begintemplate Cell public soma, syn create soma objref syn proc init() { create soma soma { diam = 20 L = 20 insert hh syn = new ExpSyn(.5) } } endtemplate CellEnclosing a general cell specification within a Template or class allows one to create many instances of the cell. It is up to the simulation creator to determine a convenient policy for parameterizing the cell. E.g. create the cell and then modify parameters, or parameterize the template and specify them as arguments when a cell instance is created. One important organizing principle will often be the 3-d position of the cell.
Recall from exercise 12 that the ExpSyn "synapse" can have any number of inputs with different weights. So it is convenient with this single segment model to create a single synapse when the cell is created. Note that two cells can be connected only if there is a target point process on the post synaptic cell which defines what happens (eg time course of conductance change) when an event arrives through the connection. If cells have complex morphology, then it may make sense to create a synapse only when a connection is made to a location that does not have one.
// create two cells objref cell[2] for i=0,1 cell[i] = new Cell() access cell[0].somaAt this point we have two cells each with an ExpSyn synapse but they do not interact.
// connect the cells together objref ncl = new List() proc netcon() { // $o1 = source cell $o2 = target cell $o1.soma ncl.append(new NetCon(&v(.5), $o2.syn, -10, .001, 3)) } netcon(cell[0], cell[1)) netcon(cell[1], cell[2])With this policy, our authoritative list of connections is the ncl list.
// show the connections xpanel("NetCon Info") for i=0, nclist.count-1 { tobj = nclist.object(i) sprint(tstr, "%s -> %s -> %s", tobj.precell, tobj, tobj.postcell) xlabel(tstr) xpvalue("weight", &tobj.weight, 1) xpvalue("delay", &tobj.delay, 1) } xpanel()It's one thing to manage two connections, quite another to manage thousands. Some help in this task is provided by functions that return various kinds of NetCon lists, e. g. all the NetCons that connect to the same postcell, post synaptic point process, precell, etc. However, at this time there are no generic gui tools to view or manage networks and it is necessary to craft viewing, control, and management routines based on the details of the particular network being investigated.
Reduce one of the weights and then the other to 0.002 . Since the cells are identical, why are the results different?