Goo-goo over Gaga? Rhapsodic over Rachmaninoff? As most will attest, music has a powerful way of pushing emotional buttons. And now, new research suggests that many of the neural dynamics that control human reaction to song may be shared by another emitter of dulcet tones: birds.
According to a study recently published in Frontiers of Evolutionary Science, when male white-throated sparrows offer up their telltale "birdsong" to their breeding female counterparts, the female experiences the same kind of neurologically driven "reward" that humans do when hearing a favourite tune.
"Scientists since the time of Darwin have wondered whether birdsong and music may serve similar purposes, or have the same evolutionary precursors," Sarah Earp, a former undergraduate at Emory University, explained in a school news release. "But most attempts to compare the two have focused on the qualities of the sound themselves, such as melody and rhythm."
"We found that the same neural reward system is activated in female birds in the breeding state that are listening to male birdsong, and in people listening to music that they like," she said.
How the study was done
Earp's investigation began by reviewing previous research that used brain-imaging technology to map the human neural dynamic that unfolds when listening to music.
Emory lab work had focused on tracking activation of a biochemical marker known as "Egr-1," a key indicator of stimulus response.
Neurological mapping comparisons revealed that, when looking at reward pathways that exist in both humans and birds, the neural response to music observed in humans also kicks into similar gear among breeding female sparrows exposed to a male birdsong.
But timing, as they say, is everything, with non-breeding female birds showing no heightened response to a male's song, while male birds hearing another male "sing" experienced a response akin to that of a person forced to listen to music they hate.
"The neural response to birdsong appears to depend on social context, which can be the case with humans as well," Earp said. "Both birdsong and music elicit responses not only in brain regions associated directly with reward, but also in interconnected regions that are thought to regulate emotion. That suggests that they both may activate evolutionarily ancient mechanisms that are necessary for reproduction and survival."
The caveat: Bird brains are not human brains, and many neural reward pathways are not shared between species. But Earp, now a Stravinsky-loving medial student at Cleveland Clinic, looks forward to digging deeper on the same subject.
"Perhaps techniques will someday be developed," she suggested, "(that) image neural responses in baleen whales, whose songs are both musical and learned, and whose brain anatomy is more easily compared with humans.
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