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The Human Brain

Discussion in 'Creation vs. Evolution' started by Administrator2, Jan 22, 2002.

  1. Administrator2

    Administrator2 New Member

    Jun 30, 2000
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    This is from a secular source no less!

    The brain is one of science's final frontiers. We know very little about how it functions. "We are like Martians looking at a car," says one neuroscientist. "We've driven the car, and we've taken the car apart, but we don't know how one part is related to the other."

    The human brain consists of some 10 billion neurons and 60 trillion synapses communicating through an elaborate system of electrical and chemical signals. After 30 years of poking and prodding, we yet do not understand why we can remember 10 telephone numbers easily, but not 100. Nor do we have a clue as to how we recognize faces so effortlessly.

    We do know that tiny aberrations in the cerebral cortex can lead to schizophrenia -- or endow us with an amazing ability to factor huge numbers, memorize the telephone book, or perceive smell as vividly as a dog does. How this happens remains a mystery. We not only lack a good map of the brain's topography, a number of studies done in the 1980s suggest that each brain may have unique circuitry. That would indicate that memory and language are "wired" differently from person to person.

    In 1982, the Defense Department wanted to build a computer to evaluate brain function, but the technology at the time was inadequate to do the task. Once functional magnetic resonance images (fMRI) were introduced in 1991, neurologists could study the connections between different parts of the brain. A fMRI shows which parts of the brain are activated by different types of physical sensation or activity, such as sight, sound or the movement of a subject's fingers. Other advances in neurotechnology also shed light on how the brain functions.

    Magnetic resonance imagery (MRI), positron emission tomography (PET) scanners, and optical and electromagnetic signal imagers now allow researchers to view brains down to their synapses. In addition, transcranial magnetic stimulators can zap areas of the brain with magnetic pulses. Sent through the skull, these pulses cause a subject to see flickering lights or experience twitches. Some pulses are currently being used to treat depression.

    In 1993, The National Institute of Mental Health and four federal agencies funded the world's largest neuroscience project. Known as the Human Brain Project, its goal is to build an omni-dimensional, computerized database that synthesizes all neurological research -- from the shape of synapses up through chemistry and gross anatomy.

    Nearly 200 research scientists are involved at 19 universities and 6 hospitals in 10 countries. One of the Project's first goals is to build a map that quantifies the range of variation in the brain. (This will determine whether individuals really do think differently.)

    The initial data gathering for brain mapping ended last October. Some 7,000 volunteers submitted to 50-minute anatomical MRI tests, and 5,800 of them provided DNA samples. This summer, 1,000 of these volunteers will take nine fMRI scans to map brain function. The scans will join 100 terabytes of brain data already in storage. Whether this database will "somehow naturally sort itself out in a way that's helpful (is) a complete shot in the dark," according to neural science professor Tony Movshon of New York University.

    As computing power increases, so does activity at the Human Brain Project. Before 1993, the enormous volume of data required to understand the brain would have swamped existing computational and storage resources. The 3-pound organ contains more possible neural pathways than there are atoms in the visible universe.

    Sequencing the human genome is a trivial task compared to creating a database for the human brain. There are levels of complexity to the brain that are not even remotely comprehended -- not too surprising in an organ capable of 20 million billion calculations per second.

    Self-consciousness arises from this tangle of ultra-high-speed computation, but we do not know which of the billion-billion-billion possible pathways combine to create it. The human brain is a superparallel electrochemical computer that is highly dependent upon specific timing and connection patterns. Disrupt circuits or timing and dramatic things happen -- like being unable to read the words on a page or recognize oneself in the mirror.

    The current phase of The Human Brain Project is designed to determine whether there is a general similarity in brain "wiring" and responsiveness between individuals. The 1,000 volunteers undergoing fMRI (functional magnetic resonance image) tests will don virtual reality goggles and repeat a series of exercises while brain activity is recorded.

    A series of objects will be projected in the VR goggles -- a nose, a chicken, a cigarette, a deer, a ladder, a squirrel, a shirt, and a goat. After 30 seconds, the test stops, and a small black cross serves as a control to help sift out attention effects. While the subject concentrates on the cross, background "noises" (heartbeat, fleeting thoughts, sounds, sensations, etc.) are filtered out of the test images.

    Initial results from a verb-association test done in 14 languages indicate that similar portions of the brain light up each time a subject is tested. This provides evidence that at least some functions are universal and appear in the same location. This is collaborated by case histories of people with brain injuries. In prosopagnosia, a disorder that leaves individuals able to recognize everything except faces, similarly located brain lesions appear. This leads researchers to believe that there is a region reserved for recognizing human faces.

    Searching a brain for anatomical anomalies could be helpful. Some psychiatrists associate schizophrenia, for example, with asymmetry in an area near the front of the cortex called the anterior cingulate gyms (ACG). A box drawn around the ACG of a normal brain is always wider than it is high. In schizophrenia, the box is taller than it is wide on the left side -- the side that controls attention processes.

    Fixing malfunctioning brains is a big part of brain research, "but there is a whole untapped world of taking normal brains and trying to make them really good", says the director of UCLA's Brain Mapping Center. "We have some tools now that might improve the capacity of our nervous system."

    Neurologists are decades away from optimizing the brain with precisely directed electric pulses. In fact, they may never succeed. Although mathematical warping algorithms can overcome anatomic variability, it is possible that only some basic functions will map to specific brain regions. It is not clear whether higher functions will be easy to locate, much less generalize.

    There are huge mathematical problems involved in locating the source of brain signals. A fMRI scan, for example, measures blood oxygen, not neural firing. Blood oxygenation levels are recorded over seconds, but neurons fire in milliseconds. Since a fMRI shows an averaged-out blob of activity, it has to be combined with a different scanning technique for accurate spatial and temporal resolution. One approach is to include an EEG (electroencephalogram) which measures electrical activity in milliseconds (but does not locate signal sources precisely.)

    While the new imaging machines are revolutionary, their use to map the brain is questioned. "To a certain degree, this is modern phrenology," says the director of UCLA's Imaging Lab. "We're looking at shapes and structures in the brain and claiming they mean something. Not long ago, we were feeling the bumps on people's skulls and claiming the same thing."

    *** END ***

    Let's Make Your Head Interactive, Wired, August; Review by A. J. Vendeland

    Some would have us believe that random chemical processes and natural selection produced the human brain.

    I praise you because I am fearfully and wonderfully made; your works are wonderful, I know that full well. (Psa 139:14 NIV)

    There is a quote I love to use from Richard Dawkins himself right out of "Blind Watchmaker" on this subject. All you have to do is read it and you will see why I love to use it. It is not that famous opening line, but it is in the preface -- the first two paragraphs:

    This book is written in the conviction that our own existence once presented the greatest of all mysteries, but that it is a mystery no longer because it is solved. Darwin and Wallace solved it, though we shall continue to add footnotes to their solution for awhile yet. I wrote the book because I was surprised that so many people seemed not only unaware of the elegant and beautiful solution to this deepest of problems but, incredibly, in many cases actually unaware that there was a problem in the first place!

    The problem is that of complex design. The computer on which I am writing these words has an information storage capacity of about 64 kilobytes…. The computer was consciously designed and deliberately manufactured. The brain with which you are understanding my words is an array of some ten million kiloneurones. Many of these billions of nerve cells have each more than a thousand 'electric wires' connecting them to other neurones. Moreover, at the molecular genetic level, every single one of more than a trillion cells in the body contains about a thousand times as much precisely-coded digital information as my entire computer. The complexity of living organisms is matched by the elegant efficiency of their apparent design. If anyone doesn't agree that this amount of complex design cries out for an explanation, I give up. No, on second thoughts I don't give up, because one of my aims in the book is to convey something of the sheer wonder of biological complexity to those whose eyes have not been opened to it. But having built up the mystery, my other main aim is to remove it again by explaining the solution.

    The answer, of course, is evolution. That thing we can't even get E.coli to do in a couple of million generations.

    But it gave us our brains!

    It's hard to believe anyone with any education and/or common sense could fall for that, isn't it?