We’ve all heard how we supposedly use only 10% of our brains. I’ve always thought that meant there was some latent higher structure in our brains we just needed to figure out how to tap into. I really never questioned that assumption until now, and it doesn’t make sense from an evolutionary perspective why the brain would be hyper-developed relative to our present use of it; the reality is even more fascinating.
The excerpts below from an article in this month’s Discover Magazine Entitled “The Dark Matter of the Human Brain” by Carl Zimmer raises the question: If there are in the brain cells which outnumber neurons 10:1 and which code and transmit information via biochemical transmission rather than by electric transmission as in neurons, can it be said that the brain has in reality two information systems at work? Zimmer uses the analogy of the Astrocytes as an analog network and the Neurons as a digital network. We know from our experience with the evolution of computers that both analog and digital networks have their own pros and cons. The question in terms of the Brain is why are there both? Does one pre-date the other in the evolutionary timeline? Do their functions overlap or are they distinct?
One interesting suggestion mentioned below is that the analog network of Astrocytes may be responsible for “our creative and imaginative existence as human beings.” As with technology, while the digital experience conveys more information more quickly with far less physical structure, there will always be a quality inherent in analog transmission which digital lacks. The nature of the digital transition via discrete packets of distinct quanta, however complex, can never match the continuity and depth of analog waves in their richness and tone. Of course, the drawback to analog as we know from the example of television is that the picture on your analog TV is merely an imperfect representation or approximation of the original source, while a digital picture is an exact replica of the original.
If we take this metaphor one step further can we suppose that the brain utilizes its Astrocytes analog network in such activities such as memory and emotion, where the natures of those activities are by definition representations? Can we then suppose that the digital network of neurons could be responsible for activities in the brain which are more exact and rapid such as computation and reasoning?
Granted this is a blatant oversimplification of an area of brain science which is not yet fully understood, however the presence of these two systems in the brain could go along way in our understanding of the supposed duality of human experience.
Meet the forgotten 90 percent of your brain: glial cells, which outnumber your neurons ten to one. And no one really knows what they do.
By Carl Zimmer
“Astrocytes—named for their star like rays, which reach out in all directions—are the most abundant of all Glial Cells and therefore the most abundant of all the cells in the brain. They are also the most mysterious. A single astrocyte can wrap its rays around more than a million synapses. Astrocytes also fuse to each other, building channels through which molecules can shuttle from cell to cell. …Astrocytes, like neurons, can react to neurotransmitters—but instead of electricity, the cells produce waves of charged calcium atoms.
…(Astrocytes) have at least some of the requirements for processing information the way neurons do. Alfonso Araque, a neuroscientist at the Cajal Institute in Spain (found) that two different stimulus signals can produce two different patterns of calcium waves (that is, two different responses) in an astrocyte. When they gave astrocytes both signals at once, the waves they produced in the cells was not just the sum of the two patterns. Instead, the astrocytes produced an entirely new pattern in response. That’s what neurons—and computers, for that matter—do.
If astrocytes really do process information, that would be a major addition to the brain’s computing power. After all, there are many more astrocytes in the brain than there are neurons. Perhaps, some scientists have speculated, astrocytes carry out their own computing. Instead of the digital code of voltage spikes that neurons use, astrocytes may act more like an analog network, encoding information in slowly rising and falling waves of calcium. In his new book, The Root of Thought, neuroscientist Andrew Koob suggests that conversations among astrocytes may be responsible for “our creative and imaginative existence as human beings.”
There is something marvelous in the fact that we barely understand what most of the cells in our brains are doing. Beginning in the 1930s, astronomers realized that all the things they could see through their telescopes—the stars, the galaxies, the nebulas—make up just a small fraction of the total mass of the universe. The rest, known as dark matter, still defies their best attempts at explanation. Between our ears, it turns out, each of us carries a personal supply of dark matter as well.”