May 7, 2018 by Elizabeth Braun, University of Chicago
Asst. Prof. Sarah London has long appreciated zebra finches for their unique learning characteristics. The males learn from another male tutor, but their ability to memorize the tutor's song is restricted to a "critical period," or CP. This offers a unique opportunity to study how the brain learns, and how brain processes affect whether or not a mentor's song can be learned, London said.
Previous research has shown that males who had experienced a tutor in their first 65 days of post-hatch life could no longer learn a song after that, but that young males isolated from hearing song during this period were still able to learn a song after day 65. What researchers hadn't deciphered until now was what preserved or prevented these late learning capabilities.
In a new study, London's team found the first comprehensive explanation for this in an epigenetic mechanism, a process in the brain by which experience—in this case, tutor experience—can modify structural properties of the genomic DNA. London and her team demonstrate measurable and repeatable epigenetic differences between the brains of zebra finches who receive tutoring, and those that do not.
These epigenetic differences directly relate to levels and patterns of gene expression in the brains of finches that can still learn from a tutor compared to those that can no longer learn song.
London believes the results of this study could have future implications for helping trauma patients to prevent encoding those events into their long-term memory, as well as advancing our understanding of how young children learn, and what can be done to enhance learning capabilities among disadvantaged youth in order to level the playing field of learning among children entering school.
"These results help us understand complex genomes in the context of the everyday learning experience," London said. "It decouples the actual experience from the genomic process happening in the brain, and this knowledge could be a guide to therapeutics."