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."
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