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Nicolette Sinensky

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How does virtuality translate into reality?

This week in my bioelectricity class, we spoke about electrical stimulation of nerves. One method of stimulation is to place a electrode directly on the surface of a nerve. One of the considerations of this method, however, is that the anode (positively charged side) and cathode (negatively charged side) of the electrode each cause a redistribution of charge around the electrode. Consequently, the anode induces a complementary "virtual cathode" and the cathode creates a complementary "virtual anode." These components aren't actually there, but we can observe a similar redistribution of charge that implies that something unseen is going on. Despite the fact that these components are not physically present, they have real effects on the functionality of both the electrode and the nerve. The virtual cathode and anode can cause a very real, measurable voltage change in the nerve, and can effectively block a nerve signal, which is dependent on the voltage.

In what other ways can intangible entities have physical manifestations? In this case, the unintended effect has a negative consequence, but can we find useful applications of such a circumstance?

Also, if these imaginary aspects can effect reality, what does that say about our definition of what is real and what isn't?

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    Apr 7 2012: Maybe I do not properly understand but bear with me as I oversimplify.

    Re: anode/cathode virtual/real.

    If I run both hot and cold water taps into a basin would you say that the temperature of the collected water is virtual ?

    Also, I would not think that blocking a nerve signal is necessarily a negative in every instance. Perhaps it might be considered for study in non chemical(non-addictive or liver damaging) applications for treating epilepsy or chronic pain ??
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      Apr 9 2012: Terry,
      No, I wouldn't call the temperature virtual. But imagine I knew the amounts and temperatures of the water I was putting into the basin, and could from that information predict the total temperature of the basin. Yet when I actually measure the temperature, I get something hotter or colder than expected. I might say that there's another "virtual tap" affecting my experiment.

      In terms of your idea, you are absolutely right about blocking nerve signals to alleviate pain. I don't know if this particular virtual anode/cathode phenomenon has ever been exploited, but much research has been done on Transcutaneous Electrical Nerve Stimulation (TENS), which uses electrical stimulation to block pain. Here's an article about it:
      http://www.bbc.co.uk/health/physical_health/conditions/tens1.shtml
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        Apr 9 2012: Ah, I understand a little more now. Thank you for bearing with me.
        It seems like an enticing mystery waiting to be solved.

        It's Interesting you say "hotter or colder than would be expected". So there is sometimes a greater and sometimes a lesser "virtual charge" measured ?
        One or the other was my assumption..

        Forgive me now if this seems to take a morbid turn.
        I suppose it is hard to stop a living nerve carrying other signals while you do your tests. So are these tests you can only carry out on living subjects ?

        I have a close friend who damaged her central nervous system in an accident. It fires off every now and then resulting, sometimes in paralyses, sometimes in severe pain. Funny thing is that it's almost an auto immune problem, her central nervous system thinks its helping. I must mention TENS to her, thank you for sharing the article but I imagine that blocking signals is what she needs, not stimulation. So I wish you the best with your experiments, maybe some day something like this could be used to help people with the same problems.

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