Adding a new twist to the insult "bird brain," researchers at the University of Chicago Medical Center made an interesting discovery. It turns out some brain cells in birds form the same kind of circuitry that are linked to intelligence in humans. Actually, they found the same thing in reptiles too. Cell circuitry and molecular signatures linked to cognitive abilities in humans are believed to exist in birds too.
Cell types in birds' brains "linked to goal-directed behaviors and cognition are similar to cells in the mammalian neocortex," according to Science Daily. The discovery suggests that even though the structures of bird and reptile brains are different from humans, they still function using the same shared set of neuron types.
In mammals, the neocortex is where most higher-order cognitive processing takes place.
"Birds are more intelligent than you think, and they do clever things," Dr. Clifton Ragsdale, professor of neurobiology at the University of Chicago and senior author of the paper said. "What this research shows is that they're using the same cell types with the same kinds of connections we see in the neocortex, but with a very different kind of organization."
Mammals have a neocortex. Birds have a structure called a dorsal ventricular ridge (DVR). Both develop from an embryonic region called the telencephalon. Yet, these two brain structures mature into totally different shapes. Plus, while the neocortex in mammals is made up of six layers, the dorsal ventricular ridge in birds has large clusters of neurons.
Scientists long speculated that this area of bird brains didn't correspond to the mammalian neocortex. Rather they likened it to the amygdala.
This new study shows that populations of neurons in bird brains share a molecular signature with IT neurons. The IT neurons make an important link in the circuitry of the neocortex.
"The structure of the avian DVR looks nothing like the mammalian neocortex, and this has historically been a huge problem in comparative neuroscience," graduate student Steven Briscoe, who led the research team, said. "Anatomists have debated how to compare the DVR and neocortex for over a century, and our identification of IT neurons in the bird DVR helps to explain how such different brain structures can give rise to similar behaviors."
These findings suggest that birds and primates started with the same shared cell types that went on to evolve intelligence independently, according to the article published in Current Biology.
Some people don't realize that birds have large brains compared to their bodies. Many don't realize that neurons in the bird brain are packed more densely that neurons in the primate brain. Now, we may be learning that they might be more like us than we previously thought.