Songbirds and people share the rare ability to learn vocal patterns through imitation, a skill driven by similar brain areas that have functionally converged over evolutionary time. This is true even at the genetic level. Songbird gene expression in these brain regions more closely resembled that of humans’ than that of chickens’, and human gene expression was closer to that of songbirds than to that of a fellow primate, the macaque.
Current finch models of Parkinson’s rely on neurotoxin-induced lesions in specific brain areas, not genetic mutations associated with the disease in people. However, Parkinson’s affects the entire brain—not just the basal ganglia—as well as peripheral nerves, muscles, and gut, says neuroscientist Michelle Ciucci of the Department of Communication Sciences & Disorders. Her work on speech and swallowing defects in Parkinson’s patients and in rodent models of the disease has shown that dopamine replacement doesn’t noticeably improve speech quality in Parkinson’s patients, suggesting that a dearth of the neurotransmitter is not the sole cause of these deficits. Because genetic models can better recapitulate the progression and wider effects of Parkinson’s, Ciucci advocates using a combination of these models—including both rodents and finches—to understand the biology of the disease.