In vivo veritas? (was: Re: Electric Field Effects in the Brain?)
usenet at out-of-phase.de
Sat Apr 19 19:45:55 EST 2003
KP-PC <k.p.collins at worldnet.att.net%remove%> wrote:
from a previous post in the same sub-thread:
> Most of why the position I'm discussing in this thread is 'difficult'
> for folks who work in Neuroscience labs derives in the fact that they
> work in artificially-spearated preparations - cultured neurons,
> slices, etc.
Aren't you forgetting the many labs working in awake and behaving
animals? I am quite sure, that those working in vivo would not agree
with you theories any more than those working in vitro or in situ.
> We disagree, here, because it's verifiable the functioning of any
> 'element' [ion, molecule, neuron. nucleus, etc.] occurs as a function
> of everything else within the global system [of course, in a
> spatially-distributed-activation-dependent way].
I am well aware of the fact that a hydrogen molecule on Mars is
theoretically influenced by one on earth - over coloumb forces - but you
will agree, that the influence is neglectable. Considering the small
amplitudes of field potentials measured only a few tens of microns
distance from the firing cell which induces them, you might agree that
electric fields may also be neglected once a certain distance from the
active cell is reached - of course we can argue how large this distance
> Isolated preparations are worthwhile, but their use does tend to lead
> to observations that are inherently artificial, incomplete, and,
> therefore, misleading.
You are aware of the fact, that many phenomena which were first
discovered in slice preparations or even cell culture have been
reproduced in vivo? Even though they are inherently artifical and
The most important aspect here is the number of relevant variables
compared to the number of total variables. One always cuts corners in
vitro - that goes without questioning. But considering the question an
experiment is hoped to answer, as long as the relevant variables are
controlled or known an in vitro experiment will lead to answers which
are relevant and fully transferable to a functioning, complete system.
p.s. your post would be much easier to read, if you would rely on
fullquotes the whole time.
More information about the Neur-sci