March 8, 2005 | David F. Coppedge

If I Only Had a Brain…

The scarecrow didn’t know what he was asking for.  Look what Steven E. Hyman of Harvard says about the human brain and nervous system in the 8 March 2005 issue of Current Biology:1

The nervous system processes sensory information and controls behavior by performing an enormous number of computations.  These computations occur both within cells and between cells, but it is intercellular information processing, involving complex neural networks, that provides the nervous system with its remarkable functional capacity.  The principal cells involved in information processing are neurons, of which there are hundreds, if not thousands of individual cell types based on morphology, location, connectivity and chemistry.  In addition to neurons, the other major kind of cell in the nervous system is the glia, which play critical support roles, but which are increasingly seen to function in some aspects of information processing. [See 06/17/2003, 03/27/2001 and 01/29/2001 entries.]
    To provide some idea of the magnitude of the information processing capacity of the human brain, its 1011 neurons make, on average, about 1000 connections or synapses, at which communication occurs with other neurons.  The range of synapses per cell is very large; the Purkinje cells of the cerebellum may receive 100,000 contacts from input cells.  Overall the human brain may contain between 1014 and 1015 synaptic connections.2
    The diverse chemical substances that carry information between neurons are called neurotransmitters.  Otto Loewi discovered the first neurotransmitter in 1926 when he demonstrated that acetylcholine carried a chemical signal from the vagus nerve to the heart that slowed the cardiac rhythm.  Since that time, more than one hundred substances and a far larger number of receptors have been implicated in synaptic transmission…. Because of the remarkably diverse effects of neurotransmitter-mediated signaling at the receptor and post-receptor levels, the number of neurotransmitters, as large as it is, vastly understates the complexity of signaling in the brain. (Emphasis added in all quotes.)

Another article on EurekAlert announced that some neurons appear able to transmit three separate signals at the same time.  Hyman has a lot to say about information and signal processing, but not much about evolution.  For instance, he says:

The subtlety and complexity of the brain’s outputs, along with its ability to change in response to new information, is supported by a rich set of mechanisms for cell-cell communication involving at an anatomical level, intricate but plastic [i.e., adaptable] local connections, larger scale neural circuits and overlying global regulatory systems; and at the chemical level, a large number of neurotransmitters with highly diverse mechanisms for decoding their informational content.

In another paragraph he says, “Neurons are specialized to receive, process, and transmit information,” and describes how this is done chemically as well as electrically.  When it comes to explaining where this information came from, and how all this information processing complexity arose, he mentions the word evolution only once.  Because it is observed that some neurotransmitters serve multiple functions and are hard to classify, he concludes, “Unfortunately for those scientists with an intense need for simple classifications, evolution was a tinkerer that has reused signaling molecules to different effect in many different contexts.”


1Steven E. Hyman, “Magazine: Neurotransmitters,” Current Biology, Volume 15, Issue 5, 8 March 2005, Pages R154-R158, doi:10.1016/j.cub.2005.02.037.
2Dr. Walter T. Brown has calculated that this number vastly exceeds the number of all the electrical connections in all the appliances, computers and electronic devices on earth.

This article was so good until we hit the E word, we were going to really praise it to the hilt.  Forget his stupid last sentence for a moment and think of all that complexity working for you right now.  Think of all those connections – 100,000 per cell in some cases, all connected to neighboring cells not in a haphazard manner, but with purpose.  The proof is that it works: here you are, seeing, reading and thinking, while all this unfathomable amount of information processing going on inside that little 3-pound jelly-like mass in your skull.  Hyman seems almost beside himself describing the wonder of it, as he rightly should feel.  How on earth can he say this arrived by mindless, purposeless processes of evolution?  There is no way in a million universes that level of information could arise by chance, even from an ape-like ancestor (see 12/30/2004 entry), let alone from a primordial soup (see online book).
    “Evolution was a tinkerer,” he claims, thus personifying the favorite little Darwin Party goddess and proving that not even an evolutionist can be a consistent atheist.  Now we know who their ding-a-ling goddess is.  She gets the gong for her hopelessly inadequate impersonation of an intelligent designer.  It’s Tinker Bell.

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Categories: Human Body

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