January 24, 2008 | David F. Coppedge

Getting a Hand on Facts and Meanings

What could be more simple than pressing a button with your finger?  That “seemingly trivial action is the result of a complex neuro-motor-mechanical process orchestrated with precision timing by the brain, nervous system and muscles of the hand.”  So says a press release from University of Southern California posted on EurekAlert.
    Simple, everyday acts we perform without thinking: cracking an egg, typing on a keyboard, fastening a button, fumbling with a cell phone to answer a call – all require a sophisticated coordination and messaging system between the brain, the nervous system and 30 muscles of the hand.  Francisco Valero-Cuevas of USC’s Viterbi School of Engineering commented, “we don’t understand well what a hand is bio-mechanically, how it is controlled neurologically, how disease impairs it, and how treatment can best restore its function.”
    In an effort to begin to understand, Valero-Cuevas and Madhusudhan Venkadesan, a mathematician from Cornell, measured electrical activity of the muscles of the hand when students simply pressed a surface with a forefinger.  Seven muscles of the forefinger clearly switched from a “motion” mode to a “force” mode 65 milliseconds before impacting the surface.  “Venkadesan’s mathematical modeling and analysis revealed that the underlying neural control also switched between mutually incompatible strategies in a time-critical manner.”  This is a “neurally-demanding” transition even for such a trivial act.  The brain must be planning the transition ahead of time, because there is a finite amount of time required to activate the muscles.  “Neurophysiological limitations prevent an instantaneous or perfect switch,” Valero-Cuevas said, “so we speculate that there must be specialized circuits and strategies that allow people to do so effectively.”  Imagine, he said, going through life with winter gloves on.  That’s how life would be without these systems.  Our ability to perform fine manipulation of objects with our fingers is a result of many parts working together in precise ways.
    What does all this mean?  For one thing, it explains why it takes years of training for children to master precision skills with their fingers like pinching and manipulating objects, and why these skills can be lost with neurological diseases and aging.  “But perhaps even more importantly,” he said, “the findings suggest a functional explanation for an important evolutionary feature of the human brain: its disproportionately large sensory and motor centers associated with hand function.
    Valero-Cuevas marched seamlessly from observations in the present to speculations about prehistory. 

If, indeed, the nervous system faced evolutionary pressures to be able to anticipate and precisely control routine tasks like rapid precision pinch, the cortical structures for sensorimotor integration for finger function would probably need to be pretty well developed in the brain,” Valero-Cuevas said.
    “That would give us the neural circuits needed for careful timing of motor actions and fine control of finger muscles,” he said.  “Thus, our work begins to propose some functional justifications for the evolution of specialized brain areas controlling dexterous manipulation of the fingertips in humans.”
    The article was also posted by Science Daily on Jan. 28.

The article changed subjects at this point and talked about possible medical applications of their biomechanical research.  For some reason this story was unreachable on the USC website.  The title was present, but the link was broken.

For three sins of USC, and for four, the reprimand due these scientists will not be turned back.  (1) Disjunction: There is no connection between the observed facts and their evolutionary story.  They made it up out of thin air with hand-waving and magic.  (2) Misrepresentation: It misrepresents evolutionary theory.  Needs to do not produce complex structures.  “Evolutionary pressures” do not “give” the “neural circuits needed” to provide precision switching and control of 30 muscles to perform fine manipulations of objects.  The only evolutionary pressure is the one to go extinct.  Unless random mutations appear, the pressure is toward death, not emergence of complex, interacting systems.  (Good luck waiting ten to the quintillion years for that to happen.)  (3) Deception: By presenting an evolutionary explanation as incontrovertible fact, they are lying to the public and their students.  What they saw was engineering design, not evolution.  OK, strike three; but since creationists are longsuffering and merciful, one more chance.  Whoops: (4) Ingratitude: Can any sin be more egregious than to be handed a gift, like two hands and ten fingers, and then to use them against the Giver?
    The observational facts of science do not support evolutionary storytelling.  You saw it just now.  These researchers looked at raw, empirical evidence for fine-tuned complexity, and even admitted they don’t understand it, but then immediately leaped into Fantasyland to claim with brashness and confidence that it evolved.  They get away with it because that is all they have ever been trained to believe, and critics are systematically expelled from the discussion.  Philosophers who should be blowing the whistle on these unwarranted assertions are too often cowed into timidity by the temerity of the Darwin Party.
    Until scientists realize that such philosophical inferences are unfounded – that they are contrary to the purpose and reasoning of science – the debate over creation and evolution will be muddled in noise.  It is not the job of the scientist to invent a tale about a mythical past he cannot observe even in principle.  Stick to the facts.  Get a grip.  Press here.  Then, and only then, can people with sense discuss what the facts mean.


Encore:  To reinforce the conviction that brain/hand coordination could never have evolved, listen to a recording of Vladimir Horowitz playing Rachmaninoff’s Piano Concerto No. 3.  Horowitz performed nearly 30 minutes entirely from memory, over a huge dynamic range with such rapid-fire precision it is incredible to conceive of the brain signaling involved.  Can you imagine a chimpanzee doing this?  Or composing such a thing?  For a sample, here is part of the second movement on YouTube.  You absolutely must hear the third and final movement.  Here is a taste on YouTube, which, unfortunately, stops before the grand finale.  A poorer-quality video that includes the ending can be found at truveo.com.  If you liked these, here’s another fast finger frolic.  How about one more?  Go ahead, Charlie; tell me about evolution.

(Visited 11 times, 1 visits today)

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.