Summary: Success at learning a second language may be a result of your genetics and brain structure, a new study reports.
Source: University of Washington.
If you’ve had disappointing results in learning a new language as an adult, your struggle may have to do with your genes and brain structure.
A new study by researchers at the University of Washington shows that the final grades that college students received in a second-language class were predicted by a combination of genetic and brain factors.
Genetic variations of the COMT gene and a measure of the strength of the brain’s communications network — known as “white matter”– jointly accounted for 46 percent of the reason for why some students performed better than others in the language class.
“We are interested in understanding why individuals learn differently, including those who perform well and those who perform poorly,” said lead author Ping Mamiya, a research scientist at the UW’s Institute for Learning & Brain Sciences (I-LABS).
“Our study shows for the first time that variations of the COMT gene are related to changes in the brain’s white matter that are the result of learning,” Mamiya said.
The Proceedings of the National Academy of Sciences will publish the study this week.
“We all know that human learning is highly complex and that a lot of factors play a role,” said co-author Patricia Kuhl, co-director of I-LABS. “Second-language learning as an adult is difficult, and we thought studying how people learn something difficult would be a good way to tease out the interactions between genes and brains in learning.”
The research team recruited first-year college students — 20-years-old on average — who had just arrived in the U.S. from China. The 79 volunteers in the study had passed the university’s minimum English requirement, and 44 of them immediately entered a three-week immersion class intended to help international students improve their English skills.
Over the course of the three-week language class and up to eight days after the class ended, the researchers performed brain scans of all the students, including a control group who had also just arrived from China but did not get into the class.
The researchers used an MRI technique called diffusion tensor imaging (DTI), which gives clues about the structure of the brain’s connections. Better structure helps signals transfer across the brain, which may lead to better learning.
The brain scans suggest that within a day of the immersive English training, white matter had already begun to change. Foreign language exposure increased the connectivity of the brain’s language circuitry in enrolled students compared with students who were not enrolled in the language class. The increase went up over the course of the three-week training, and then reversed after the training ended.
“Being able to document these associations between brain structure and environmental stimulation in young adult human brains is really exciting,” Mamiya said. “It is one of the highlights in this paper.”
Since different forms of the COMT gene can have different effects on brain structure, the researchers suspected that the students’ COMT genotype would be related to how much white matter changed from the language class.
Sure enough, using DNA samples taken from the students at the beginning of the language program, the researchers found that two specific forms of the COMT gene (Methionine/Valine or Valine/Valine) were linked to greater increases in brain connectivity in students who took the language class. Students with a third COMT genotype (Methionine/Methionine) did not show any white matter change in response to the language experience.
The combination of the COMT genotype and the white matter measure was so powerful on language learning that it accounted for 46 percent of total variance in the students’ final scores.
“Humans’ abilities in learning any particular skill vary tremendously, and we want to know why,” Kuhl said. “Knowing why answers a basic science question about how the environment, our genes, and our brains really work, but could also lead to interventions that improve learning.”
About this genetics research article
Funding: Other co-authors of the study are Todd Richards of the UW Department of Radiology, and Bradley Coe and Evan Eichler of the UW Department of Genome Sciences. The National Science Foundation’s UW Life Center and the Ready Mind Project at I-LABS funded the study.
Source: Abigail Pattenden – University of Washington Image Source: This NeuroscienceNews.com image is in the public domain. Original Research: Full open access research for “Brain white matter structure and COMT gene are linked to second-language learning in adults” by Ping C. Mamiya, Todd L. Richards, Bradley P. Coe, Evan E. Eichler, and Patricia K. Kuhl in PNAS. Published online June 13 2016 doi:10.1073/pnas.1606602113
Cite This NeuroscienceNews.com Article
[cbtabs][cbtab title=”MLA”]University of Washington. “Success in Second Language Learning Linked to Genetic and Brain Measures.” NeuroscienceNews. NeuroscienceNews, 13 June 2016. <https://neurosciencenews.com/genetics-second-language-white-matter-4457/>.[/cbtab][cbtab title=”APA”]University of Washington. (2016, June 13). Success in Second Language Learning Linked to Genetic and Brain Measures. NeuroscienceNews. Retrieved June 13, 2016 from https://neurosciencenews.com/genetics-second-language-white-matter-4457/[/cbtab][cbtab title=”Chicago”]University of Washington. “Success in Second Language Learning Linked to Genetic and Brain Measures.” https://neurosciencenews.com/genetics-second-language-white-matter-4457/ (accessed June 13, 2016).[/cbtab][/cbtabs]
Brain white matter structure and COMT gene are linked to second-language learning in adults
Adult human brains retain the capacity to undergo tissue reorganization during second-language learning. Brain-imaging studies show a relationship between neuroanatomical properties and learning for adults exposed to a second language. However, the role of genetic factors in this relationship has not been investigated. The goal of the current study was twofold: (i) to characterize the relationship between brain white matter fiber-tract properties and second-language immersion using diffusion tensor imaging, and (ii) to determine whether polymorphisms in the catechol-O-methyltransferase (COMT) gene affect the relationship. We recruited incoming Chinese students enrolled in the University of Washington and scanned their brains one time. We measured the diffusion properties of the white matter fiber tracts and correlated them with the number of days each student had been in the immersion program at the time of the brain scan. We found that higher numbers of days in the English immersion program correlated with higher fractional anisotropy and lower radial diffusivity in the right superior longitudinal fasciculus. We show that fractional anisotropy declined once the subjects finished the immersion program. The relationship between brain white matter fiber-tract properties and immersion varied in subjects with different COMT genotypes. Subjects with the Methionine (Met)/Valine (Val) and Val/Val genotypes showed higher fractional anisotropy and lower radial diffusivity during immersion, which reversed immediately after immersion ended, whereas those with the Met/Met genotype did not show these relationships. Statistical modeling revealed that subjects’ grades in the language immersion program were best predicted by fractional anisotropy and COMT genotype.
“Brain white matter structure and COMT gene are linked to second-language learning in adults” by Ping C. Mamiya, Todd L. Richards, Bradley P. Coe, Evan E. Eichler, and Patricia K. Kuhl in PNAS. Published online June 13 2016 doi:10.1073/pnas.1606602113