Vertebrate brains have an outer layer of “gray matter” over the inner “white matter.” Why is this? “By borrowing mathematical tools from theoretical physics,” a press release from Cold Spring Harbor Laboratory announced, two researchers found out.
Posted on 01/14/2006 8:31:15 PM PST by bondserv
Why Your Brain Has Gray Matter, and Why You Should Use It 01/13/2006
Vertebrate brains have an outer layer of “gray matter” over the inner “white matter.” Why is this? “By borrowing mathematical tools from theoretical physics,” a press release from Cold Spring Harbor Laboratory announced, two researchers found out.
Based on no fewer than 62 mathematical equations and expressions, the theory provides a possible explanation for the structure of various regions including the cerebral cortex and spinal cord. The theory is based on the idea that maximum brain function requires a high level of interconnectivity among brain neurons but a low level of delays in the time it takes for signals to move through the brain. (Emphasis added in all quotes.)Their paper was published in PLoS Computational Biology.1 Despite the implicit deduction that the brain appears optimally designed, the authors looked to the random, unguided processes of evolution to explain how it got that way. Notice the first word in this next sentence: “Assuming that evolution maximized brain functionality, what is the reason for such segregation?” they asked. Did the claim of evolution ever get past the assumption stage?
Gray matter contains neuron somata, synapses, and local wiring, such as dendrites and mostly nonmyelinated axons. White matter contains global, and in large brains mostly myelinated, axons that implement global communication. What is the evolutionary advantage of such segregation? Networks with the same local and global connectivity could be wired so that global and local connections are finely intermixed. Since such design is not observed, and invoking an evolutionary accident as an explanation has agnostic flavor, we searched for an explanation based on the optimization approach, which is rooted in the evolutionary theory.Their use of the term agnostic is not what most people think (i.e., uncertainty about the existence of God), but a-gnostic, or “not knowing.” They recognize that saying it was a lucky accident is a non-answer. Rather, they assumed that evolutionary theory provides a pathway through the randomness toward optimization. They stated again that this was their starting assumption:
We started with the assumption that evolution “tinkered” with brain design [sic] to maximize its functionality. Brain functionality must benefit from higher synaptic connectivity, because synaptic connections are central for information processing as well as learning and memory, thought to manifest in synaptic modifications. However, increasing connectivity requires adding wiring to the network, which comes at a cost. The cost of wiring is due to metabolic energy required for maintenance and conduction, guidance mechanisms in development, conduction time delays and attenuation, and wiring volume.Sounds like a lot of engineering talk. The scientists assumed, but did not demonstrate in this paper,2 that natural selection was up to the task of yielding this optimized entity sometimes called the most complex assemblage of matter in the known universe.
Brains are mathematically perfect for achieving the sweet spot between maximized interconnectivity and minimized transmission delays. The authors reminded us that a human brain contains about 10 billion neurons, and that each one can contain thousands of connections with other neurons. The two-layer structure meets the competing requirements to a T. That part is amazing. Assuming that evolution did it earns this entry the Dumb award – really dumb.
Here again we are told about another apparition of the goddess of the Darwin Party, Tinker Bell. As the legend goes, she flitted aimlessly around the Cambrian swamps about 500 million years ago, zapping some emerging vertebrates with her mutation wand, killing countless myriads of them till one emerged lucky enough to have the beginnings of an optimized brain. As animals evolved, this process was repeated myriads of times more over millions of years, producing larger and more complex brains. Finally, at the end of the line, computational biologists emerged who could look back and analyze the whole process with abstract reasoning and mathematical equations, concluding that evolution had produced an optimized brain. Let us ask these true believers a simple question. If the brain evolved, how can you be sure of anything, including the proposition that the brain evolved? (From experience, we know that posing this type of question to a Darwinist is like putting a moron in a round room and telling him there is a penny in the corner.)
By assuming evolution at the outset, these computational evolutionists have provided as much insight into the origin of the brain as the vain mathematician did in the “assume we have a can opener” joke in the 12/17/2005 commentary. Their logic is as follows: Assume evolution produces optimized structures. An optimized brain would be structured so as to maximize interconnectivity and minimize delays. The brains we observe accomplish this by segregating highly-connected neurons in a gray matter layer and long axons in a white matter layer, thus fulfilling both requirements in an exquisite product that is the most complex device in the universe, that took us 62 simultaneous equations to describe. Isn’t evolution wonderful?
Undoubtedly this paper will be dutifully added to the growing corpus of scripture that the Darwin Party can hold up at school board meetings to show that the peer-reviewed scientific journals are filled with evidence for evolution, and that nothing in biology would make sense without it. Anyone raising his hand and saying, but to me, that looks like design would be quickly answered with, “Excuse me, we are talking about science here. If you want to change the subject to religion, go to church.”
Assumption is the mother of all myths. Perhaps you have heard the etymology of the word ASSUME: making an ASS (donkey) out of U and ME. Having gray matter is one thing. Using it is another.
I read science journals though I might think twice about the credibility of some of them after they published supposed peer-reviewed research of one Korean scientist. I always love how some think that one has to be credentialed from an Ivy League college before they can possibility participate in a dialog involving rational thought. Keep up the good work.
See post #78.
So we agree, it's random :)
Are these your good arguments?
Figure 1.4.4. Fossil hominid skulls. Some of the figures have been modified for ease of comparison (only left-right mirroring or removal of a jawbone). (Images © 2000 Smithsonian Institution.)
Thank you for your post.
I posted evidence. See #78 and #85, above.
That is evidence!
For forty years they were considered one of the archaeological finds of the century: A fragment of jaw and a part of a skull that could prove man evolved from the apes. They were the bones of Eoanthropus dawsoni found near Piltdown Common in Sussex. The bones of the "Missing Link."
Not.
Since 1953 the name "Piltdown" hasn't been associated with great scientific discovery, but great scientific fraud. It was in that year that a group of scientists, lead by Kenneth Page Oakley, attempted to use the new method of fluorine testing to get a more exact date on the bones. What the test showed surprised them: The jaw was modern and the skull only six hundred years old.
Additional analysis soon confirmed the fluorine tests. The jaw was really that of an orangutan. It had been filed down and parts that might have suggested it's simian origin were broken off. Both pieces had been treated to suggest great age.
Piltdown was proclaimed genuine by several of the most brilliant British scientists of the day: Arthur Smith Woodward, Arthur Keith and Grafton Elliot Smith. How did these faked fragments of bone fool the best scientific minds of the time? Perhaps the desire to be part of a great discovery blinded those charged with authenticating it. Many English scientists felt left out by discoveries on the continent. Neanderthal had been found in Germany in 1856, and Cro-Magnon in France in 1868. Perhaps national pride had kept the researchers from noticing the scratch marks made by the filing of the jaw and teeth. Items that were apparent later on to investigators after Oakley exposed the hoax.
Even as early as 1914, though, there were those that doubted the fossils. William King Gregory wrote, "It has been suspected by some that geologically [the specimens] are not old at all; that they may even represent a deliberate hoax..."
Who perpetrated the hoax? Many historians lay their bets on Charles Dawson, the amateur geologist that supposedly discovered the bones in a gravel pit. Others, though, lay the blame at the feet of people as diverse as a young Jesuit priest, named Teilhard de Chardin, who assisted in the dig, to the author Sir Arthur Conan Doyle, who lived in the area.
Dawson was an English solicitor who sought and collected fossils. Even before the find in Piltdown he was known as the "Wizard of Sussex" because of his many different and unusual finds. These included a prehistoric reptile, a mammal and a plant. Each boar a scientific name with dawsoni in it. Piltdown was his fourth: Eoanthropus dawsoni, "Dawson's Dawn Man," in Latin. If Dawson had lived longer this final discovery might have earned him a Knighthood. If the hoaxer was Dawson it looks like pride might have been his motive.
Probably the most telling evidence against Dawson is that, though he did not personally find all the Piltdown specimens, he appears to be the only figure around when each of the artifacts were discovered. Also, after his death in 1916, no more objects related to Piltdown were ever found despite the work of Arthur Woodward, a geologist at the British Museum, who continued to search Piltdown for fossils for many years after Dawson passed away.
There is some evidence that Martin A. C. Hinton, later the keeper of the zoology collection at the British Museum, may have prepared and planted the bones. In 1975 a steamer trunk, containing a set of bones stained the same way the piltdown fragments were, was found in the loft at the museum. The trunk is believed to have been owned by Hinton, and bears his initials. Two paleontologists at the museum, Brain Gardiner and Andrew Currant suggest that Hinton came up with the hoax to embarrass Woodward, who had refused Hinton a salaried job with the Museum. If this is true, then the hoax probably went alot further that Hinton had expected.
Dawson also, according to a friend, Samuel Woodhead, had an interest in stained bones and had "asked my father how one would treat bones to make them look older than they were..." The Piltdown bones had been stained with potassium bichromate.
We may never know for sure who perpetrated Piltdown. Dawson? Hinton? Or did they work together? There was never any confession and Dawson, as well as Hinton, are long gone now.
More from Richard Hartner's Piltdown Man Site.
Copyright Lee Krystek 1996. All rights Reserved.
Jack Chick Alert!
you posted no evidence, you only posted pictures with no connection in science, only in fictional fairy tales
The Nebraska Man Scandal
In 1922, Henry Fairfield Osborn, the director of the American Museum of Natural History, declared that he had found a fossil molar tooth belonging to the Pliocene period in western Nebraska near Snake Brook. This tooth allegedly bore common characteristics of both man and ape. An extensive scientific debate began surrounding this fossil, which came to be called "Nebraska man," in which some interpreted this tooth as belonging to Pithecanthropus erectus, while others claimed it was closer to human beings. Nebraska man was also immediately given a "scientific name," Hesperopithecus haroldcooki.
Many authorities gave Osborn their support. Based on this single tooth, reconstructions of Nebraska man's head and body were drawn. Moreover, Nebraska man was even pictured along with his wife and children, as a whole family in a natural setting.
All of these scenarios were developed from just one tooth. Evolutionist circles placed such faith in this "ghost man" that when a researcher named William Bryan opposed these biased conclusions relying on a single tooth, he was harshly criticized.
In 1927, other parts of the skeleton were also found. According to these newly discovered pieces, the tooth belonged neither to a man nor to an ape. It was realized that it belonged to an extinct species of wild American pig called Prosthennops. William Gregory entitled the article published in Science in which he announced the truth, "Hesperopithecus Apparently Not an Ape Nor a Man."235 Then all the drawings of Hesperopithecus haroldcooki and his "family" were hurriedly removed from evolutionary literature.
Faith: the belief in something for which there is no evidence or logical proof; acceptance of ideals, beliefs, etc., which are not necessarily demonstrable through experimentation or reason
Too often the evo's have faith in their ideas. But evidence proves them incorrect. They are still arguing that T-Rex was a scavenger not a hunter, but we have evidence of bones that have healed over with T-Rex teethmarks. One says he was too awkward and would have fallen over on the run. Others say he was an ambush kinda guy...
We have seen the Proof of the teeth marks yet some would believe otherwise.
Not exactly. I don't have a clue about cortex, nor do I particularly care about it as a topic of conversation. My comments were referring to the article, whose author seems to find it very significant. Apparently he thinks that it is not merely the presence of grey cortex or white cortex, but the certain features of the "networking". From the article:
(The theory is based on the idea that maximum brain function requires a high level of interconnectivity among brain neurons but a low level of delays in the time it takes for signals to move through the brain. Gray matter contains neuron somata, synapses, and local wiring, such as dendrites and mostly nonmyelinated axons. White matter contains global, and in large brains mostly myelinated, axons that implement global communication...What is the evolutionary advantage of such segregation? Networks with the same local and global connectivity could be wired so that global and local connections are finely intermixed...Brain functionality must benefit from higher synaptic connectivity, because synaptic connections are central for information processing as well as learning and memory, thought to manifest in synaptic modifications. However, increasing connectivity requires adding wiring to the network, which comes at a cost. The cost of wiring is due to metabolic energy required for maintenance and conduction, guidance mechanisms in development, conduction time delays and attenuation, and wiring volume.)
This piqued my interest, because the interconnectivity / signal delay time also come up as engineering tradeoffs in designing and programming parallel supercomputers, for anything except "embarassingly parallel" problems.
Assuming for the nonce that the quotes in the article are accurate, it appears that in humans one of the characteristics that differentiates grey from white matter is the quantity of global vs. strictly local connections between the brain cells. Is this true for all grey/white matter, or is the difference especially pronounced in humans? In other words, is this synaptic differentiation already present everywhere, and we just notice it in humans 'cause our brains are so much bigger than many other species? Or, is the difference in grey and white matter much more pronounced in humans?
If the second, then is the amount of differentiation smoothly varying from lower primate to higher primate up to man, or are there discontinuties, a "step function" in complexity at one or more points?
Are you talking about the time to transform a chimp-like brain into a human one? We have very good fossil evidence this transformation happened within 5-7 million years with most of it in the last three million. A chimp-like creature is a pretty good starting point from which to go in a human direction.
We have the skulls, but not the brain tissue, so unfortunately we can't dissect their brains to look at the degree of axonal connections, or axonal specialization, within different regions of the cerebral cortex. Sigh.
The point being, if you say, we have the fossils, so evolution MUST have done it, but without details of the mechanism, sounds like the "Energy makes it go!" from Feynman which I quoted earlier... The reason I say that is this. So far no one I've seen on this thread has come up with a specific set of environmental conditions, or changes, which would so strongly favor such large changes in intelligence over such a relatively short time. If we happened to know the details of the "engineering" details of the other primates, or (per impossible(*), the transitional forms, we might have a better idea of what specific changes were going on, and be better able to correlate them with the environment. Also, if we knew the exact genetic changes required to code for these changes in the brain, we could look at the number and location of the changes involved, and compare them to the basic mutation clock for DNA, to see if there was any "monkey business" (an outlier) going on.
If, OTOH, we just have the skulls and a few other indications, but we don't know in detail a physical mechanism, or a reasonable, specific set of environmental changes which would select for this growth without eliminating or supplanting related species (+), then just say, "we're not sure how, yet." We're all big boys (and girls) here; there was sufficient evidence (stoichiometry, conservation of mass, etc.) pointing to the atomic theory even before quantum mechanics was fleshed out.
Cheers! (*)[but you never know given the pseudo-fresh dinosaur bones :-) or the preservation of fresh-frozen mammoths :-) wink nudge semi-joking]
(+) If one assumes that the hominids leading up to homo sapiens shared geographical settings with the other primates, one might wonder whether such a huge survival advantage as conveyed by large brains would by mechanisms analogous to punctuated equilbrium supplant the "dumber" members even of other species. Three counterexamples to this supposition might be--first, that the humans were not in direct competition with many of the other primates, as their diets and specific environmental niche changed (humans don't live in trees and tend to hunt larger game); second, that humans originally eliminated some competing species within their environments , but not all; third, that humans eliminated some species, but then moved on, and the geographical areas which were originally denuded of competitors to humanity have been "back-filled" over time as humans moved on...
If one assumes that the hominids leading up to homo sapiens shared geographical settings with the other primates, one might wonder whether such a huge survival advantage as conveyed by large brains would by mechanisms analogous to punctuated equilbrium supplant the "dumber" members even of other species. Three counterexamples to this supposition might be--first, that the humans were not in direct competition with many of the other primates, as their diets and specific environmental niche changed (humans don't live in trees and tend to hunt larger game); second, that humans originally eliminated some competing species within their environments , but not all; third, that humans eliminated some species, but then moved on, and the geographical areas which were originally denuded of competitors to humanity have been "back-filled" over time as humans moved on...
A couple of points here.
First, there is the possibility that the larger brain did not evolve for intelligence as much as for better memory. Persistence hunting requires more memory than plucking fruits off the trees.
This leads into the second point. If the human-ape split began with a savanna group separating from a forest group when the forests contracted, with the savanna group changing in favor of hunting, then there is no direct competition for resources as (1) the territories are different and (2) the resources exploited are different.
Given this scenario, the real selection pressure would be on the savanna group, trying to make a living in a new territory. For the forest-dwellers it was business as usual.
Some posters ask why, if we descended from apes are there still apes? This scenario also addresses that question.
Note that what I am doing contradicts the oft-repeated charge that evolution (just like "Goddidit") predicts everything and explains everything. Under evolution, some things are a heck of a lot more likely than others. It's a far tighter hypothesis which might have been falsified in late 1859 or early 1860 but has not been yet.
For instance, the tree of life has to be a continuous, unbroken tree of common descent. Certain life forms have to have existed, whether we have found them in the fossil record yet or not. By comparison, creationists wave gaps around as evidence for separate creation, but finding yet another fossil filling a gap means nothing to a creationist except that now there are two gaps, one on either side of the new one.
The point being, if you say, we have the fossils, so evolution MUST have done it, but without details of the mechanism, sounds like the "Energy makes it go!" from Feynman which I quoted earlier...
The fossil record won't give you molecular data on anything back very far. You can say what the cranial capacity is by such-and-such a time, size of the Broca's area, etc. You may have some evidence for tool-making, ceremonial burial, or not. But you have extant branch tips and their molecular differences, so it's not a total loss. I see no point in not studying what you have because of what you don't.
Also, it's pretty crazy to pretend something didn't happen because you can't reconstruct exactly in a mutation-by-mutation historical scenario how it did when you have quite a lot of evidence that it did, a general theory of how such things occur, and evidence that evolutionary changes have happened repeatedly and are happening now.
The cortex-stem brain architecture (subject of the actual study being word-lawyered by C-E Headlines) is basic to vertebrates. The evolution of human-ape brain differences is utterly a different topic, really.
Nonsense. You clearly have not tried poetry, literature, theology or philosophy.
LOL, this is a really good joke, and it is probably invisible to all the math-challenged.....(!)
(I just can't imagine big numbers like 1 to the power of infinity!)
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