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Neurologically We're Just Zombies

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  • medit8ionsociety
    By better understanding the zombie within, neurobiologists hope to explain consciousness By Scott LaFee UNION-TRIBUNE UNION-TRIBUNE STAFF WRITER March 24, 2004
    Message 1 of 1 , Mar 25, 2004
      By better understanding the zombie within, neurobiologists hope to
      explain consciousness
      By Scott LaFee
      March 24, 2004
      For most people, the prototypical zombie is a Hollywood creation, a
      walking dead guy oblivious to everything, utterly unresponsive to any
      stimulus other than its insatiable hunger for human flesh.
      Such zombies – if they actually existed – would be easy to identify:
      slack jaws, hollow, empty eyes, a body in an advanced stage of
      decomposition. Real-world zombies, though, are even easier to spot.
      They look exactly like you, me and everybody else.
      That's not to say, of course, that any of us actually suffers from
      cannibalistic cravings. Rather, as humans – indeed because we are
      humans – we often behave like zombies. That is, we tend to live beyond
      the pale of consciousness.
      Consciousness is one of the great and lingering mysteries of science.
      Francis Crick, the Nobel laureate who co-discovered the structure of
      DNA, calls it "the major unsolved problem in biology."
      Crick, who has spent the last couple of decades at the Salk Institute
      in La Jolla conducting brain research, believes that all of the
      brain's behaviors, including consciousness, result from the brain's
      physical processes. For more than a decade, he and colleagues like
      Christof Koch, a neurobiologist at the California Institute of
      Technology in Pasadena, have argued that human self-awareness is
      essentially the consequence of countless neurons, sensory cells and
      other physiological systems interacting with the environment to create
      the intangible entity we know as our minds.
      Everything we think, say and do, contend Crick and Koch, can be
      explained biologically. It is their ambition to prove it, to find what
      they call "the neuronal correlates of consciousness."
      And that's where zombies come in.
      Living on autopilot
      People talk without thinking all of the time.
      If you doubt it, think about this: When you're talking, do you
      construct each sentence first in your mind, piecing the words
      together? Or do you simply talk, the words tumbling out in proper
      sequence and syntax?
      For the most part, it's probably the latter. You don't think about
      each word before you speak it. "Your brain," says Koch, "takes care of
      that quite well without any conscious effort on your part."
      Speaking is, in profound ways, a "nonconscious" behavior. It is a
      mental operation not directly associated with conscious feelings,
      sensations or memories. It just sort of happens, seemingly, on its own.
      The same is true about much of life. Surprisingly big chunks of it,
      Koch writes in his new book, "The Quest for Consciousness," happen
      without us being consciously aware they are happening.
      "We all do things every day, virtually every minute, that do not
      involve conscious thought, from tying our shoes, to driving to work or
      working out, to cooking dinner," said Koch. "These actions are
      essentially routine, automatic. You do them without thinking and often
      have no direct memory of them afterward."
      Neurobiologists call these actions "zombie behaviors," activities that
      occur without conscious input or self-examination. They have been a
      subject of scholarly debate for more than a century, serious grist for
      philosophers and psychologists like Friedrich Nietzsche and Sigmund
      Freud. Increasingly, they are also the stuff of science.
      Koch says neuroscience has accumulated credible evidence that the
      brain is filled with specialized sensory-motor processes, what he
      calls "zombie agents," that carry out these unthinking behaviors. He
      says there is a plausible explanation for their existence: They allow
      us to be us.
      All zombie behaviors have at least a couple of things in common: They
      happen fast. And they are, in some way, routine. Many of these
      behaviors are akin to reflexes, such as blinking when your view is
      suddenly obstructed, sneezing when something tickles your nose or
      flinching at an unexpected noise.Other zombie behaviors are more
      subtle, such as the constant stream of mental directions that keep
      your body upright, balanced and mobile when walking, that allow you to
      change your gait or step when weaving through a crowd.
      These behaviors cannot easily be done if you consciously think about
      them. It takes too much time, time that could be vital to survival or
      put to better use. And so our brains, constantly awash in sensory
      information, have evolved streamlined, one-way information pathways to
      get necessary signals from the brain to the body almost
      instantaneously, without the delaying clutter of conscious thought.
      "One of the cardinal advantages of zombie agents is that their
      specialized nature allows them to respond more rapidly than the
      general purpose perceptual system," writes Koch. "You grab for that
      pencil before you actually see it roll off the table, or you move your
      hand away from the hot burner before you feel its heat."
      This last point is important, Koch says, because it refutes the idea
      that you jerk your hand away because you consciously feel pain. You
      don't. The movement is a spinal reflex. It does not require the brain
      For humans, the presence and activity of myriad zombie agents means
      significant regions of the brain can be put to better use.
      Specifically, the cortical regions involved in higher cognitive skills
      – learning, memory, vision, language – are free to grapple with new
      problems and situations, to plan ahead. Other animals – mice and
      monkeys, for example – have been shown to possess some aspects of
      these properties, but to a lesser degree. Humans have more cortex,
      language, insight and a deeper, more reflective self-awareness.
      "It's a reasonable idea," said Larry Squire, a neuroscientist at UCSD
      and the San Diego VA Medical Center. "Animals have evolved lots of
      very specific adaptations for survival. Honeybees, for example, do
      this very elaborate dance to communicate where to find food. But they
      can use this information in only two ways: They do the dance for
      others, or they go find the food themselves. They can't do anything
      else with it.
      "Humans are different. We can apply specific information to many other
      unrelated events or actions. We're flexible. This is consciousness."
      By better understanding the biological basis of zombie behaviors,
      researchers hope they will learn more about consciousness. But it is a
      daunting task, if only because it's exceedingly difficult to always
      differentiate between the two.
      Some zombie behaviors, for example, can appear quite complex. When a
      dog wags its tail or a baby smiles, both may be doing so
      automatically, without conscious thought.
      More confoundingly, consciousness readily intrudes into zombie
      behaviors. Consider the act of tying your shoes. It's a mechanistic,
      routine action that generally requires no active thought. But at any
      moment while tying your shoes, you can suddenly become aware that,
      well, you're tying your shoes.
      Such moments happen constantly, throughout the waking day. Your brain
      is working on cruise control. Suddenly, you realize your brain is
      working on cruise control.
      "In the intact brain, zombie behaviors are so tightly interwoven with
      conscious ones that it is difficult to isolate them," says Koch. "Even
      if the response was generated automatically, awareness may follow
      within the blink of an eye."
      For scientists, parsing the distinctions between nonconsciousness and
      consciousness means studying humans. Current animals models are of
      limited value because consciousness is a subjective experience. Only
      humans can directly communicate what's going on in their minds.
      Figuring out what a lab rat is feeling is difficult, though not
      Some of the most productive research into zombie behaviors involves
      studying people who suffer from specific, clinical diseases affecting
      sensory input.
      Visual agnosia, for example, is a relatively uncommon condition in
      which a patient cannot identify an object visually, but knows
      immediately what it is if they touch it or hear it (as when a set of
      keys is jingled). The cause is believed to be linked to localized
      brain damage affecting a specific perceptual ability.
      Koch cites a particular case study that he says helps illustrate the
      presence and function of zombie agents operating beyond the kin of
      visual consciousness.
      D.F. is a 34-year-old woman who suffered widespread and irreversible
      brain damage from an episode of carbon monoxide poisoning. She
      survived but could no longer recognize most objects by sight. She was
      not blind. She could see colors, step easily over objects, catch a
      tossed ball and sketch things from memory.
      "But she can't tell whether a pencil held in front of her is
      horizontal or vertical, whether she is looking at a square or a
      triangle, and she is unable to copy simple drawings," writes Koch.
      Though she can't see things in any meaningful way, D.F. can interact
      with them with remarkable accuracy. In one experiment, she was asked
      to insert a card into a slanted slot. She did so easily, her hand and
      arm rotating automatically to orient the card to the slot. Even with
      the lights turned out halfway through the action, she had no trouble
      posting the card.
      Yet D.F. couldn't see the orientation of the slot, couldn't talk about
      it, couldn't consciously rotate her hand to match the slot's slant.
      Clearly, her abilities were being governed by brain processes outside
      conscious, visually based thought.
      Such experiments, repeated in varying degrees with patients suffering
      from blindsight (an unusual condition in which a patient with cortical
      blindness may perceive peripheral movement without actually being able
      to see anything there), epilepsy and sleep walking, all suggest that
      the brain may be operating two physically distinct and separate
      systems, like a parallel processor.
      That is, neural activity in some parts of the brain governs zombie
      behaviors while other brain regions handle sensory input that demands
      conscious thought.
      Or, posits Koch, a single network in the brain may be functioning in
      two distinct, simultaneous modes. Sensory data move through cortical
      processing stages until they trigger a stereotyped, nonconscious
      behavior. If the data are too ephemeral or weak, that's where they stop.
      But if the data are stronger or more sustained, they linger and
      resonate. Consciousness kicks in as feedback between neurons escalates.
      At the moment, these remain only ideas of what is happening in the
      brain. Technologies like functional magnetic resonance imaging, which
      allow scientists to see what parts of a brain are working in real
      time, may provide the tools to delve deeper and better, but Koch
      concedes there's a long way to go.
      We can think about consciousness, but we can't explain it.
      If zombie agents competently handle most of life's demands, a larger
      question looms: Why be conscious at all? What's the benefit?
      The answer is decidedly incomplete, and largely speculative.
      Consciousness is clearly a property of certain kinds of highly evolved
      biological organs, but not all. Your intestinal walls, for example,
      are lined by more than 100 million neurons, but Koch notes that you
      don't have conscious access to its workings.
      Consciousness presumably provides an organism with an edge over an
      organism that is not conscious. That advantage, suggests Koch, is the
      ability to take large amounts of information, rapidly boil it down to
      essential facts and then do something with the knowledge. A snarling
      lion prompts a deer to run away; the same thing may inspire a human to
      go make a spear.
      Consciousness performs a sort of executive summary function, said Koch.
      "A single, compact representation of what is out there is presented,
      for a sufficient time, to the parts of the brain that can choose among
      different plans of action. This is what conscious perception is about."
      Awareness occurs, Koch said, at the interface between sensory
      processing and mental planning.
      It's a slippery concept, hard to grasp. But then, that's the nature of
      the zombie within. Actions like learning how to dance, ride a bike or
      climb a mountain can all become zombie behaviors through repetition.
      Once mastered, it's harder to play the piano while thinking about
      specific keystrokes than it is to simply let the fingers tinkle.
      But such a talent begins with conscious thought.

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