Fernando García-Moreno
Appearances
Short Wave
How Nature Makes A Complex Brain
the hippocampus which is in charge of memory, for instance, memory processing, or the amygdala which is in charge of emotional processing.
Short Wave
How Nature Makes A Complex Brain
So for some researchers, they thought that the same cell types appearing in the neocortex are located in a different manner, not in layers, but in nuclei, in birds, for instance. they tend to think this because all these neurons communicate each other in a quite similar fashion.
Short Wave
How Nature Makes A Complex Brain
We found that the pallium of all the structures develops in the embryo following different rules. So the areas in the brain in which these neurons are generated for the pallium or the timing in which these neurons are generated, it is strictly different when we compare reptiles to mammals or to birds.
Short Wave
How Nature Makes A Complex Brain
Yeah, we cannot research the brain of these animals who are extinct for 300 million years, but it allows us to hypothesize how the brain of these animals were. And we think that it shows us how the brain of the last common ancestor was organized in terms of palatal neurons and palatal circuitry. So we think that the same equivalent circuits that we see today
Short Wave
How Nature Makes A Complex Brain
in different areas of the pallium were present in the last common ancestor, not present in, for instance, in the case of amphibians. But they must be present in the last common ancestor because all amniote species, mammals, reptiles and birds evolved circuits from them.
Short Wave
How Nature Makes A Complex Brain
Definitely these were simpler circuits, much simpler than the ones that we can see today, but we think that the last common ancestor already had some of them in the Paleo. So what we see is that this circuit is very relevant, its features, because it has been selected several times in evolution.
Short Wave
How Nature Makes A Complex Brain
And we think that for people trying to research connectomics and also to make artificial intelligence or artificial neural networks, they should consider how this circuit acts because it is the most efficient and the optimal one selected by evolution. So we should not reinvent the wheel when nature is telling us this is the efficient circuit.
Short Wave
How Nature Makes A Complex Brain
Convergent evolution means that two features in two independent animals have evolved separately, but they have reached the same feature. It's the same characteristics. So the classic example is the wings of bats, butterflies, and birds. So when you research them, you can see that they develop in a completely different fashion.
Short Wave
How Nature Makes A Complex Brain
So bats are making the wings with their fingers, whereas birds, they're doing it with the whole arm, for instance. And insects, they're doing it with some different primordia in the embryo. So we know that they are convergent because if we go to the common ancestor to these three animals, it was kind of a worm that didn't have any wing and didn't have even limbs.
Short Wave
How Nature Makes A Complex Brain
So we know that the wings of these species, they have evolved separately. They are not inherited from a common ancestor. But then we know that they are fulfilling the same function and therefore they have a very similar structure. Because to fly, you need a wing which is in this fashion, with a particular surface, particular thickness or weight.
Short Wave
How Nature Makes A Complex Brain
So function, because it was common, you need to fly, dictated the shape of wings in all these species. In the case of these circuits, we consider they evolved in a convergent manner, because although they follow different evolutionary routes, they ended up generating circuits which are very similar.
Short Wave
How Nature Makes A Complex Brain
There is something quite relevant, which is intelligence, for instance, or the highest sensorial processing, have appeared several times in evolution. So we are not just an example of something very unique and special. Intelligence is not such unique and special. We think that complex brain and complex cognitive tasks
Short Wave
How Nature Makes A Complex Brain
have evolved separately several times because the circuits and the neurons in charge of them have evolved several times and separately. So for instance, birds, some birds can count.
Short Wave
How Nature Makes A Complex Brain
Yeah, exactly. And they are doing it with different parts of the pallium. Of course, the pallium is involved, but different parts of the pallium are in charge or making the sounds, for instance, or the motor control of the larynx and the tongue, this kind of thing. But the neurons and the areas of the pallium are different. So human intelligence or mammalian intelligence is not unique.
Short Wave
How Nature Makes A Complex Brain
Other species evolved intelligence and complex cognitive tasks through other neurons and different neurons and separately evolved.
Short Wave
How Nature Makes A Complex Brain
But it already had some specializations, like a different skin, specialized lungs, or brains, etc.
Short Wave
How Nature Makes A Complex Brain
We think so because we are using different structures and different types of neurons to be this kind of intelligence. So bird brains are amazing. A couple of examples. So they have evolved to fly and therefore they have secondary specializations. And the most important in this case and the pain in the neck for us in the lab, is that they have reduced enormously the size of neurons.
Short Wave
How Nature Makes A Complex Brain
So they are tiny. In this way, they can reduce the size of the brain and the weight of the brain. The whole brain and the whole body of birds is designed to weigh very low. so they can fly. The neurons in bird brains are tiny, and they are thoroughly compacted, so these are the most dense, in terms of neurons, the most dense brains in nature.
Short Wave
How Nature Makes A Complex Brain
But also, when you compare the number of neurons, which always, or classically, was considered a correlation to intelligence, Some birds, they have double the number of neurons of a primate of the same size. So they have huge numbers of neurons. Definitely, these are very clever animals and they are differently clever to us.
Short Wave
How Nature Makes A Complex Brain
I have to say that I am the least anthropocentric person in research, biology.
Short Wave
How Nature Makes A Complex Brain
Yeah, definitely. So I'm extending my low anthropocentric view. I am also very low mammalocentric view. So we see in the lab a lot of complexities in other brains. So we also, I don't do research directly on human brains.
Short Wave
How Nature Makes A Complex Brain
But I tend to think that in the last 25 years since I've been working in labs, there is a paper coming out every two, three years claiming that there is a specific feature to humans. It could be a cell type which only appears in humans or a circuit that is only developing in humans. But then after three, four years, someone finds the same circuit or cell type or progenitor type in primates.
Short Wave
How Nature Makes A Complex Brain
And then someone else finds it five, ten years later in mice. So in the end, me as the least anthropocentric researcher ever, I tend to think that our brain is special in quantitative features, but not in qualitative features. So we are a mammalian brain, definitely this is different to a bird brain, but we just have more of the same units.
Short Wave
How Nature Makes A Complex Brain
And there might be an emergent property coming up from this increase in the number. But I don't believe someone has convincingly sold cell types which are specifically human or connections which are specifically human. In the case of birds, they can count and they can plan the future. As you said, they can make tools on their own. They can... hide some... Like food?
Short Wave
How Nature Makes A Complex Brain
Some food or something for the future, this kind of thing. So they can plant, but they are doing it with a different part of the polyp. Wow.
Short Wave
How Nature Makes A Complex Brain
The main takeaway is that humans are special, but so are birds and reptiles. So our brains are amazing. but bird brains are even as amazing at least. We have neurons other species do not have, but the chicken, even the chicken, stupid chicken, they do have neurons that we don't have.
Short Wave
How Nature Makes A Complex Brain
So evolution has found so many different ways to generate complex brain, not just only one direct pathway from amphibians to humans. In this case, the tree of intelligence is just a tree. It's not just a single branch in the case of mammals.
Short Wave
How Nature Makes A Complex Brain
In every case, in all the species, the pallium is in charge of high task and high hierarchical tasks, such as cognitive processing, sensorial processing, motor control, also language, for instance, in the case of mammals and birds.