Who’s a pretty and clever boy, then? Neuroscientists at the University of Alberta have identified the neural circuit they believe is behind the unusual intelligence seen in some parrots. The discovery is an example of convergent evolution – where organisms not closely related evolve similar traits – between the brains of birds and primates, and could potentially provide insight into the neural basis of human intelligence, they say.
Using brain samples from 98 birds, including everything from chickens and waterfowl to parrots and owls, the scientists studied an area of the brain known as the medial spiriform nucleus (SpM). They found that parrots have an SpM that is much larger than that of other birds, possibly explaining their unusual levels of intelligence.
In birds, the SpM is responsible for transferring information between the two largest areas of the brain, the cortex and cerebellum, which allows for higher-order processing and more sophisticated behaviour. In humans and other primates, the pontine nuclei performs this same function.
“The SpM is very large in parrots. It’s actually two to five times larger in parrots than in other birds, like chickens,” said Dr Cristian Gutierrez-Ibanez, who co-authored the research. “Independently, parrots have evolved an enlarged area that connects the cortex and the cerebellum, similar to primates. This is another fascinating example of convergence between parrots and primates. It starts with sophisticated behaviours, like tool use and self-awareness, and can also be seen in the brain. The more we look at the brains, the more similarities we see.”
Next, the research team hopes to study the SpM in parrots more closely, to understand what types of information go there and why.
“This could present an excellent way to study how the similar, pontine-based process occurs in humans,” said Gutierrez-Ibanez. “It might give us a way to better understand how our human brains work.”