Bird Brain – a Myth….

Bird Brain – a Myth….

Think birds can’t have much intelligence because of that small brain size? Think again. We have four parrots who continually surprise us with what we view as intelligence so this subject fascinates us.

Several years ago I attended an interesting lecture at the San Diego Museum of Natural History featuring neuroscientist Dr. Harvey Karten (U California – San Diego) entitled “Bird Brains.”

I got the following from his lecture and a more recent press release on his research (See UCSD bird brain article )

  • What’s smart? Karten began the lecture by saying to watch what you mean by ‘smart’ – a hummingbird hovering in place in a 50 mph wind isn’t smart?
  • Cortex is not all it made out to be: Remember how we’ve been taught that our mass of gray matter (the neocortex) separates us from other animals. According to Karten, it’s overblown. Way overrated. Because — birds and fish have the same neurons, they’re just found in different areas of the brain (the bird brain’s DVR – see below for more detail*)
  • More similarities than differences: He called the similarities in sharks, reptiles, fish, birds ‘outstanding,” saying, “We’ve found similarities where none were expected to exist…. We’re having more trouble finding differences than similarities.”

The ratio of brain size to body size is the same in birds as in mammals.

The Takeaway: The circuitry of our brain and its underlying complex behaviors are common to many vertebrates. Research shows birds (and fish) have the same neuron circuitry; it’s just located in a more ancient part of the brain.

See below for more info on the high intelligence of many bird species – and fish and reptiles.

Bird Intelligence Resides in the DVR (dorsal ventricular ridge) 

Findings of Harvey Karten & other neurobiologists:

  • Our brain (and other mammals) features layers of cells that connect in columns to form neurons and specific connections – the circuitry that allows the click, click thinking of our brains. Non-mammals brains (fish, reptiles, birds) have no similar arrangement.
  • Karten’s research (which he’s worked on for 40 years now) shows the bird’s circuitry is preserved in a structure called DVR (dorsal ventricular ridge), not the cortex. Basically, things we thought were novel to humans have been around for many years. In mammals, this DVR migrated into our cortex – and this is why the brain size of mammals increased.
  • Birds have the same % of microcircuitry as mammals do, but in their DVR. Their measurements show the ratio of brain size to body size is the same in birds as it is in mammals.
  • To help answer the complex circuitry of the human brain came from and when did it first evolve, Karten mapped a region of the chicken brain that handles listening, similar to the mammalian auditory cortex. What he found was this section was virtually identical to those found in the mammalian cortex.

SO – these properties of the neocortex do NOT appear unique to mammals, and may in fact have evolved from cells and circuits in much more ancient vertebrates. The computational microcircuits underlying complex behaviors are common to many vertebrates.

 

About Linda Richards

My goal is to educate about the science of nature in layperson speak, through my writing, science and education background. I grew up in the Chicago area, loved living in Minneapolis before gravitating to the West, which is now home.

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