Clever Corvids: the cortical equivalent in many birds (Introduction)

by David Turell , Thursday, September 24, 2020, 22:28 (1521 days ago) @ David Turell

The Avian equivalent of our brain's cortex does exist:

https://science.sciencemag.org/content/369/6511/1567?utm_campaign=toc_sci-mag_2020-09-2...

"birds, and particularly corvids (such as ravens), are as cognitively capable as monkeys (1) and even great apes (2). Because their neurons are smaller, the pallium of songbirds and parrots actually comprises many more information-processing neuronal units than the equivalent-sized mammalian cortices.

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"Birds do have a cerebral cortex, in the sense that both their pallium and the mammalian counterpart are enormous neuronal populations derived from the same dorsal half of the second neuromere in neural tube development

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"In both birds and mammals, the pallium is the population of neurons that are not a necessary part of the most fundamental circuits that operate the body. But because the pallium receives copies, through the thalamus, of all that goes on elsewhere, these pallial neurons create new associations that endow animal behavior with flexibility and complexity. So far, it appears that the more neurons there are in the pallium as a whole, regardless of pallial, brain, or body size, the more cognitive capacity is exhibited by the animal. Humans remain satisfyingly on top: Despite having only half the mass of an elephant pallium, the human version still has three times its number of neurons, averaging 16 billion. Corvids and parrots have upwards of half a billion neurons in their pallia and can have as many as 1 or 2 billion—like monkeys.

"Additionally, it has been known since 2013 that the circuits formed by the pallial neurons are functionally organized in a similar manner in birds as they are in mammals (10). Using resting-state neuroimaging to infer functional connectivity, the pigeon pallium was shown to be functionally organized and internally connected just like a mouse, monkey, or human pallium, with sensory areas, effector areas, richly interconnected hubs, and highly associative areas in the hippocampus and nidopallium caudolaterale. The nidopallium caudolaterale is the equivalent of the monkey prefrontal cortex (10), the portion of the pallium that is the seat of the ability to act on thoughts, feelings, and decisions, according to the current reality informed by the senses.

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"...the same is true of consciousness: The underpinnings are there whenever there is a pallium, or something connected like a pallium, with associative orthogonal short- and long-range loops on top of the rest of the brain that add flexibility and complexity to behavior. But the level of that complexity, and the extent to which new meanings and possibilities arise, should still scale with the number of units in the system. This would be analogous to the combined achievements of the human species when it consisted of just a few thousand individuals, versus the considerable achievements of 7 billion today".

Comment: We knew birds were smart, and now we know why. Part of me is very interested in the bolded comment at the end. Hominins and homos were in small population numbers before we advanced 50,000 years ago and began to build a large population. This fits Gould's concept of small isolated populations causing rapid or large evolutionary advances. What is weird is that a small population is like to have less mutations than a large population, but large brains appeared anyway. That support the concept of a driving force like God. The other point is it is teh volume of neurons that make a difference. Size, by itself, is not a major guide to brain capacity as the first bold shows.