This directory contains 2 files out of a bigger simulation which reproduced
a model from the paper:
  Holmes WR & Levy WB: Insights into associative
  long-term potentiation from computational models of NMDA
  receptor-mediated caclcium influx and intracellular calcium
  concentrations changes.  J. Neurophysiol. 63, 1148-1168, 1990.

granule_comps sets up the prototypes and should be included.  
spine.p contains the description of one spine attached to a small piece of
  dendrite, which is connected to a (fake) soma.

These files were included primarily in the examples to show how to use the
concen library objects, how to setup the DIFFUSE message for the read_cell
routine, and how to use the *compt feature of the read_cell routine.  

There are some problems with this model.  The manuelconduct implementation
of the synaptic conductances is very stiff and I discourage people from 
using it.  It will work as in the original Holmes Levy model if for every
time the synapses fire the field z is changed as follows: for NMDA 
z=z+0.00110, for non_NMDA z=z+0.00505.  Another problem was a typo in the
original paper, which was reproduced as an error in the difpool object code.
For the shape of these spines however this error had no numerical
consequences.  This error has been corrected in genesis 1.3  and results
for this model are identical.  Finally, the difpool objects handles one-
dimensional diffusion along the axis for which Len is set.  Diffusion from
the spine into the dendrite itself is however a two-dimensional problem
which is not handled correctly by the difpool object.  This does not
change the results much because the actual concentration changes at the
base of the spine are very small.

These files were written to be run from neurokit.  Make a userprefs file
which calls the "make_cylind_compartment" routine and makes a /library.
Call from within the library "make_the_spine_prototype" routine.  Then you
can open the spine.p file.

Erik De Schutter, Woods Hole August 1991
