modeling Electrical Coupling

[davidfourie]

I am using the "gap junction" specification from the neuron book to link two neurons (soma and soma1).

Code: Select all

objref g[2]
  soma g[0] = new Gap()
  soma1 g[1] = new Gap()

soma g[0].loc(0.5)     // middle of soma 
soma1 g[1].loc(0.5)   // middle of soma1

  g[0].r = 3
  g[1].r = 3
  
  
setpointer g[0].vgap, soma1.v(0.5)
setpointer g[1].vgap, soma.v(0.5)

is there any way of adding a delay to this?

[ted]

NMODL does have a DELAY keyword (see https://www.neuron.yale.edu/phpBB2/viewtopic.php?t=193)

[davidfourie]

The link doesn't give any details of the use of the keyword.

would I declare it in the .mod file of the Gap junction.

Code: Select all

COMMENT
  Electrical coupling modelled with a gap junction between the pre and post neruons.
  
  Model is based on Gap Junction in (Carnevale and Hines 2006a)

ENDCOMMENT


NEURON {
  POINT_PROCESS elecSyn
  POINTER vgap
  RANGE r, i
  NONSPECIFIC_CURRENT i
}

PARAMETER { r = 1e10 (megohm) }

ASSIGNED {
  v (millivolt)
  vgap (millivolt)
  i (nanoamp)
}

BREAKPOINT { i = (v - vgap)/r }

I have tried to model this gap junction using a NET_RECEIVE block without much success.
I would prefer to use the standard Gap code with a slight delay.

Dave

[hines]

The use of explicit DELAY may not be
well founded in a gap junction context.
If you want more delay in the effect
of a soma voltage in one cell due to
a voltage change in another cell via
gap junction coupling, a physically
meaningful way is to add some cable
properties between the soma and the
gap junction.