Bird Brains Use Unique Structure to Support High Intelligence

Biological Strategy

Leo Zsembik

Image: Pete Beard / Creative Commons / CC BY - Creative Commons Attribution alone

Learn

Living systems obtain information from their environment and use it to find mates and resources, and to escape threats. Some reactions to gathered information are instinctual or innate behaviors, not based on previous experiences. But other reactions are based on previous experiences, which means that, at some level, the living system is learning. Learning can involve a living system passing information to another living system, or a living system obtaining information and using it in a feedback loop. That information can include knowledge, experience, behavior, and skills. Learning takes place when information that is new to the recipient is used to modify existing behavior or skills. The making and use of tools by some species of birds and mammals is a learned behavior. If a chimpanzee uses a stick to successfully get ants out of an ant mound and continues to do so, it has learned that behavior. If another chimpanzee observes this technique and replicates it, it has learned from the first chimp.

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Compute

Computation allows an organism to take in and process information to make decisions. Whether it be calculating how fast prey is moving or deciding where to build a nest, computation is an important part of an organism’s life.

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Animals

Kingdom Animalia (“having breath or soul”): Mammals, reptiles, sponges, corals, insects, birds

This kingdom captures a staggering variety of life—from the smallest coral polyp to the largest elephant. Although animal body shapes and life histories vary, there are a few defining characteristics. Animals are heterotrophs, meaning they gain energy from eating other organisms, and have developed from single-celled ancestors to highly diversified and coordinated multicellular forms. Unlike plant and fungi cells that have rigid cell walls, animal cells are bound by more flexible combinations of proteins. Most animals have cells organized into tissues and are able to move within their environment.

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The DVR brain region of birds displays similar neuronal organization and connectivity to the mammalian neocortex.

If you have ever been called “bird brain,” you know that it is not meant as a compliment. However, birds show that they know how to use tools, mimic human speech, and even grieve their dead. Simply put, birds are intelligent. Yet, their brains are still used as a benchmark for stupidity. This mismatch is understandable because their brains look so different from our own.

When people envision a mammal’s brain, they focus on the creased, gigantic structure known as the neocortex. It is the part of the brain that allows for creativity and flexible behavior and is even implicated in consciousness. Although birds do not have a neocortex, when scientists looked at the cellular organization of bird brains, they found a region called the dorsal ventricular ridge, or DVR, that shows neuronal connectivity similar to that in the neocortex of mammals.

In the mammalian structure, neurons are arranged into six layers of vertical columns which communicate with each other horizontally and vertically. This allows for more efficient and advanced mental processing. It was previously believed that the clumps of cells, called nuclei, that make up bird brains have less structure and organization than the layered mammalian cortex. However, it is now known that neurons within the DVR are arranged into layers and columns similar to mammalian brains. This suggests that the two regions may function similarly in both organisms.

The DVR boasts 0.5-2 billion neurons, which is significant when you compare it to the neocortices of other intelligent animals. Put simply, a greater number of neurons in the neocortex allows for better information processing. As a result, the number of neurons in the neocortex is the metric that humans use to claim their intellectual superiority over other animals. Humans have the most in the animal kingdom with approximately 16 billion neurons in their neocortices compared to 1-2 billion in advanced primates such as chimpanzees. The bird DVR, therefore, is on par with some of the most developed neocortices known.

This finding explains how birds can perform such advanced behaviors, proving that appearances can be misleading. The finding that the DVR has a similar structure to the mammalian neocortex, even while looking different to the naked eye, gives us a clearer view of the diversity of intelligence in the animal kingdom. And it presents an alternate model for the structuring of artificial networks as humans seek to improve the intelligence of built objects and systems.

Last Updated February 19, 2021

References

“I am generally not a big fan of ascribing complex humanlike cognitive states to animals and prefer to maintain a conservative attitude. Humans easily start to project their own mental states to other living (or even nonliving) beings. But in terms of sensory consciousness in other species, it is probably fair to assume that advanced vertebrates, such as mammals and birds, possess it.” -Andreas Nieder

Magazine article

Bird Brains Are Far More Humanlike Than Once Thought

Scientific American | September 24, 2020 | Bret Stetka

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Reference

“Mammals can be very smart. They also have a brain with a cortex. It has thus often been assumed that the advanced cognitive skills of mammals are closely related to the evolution of the cerebral cortex. However, birds can also be very smart, and several bird species show amazing cognitive abilities. Although birds lack a cerebral cortex, they do have pallium, and this is considered to be analogous, if not homologous, to the cerebral cortex.”

Journal article