Look at displacement current:
http://en.wikipedia.org/wiki/Displacement_current
particularly, note that there are two parts: one resulting from the change
of the electric field, and another from polarization.
cwenhoo wrote:
>>From Luck's book, p.32:
>> "When a dipole is present in a conductive medium such as the brain,
> current is conducted throughout that medium until it reaches the
> surface...Electricity does not just run directly between two poles of
> a dipole in a conductive medium, but instead spreads out through the
> conductor."
>> "Another important point is that electricity travels at nearly the
> speed of light. For all practical purposes, the voltages recorded at
> the scalp reflect what is happening in the brain at the same moment in
> time."
>> My question is, what generates this current flow? I mean I can
> understand if the conductive medium is a piece of metal, then a dipole
> results in direct movement of electrons.
>> But what about the brain? What is even more confusing to me is that
> action potentials are not even near the speed of light, so how can
> this current resulting from the dipoles in the brain travel that fast?
> _______________________________________________
> Neur-sci mailing list
>Neur-sci from net.bio.net>http://www.bio.net/biomail/listinfo/neur-sci>>
