On Fri, Aug 8, 2008 at 12:46 AM, Robin van Spaandonk < [EMAIL PROTECTED]> wrote:
> In reply to Horace Heffner's message of Thu, 7 Aug 2008 13:37:57 -0800: > Hi, > > IIRC nerve cells conduct through a process of K+ Na+ exchange. I don't > think > they are electrically very conducting, hence any such signal would likely > be > heavily damped, and result mostly in heat. The considerable processing > power of > the human brain is due primarily to vast parallel processing, rather than a > "fast" processor. > Axons are not good as antennas since currents travel only in radial direction. In antennas it travels axially. Axons are thus not vulnerable to electric dipole radiation. It is not even vulnerable to electric dipole radiation in the radial direction since the net electric dipole moment of a signal in a nerve is zero. I saw an article where the signals was termed as sound and not being electrical. This is a matter of definition of course. However there should be a net electric quadrupole moment of a traveling nerve signal. It should thus be affected by electric quadrupole radiation. The term quadrupole radiation is somewhat ambiguous. These two meanings could be assigned to it. 1. Dipole radiation from an electric quadrupole. This is usually what people mean when they talk about quadrupole radiation. It is not a wise usage of terms but currently established. 2. Quadrupole radiation without a dipole component. This radiation would have no impact on a dipole antenna. It would only affect other electrical quadrupoles. I havent seen this type but it would be easy to build one. Strictly speaking case 1 is not quadrupole radiation. Be cautious about this when reading about quadrupoles. So, anyone interested in caculating the radiation from a nerve cell? You can use this as an example www.djk.se/physics but it is only case 1 quadrupole radiation (section 3). Since radiation is time reversible, unless you add thermodynamics, the cell will be receptible to the same radiation it is transmitting. David -- David Jonsson Sweden phone callto:+46703000370
