Summary: A new study of parrots reveals evidence of convergent evolution between bird and primate brains. The findings have the potential to shed light on the neural basis for human intelligence.
Source: University of Alberta.
University of Alberta neuroscientists have identified the neural circuit that may underlay 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 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 behaviour. 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 behaviours,” said 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 Gutierrez. “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,” added Gutierrez. “It might give us a way to better understand how our human brains work.”
About this neuroscience research article
Source: Katie Willis – University of Alberta Publisher: Organized by NeuroscienceNews.com. Image Source: NeuroscienceNews.com image is in the public domain. Original Research: Open access research for “Parrots have evolved a primate-like telencephalic-midbrain-cerebellar circuit” by Cristián Gutiérrez-Ibáñez, Andrew N. Iwaniuk & Douglas R. Wylie in Scientific Reports. Published July 2 2018. doi:10.1038/s41598-018-28301-4
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[cbtabs][cbtab title=”MLA”]University of Alberta”Researchers Uncover Secret to Intelligence in Parrots.” NeuroscienceNews. NeuroscienceNews, 3 July 2018. <https://neurosciencenews.com/intelligence-parrots-9511/>.[/cbtab][cbtab title=”APA”]University of Alberta(2018, July 3). Researchers Uncover Secret to Intelligence in Parrots. NeuroscienceNews. Retrieved July 3, 2018 from https://neurosciencenews.com/intelligence-parrots-9511/[/cbtab][cbtab title=”Chicago”]University of Alberta”Researchers Uncover Secret to Intelligence in Parrots.” https://neurosciencenews.com/intelligence-parrots-9511/ (accessed July 3, 2018).[/cbtab][/cbtabs]
Parrots have evolved a primate-like telencephalic-midbrain-cerebellar circuit
It is widely accepted that parrots show remarkable cognitive abilities. In mammals, the evolution of complex cognitive abilities is associated with increases in the size of the telencephalon and cerebellum as well as the pontine nuclei, which connect these two regions. Parrots have relatively large telencephalons that rival those of primates, but whether there are also evolutionary changes in their telencephalon-cerebellar relay nuclei is unknown. Like mammals, birds have two brainstem pontine nuclei that project to the cerebellum and receive projections from the telencephalon. Unlike mammals, birds also have a pretectal nucleus that connects the telencephalon with the cerebellum: the medial spiriform nucleus (SpM). We found that SpM, but not the pontine nuclei, is greatly enlarged in parrots and its relative size significantly correlated with the relative size of the telencephalon across all birds. This suggests that the telencephalon-SpM-cerebellar pathway of birds may play an analogous role to cortico-ponto-cerebellar pathways of mammals in controlling fine motor skills and complex cognitive processes. We conclude that SpM is key to understanding the role of telencephalon-cerebellar pathways in the evolution of complex cognitive abilities in birds.