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. Isnt 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.
It's also evidence that these teeth are like those of dinosaurs, not like those of mammals, fish, or amphibians.
It is an observed fact that no modern bird has teeth.
So, an obvious question would be, "why do birds have unexpressed genes for dinosaur-like teeth?"
There are enough fossils that are hard to classify as "birds with teeth and bony tails" or as "dinosaurs with feathers" to make for an obvious answer.
...Variations within kinds are possible and it involves loss of information not gaining. So having the gene that does not produce the product is not evolving, or evidence that it was a lizard..
I'm not a "baraminologist", so please spell out what the "kinds" are in this discussion.
It's also not at all obvious that there was a loss of information here; all that's been observed is that some genes aren't expressed. So the information needed to make teeth wasn't lost. All we can say is that it is isn't used - this could easily be because of more information, in the form of new genes actually turning the development of teeth off.
Why isn't this evolution? If there were birds with teeth, and those without, living today, wouldn't they be classified as different species? Again, you're going to have to be specific about what "kinds" refers to here.
Summarizing. I do consider this experiment as showing that ancestors to hens had teeth. And I do consider the presence or absence of teeth as sufficient difference to call the ancestor and the modern forms different species. Hence, an example of evolution.
"It's always the beginning assumption; then they look for a way to make the pieces fit, no matter how tortured a path it requires."
We always got in trouble for working backwards from the answer in math class. For them it seems like the standard method.
"missed a period" placemarker
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