Once Deaf, Bird Brains Can’t Keep a Tune: Deaf Equals DisharmonyBy: Shawn Hess - March 21, 2012
Duke University Medical Center has released a new finding that pertains to songbirds and may have implications for other creatures including humans. It’s a known fact that neural pathways that are constantly activated will strengthen over time, but the inverse might be true as well.
Researchers monitored songbirds who lost their ability to hear and observed changes in their braincells in as little as 24 hours. The rapid response of the braincells came as a surprise to researchers on the study.
Senior author of the study, Richard Mooney, PhD, professor of neurobiology at Duke, commented on the findings:
“When hearing was lost, we saw rapid changes in motor areas in that control song, the bird’s equivalent of speech,”
“This study provided a laser-like focus on what happens in the living songbird brain, narrowed down to the particular cell type involved.”
Here’s a look at the neurons in question when analyzed under a microscope after being injected with flourescent matter from a jellyfish:
“I will go out on a limb and say that I think similar changes also occur in human brains after hearing loss, specifically in Broca’s area, a part of the human brain that plays an important role in generating speech and that also receives inputs from the auditory system,”
“Our vocal system depends on the auditory system to create intelligible speech. When people suffer profound hearing loss, their speech often becomes hoarse, garbled, and harder to understand, so not only do they have trouble hearing, they often can’t speak fluently any more,”
“I was very surprised that the weakening of connections between nerve cells was visible and emerged so rapidly — over the course of days these changes allowed us to predict which birds’ songs would fall apart most dramatically,”
I guess these aren’t surprising results, but sad for the birds involved in the study. Of course losing your hearing is going to effect your ability to carry a tune. What implications this holds for humans, other than providing evidence that we share similar characteristics with birds, I do not know.