese-Berk looked at the interplay between passive learning, which can happen through an activity like playing Spanish music in the background, and actual practice, where learners are actively trying to train their brain to acquire and retain the information.

“We found that when learners incorporated both passive learning and practice, they could learn the new language in a way that rivaled pure practice and study,” said Baese-Berk, a David M. and Nancy L. Petrone Faculty Scholar who specializes in speech perception and production, especially in nonnative listeners and speakers. “But I wanted to know more about why humans are able to learn that way.”

Baese-Berk’s study provided important insights into how humans learn through listening, but it left her wondering why this was the case. She had uncovered a behavioral pattern and wanted to better understand what was happening in the brain to enable that reality. 

Enter mice brains and Jaramillo, who specializes in the neural basis of auditory cognitive processes, essentially exactly what Baese-Berk was hoping to understand: how the brain is learning sounds.

The collaboration between the two researchers started with casual conversations about their mutual research interests, and after they realized how much some of their work overlapped, they got excited about combining forces on a research project. So they applied for seed funding through the Incubating Interdisciplinary Initiatives award program, an initiative designed and funded by the UO’s Office for Research and Innovation.

The initial funding allowed them to start working together and assembling preliminary findings that demonstrate the project’s viability to the National Science Foundation. They both credit the UO’s early support for helping them launch the project and get critical outside funding to continue pursuing research.

Now they are off the ground and running with a collaborative, two-pronged approach to their research question. They will work together on the project, with Baese-Berk leading an experiment looking into human behavior with language learning and Jaramillo spearheading the research behind what happens in the brain while that learning is taking place.

To investigate this question, Jaramillo is using mice because their mammalian brains resemble those of humans, and he can examine them with a level of sensitivity and precision that is unattainable with human brains.

Jaramillo starts by training the mice to respond to different complex language sounds using a reward system, much like someone would train a puppy. He then tracks what’s happening in the brain when they hear those similar-sounding syllables from human language.

The highly advanced tools and techniques in Jaramillo’s lab allow him to collect incredibly precise data about the neural activity of the mice during their learning exercises. He captures hundreds of different cells on video and uses computational methods to help analyze the high volume of footage from the brain cameras.

“We can see how the brain is learning by analyzing how the brain cells respond to different sounds,” Jaramillo explained.

They essentially look for changes in the clouds of responses produced by the cells, which offers insights into what is happening in the brain during different types of listening and learning.

Jaramillo’s analysis of the neural activity helps him extract a meaningful hypothesis about what is transpiring in the brain during learning, which he can then turn over to Baese-Berk to test on human learners.

They hope their complimentary research acts as a cyclical generator of new insights and new research questions that will help them gain better understanding into how humans can learn most efficiently.

“Second language learning is critically important in our increasingly global society,” Baese-Berk said. “An improved understanding of how language learning works, from neurons to behavior, will help us develop more efficient learning strategies.”

By Emily Halnon, University Communications