When it comes to the evolution of the brain, bigger doesn’t always mean better, says Dr. Andrew Iwaniuk (MSc ’00).
Iwaniuk is the newly appointed Canada Research Chair in Comparative Neuroanatomy in the Canadian Centre for Behavioural Neuroscience at the University of Lethbridge. Over his five-year term, he will combine evolutionary biology, behavioural ecology and neuroscience to chart the historical course of the brain in order to improve our understanding of brain anatomy and function, both in animals and humans. A key goal is to debunk the notion that larger brains are always more cognitively powerful than smaller ones because they contain more neurons, the cells that process and transmit information.
“This theory doesn’t necessarily hold true, because there are different densities of neurons in the brains of different animals,” says Iwaniuk, who is also an associate professor of neuroscience. “For example, birds pack in more neurons in their brains than primates, even though primates are currently at the top of the list in terms of the number of cells in their brains.”
What we know about bird brains is scarce: data on bird brain anatomy is available for only four per cent of the world’s 10,000 bird species. To that end, Iwaniuk has developed the largest comparative avian brain collection in the world, with more than 600 specimens representing more than 160 bird species. Studying the brains of birds will continue to be one of Iwaniuk’s key research priorities during his CRC term.
Another will be to explore the when and why of large brains, with Iwaniuk seeking to answer questions such as: Why did primates evolve large brains? What are the pros and cons of relatively large brains? And, what mechanisms underlie the evolution of relatively large brains? He will look for the answers in existing data on human fossil history, and on the evolutionary trajectories of animals such as birds, fish, reptiles and amphibians.
Examination of bird brains will not be limited to the species around today, as Iwaniuk will also examine brains of extinct species through digitally reconstructing their brains from skulls. This is important, he says, because the anatomy of the brain can be used to determine the sensory and cognitive abilities of extinct species. He is currently collaborating with a researcher at National Museums Scotland to study the brain of the dodo, a species symbolic of extinctions caused by humans, to determine its sensory abilities, how it fit into the ecology of its home on the island of Mauritius, and why the species became extinct.
Finally, Iwaniuk will develop a publicly accessible electronic archive of his collection of avian brain data in order better facilitate existing and future national and international research collaborations. Ultimately, he would like to establish his lab as a top Canadian centre for evolutionary neurobiology.
In the classroom, Iwaniuk will create a new course that focuses on the natural behaviour of animals in the environment and how that behaviour is modulated by species differences in the brain. He will also create opportunities for undergraduate and graduate students from around the world to gain hands-on learning experiences by assisting with his research.
As his research progresses, Iwaniuk hopes the insights that emerge about brain evolution will tell us more about what makes the human brain unique, which could ultimately affect the way we treat human diseases.
“Better understanding the fundamental differences in how different brains are organized relative to one another can teach us about more effective ways to treat neurological conditions and disorders,” he says.