Large Spiriform Nucleus (SpM) May Be Secret to Intelligence in Parrots; Key Brain Structure Is Much Larger in Parrots Than in Other Birds

University of Alberta neuroscientists have identified the neural circuit that may underlie intelligence in birds, according to a new study. The discovery is an example of convergent evolution between the brains of birds and primates, with the potential to provide insight into the neural basis of human intelligence. "An area of the brain that plays a major role in primate intelligence is called the pontine nuclei," explained Dr. Cristian Gutierrez-Ibanez, postdoctoral fellow in the Department of Psychology. "This structure transfers information between the two largest areas of the brain, the cortex and cerebellum, which allows for higher-order processing and more sophisticated behavior. In humans and primates, the pontine nuclei are large compared to other mammals. This makes sense given our cognitive abilities." Birds have very small pontine nuclei. Instead, they have a similar structure called the medial spiriform nucleus (SpM) that has similar connectivity. Located in a different part of the brain, the SpM does the same thing as the pontine nuclei, circulating information between the cortex and the cerebellum. "This loop between the cortex and the cerebellum is important for the planning and execution of sophisticated behaviors," said Dr. Doug Wylie, Professor of Psychology and co-author on the new study. Using samples from 98 birds from the largest collection of bird brains in the world, including everything from chickens and waterfowl to parrots and owls, the scientists studied the brains of birds, comparing the relative size of the SpM to the rest of the brain. They determined that parrots have a SpM that is much larger than that of other birds. "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. Gutierrez.
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