Synaptic information transfer in computer models of neocortical columns (Neymotin et al. 2010)

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Accession:136095
"... We sought to measure how the activity of the network alters information flow from inputs to output patterns. Information handling by the network reflected the degree of internal connectivity. ... With greater connectivity strength, the recurrent network translated activity and information due to contribution of activity from intrinsic network dynamics. ... At still higher internal synaptic strength, the network corrupted the external information, producing a state where little external information came through. The association of increased information retrieved from the network with increased gamma power supports the notion of gamma oscillations playing a role in information processing."
Reference:
1 . Neymotin SA, Jacobs KM, Fenton AA, Lytton WW (2011) Synaptic information transfer in computer models of neocortical columns. J Comput Neurosci. 30(1):69-84 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism: Neocortex;
Cell Type(s): Neocortex V1 pyramidal corticothalamic L6 cell; Neocortex V1 pyramidal intratelencephalic L2-5 cell; Neocortex V1 interneuron basket PV cell; Neocortex fast spiking (FS) interneuron; Neocortex spiny stellate cell; Neocortex spiking regular (RS) neuron; Neocortex spiking low threshold (LTS) neuron;
Channel(s): I Na,t; I A; I K;
Gap Junctions:
Receptor(s): GabaA; AMPA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Activity Patterns; Information transfer;
Implementer(s): Lytton, William [billl at neurosim.downstate.edu]; Neymotin, Sam [samn at neurosim.downstate.edu];
Search NeuronDB for information about:  Neocortex V1 pyramidal corticothalamic L6 cell; Neocortex V1 pyramidal intratelencephalic L2-5 cell; Neocortex V1 interneuron basket PV cell; GabaA; AMPA; NMDA; I Na,t; I A; I K;
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ncdemo
readme.txt
A.mod
AMPA.mod *
AMPAr.mod
clampex.mod *
cp.mod *
cp2.mod *
field.mod
GABAa.mod
GABAar.mod
GABAb.mod
GABAbr.mod
H.mod
Iahp.mod *
Ican.mod *
IL.mod
IL3.mod *
infot.mod *
intf_.mod
intfsw.mod *
kdr2.mod *
kmbg.mod
misc.mod *
naf2.mod *
nap.mod *
NMDA.mod *
NMDAr.mod
nthh.mod *
ntIh.mod *
ntt.mod *
OFThpo.mod
OFThresh.mod
pregencv.mod
stats.mod
updown.mod *
vecst.mod
bg_cvode.inc
misc.h *
mosinit.hoc
netcon.inc *
netrand.inc
ofc.inc
                            
: $Id: netcon.inc,v 1.16 2010/03/28 16:19:27 billl Exp $

COMMENT
USAGE: for most receptors
 *****************************************************************************
    NEURON {
      POINT_PROCESS NAME
    }

    PARAMETER {
      Cdur	= 1.08	(ms)		: transmitter duration (rising phase)
      Alpha	= 1	(/ms mM)	: forward (binding) rate
      Beta	= 0.02	(/ms)		: backward (unbinding) rate
      Erev	= -80	(mV)		: reversal potential
    }
    
    INCLUDE "netcon.inc"
 *****************************************************************************

USAGE: for NMDA receptor
 *****************************************************************************
    NEURON{ POINT_PROCESS NMDA
      RANGE B 
    }

    PARAMETER {
      mg        = 1.    (mM)     : external magnesium concentration
      Cdur	= 1.	(ms)	 : transmitter duration (rising phase)
      Alpha	= 4.	(/ms mM) : forward (binding) rate
      Beta	= 0.0067 (/ms)	 : backward (unbinding) rate 1/150
      Erev	= 0.	(mV)	 : reversal potential
    }

    ASSIGNED { B }

    INCLUDE "netcon.inc"
    : EXTRA BREAKPOINT MUST BE BELOW THE INCLUDE
    BREAKPOINT {
      rates(v)
      g = g * B : but don't really need to readjust conductance
      i = i * B : i = g*(v - Erev)
    }

    PROCEDURE rates(v(mV)) {
      TABLE B
      DEPEND mg
      FROM -100 TO 80 WITH 180
      B = 1 / (1 + Exp1(0.062 (/mV) * -v) * (mg / 3.57 (mM)))
    }
 *****************************************************************************
ENDCOMMENT

INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
  RANGE g, Erev, fflag
  RANGE sid,cid
  NONSPECIFIC_CURRENT i
  GLOBAL Cdur, Alpha, Beta, Rinf, Rtau
}

UNITS {
  (nA) = (nanoamp)
  (mV) = (millivolt)
  (umho) = (micromho)
  (mM) = (milli/liter)
}

PARAMETER {
  fflag = 0
  sid = -1 (1) : synapse id, from cell template
  cid = -1 (1) : id of cell to which this synapse is attached
}

ASSIGNED {
  v		(mV)		: postsynaptic voltage
  i 		(nA)		: current = g*(v - Erev)
  g 		(umho)		: conductance
  Rinf				: steady state channels open
  Rtau		(ms)		: time constant of channel binding
  synon
}

STATE {Ron Roff}

INITIAL {
  PROTECT Rinf = Alpha / (Alpha + Beta)
  PROTECT Rtau = 1 / (Alpha + Beta)
  synon = 0
}

BREAKPOINT {
  SOLVE release METHOD cnexp
  g = (Ron + Roff)*1(umho)
  i = g*(v - Erev)
}

DERIVATIVE release {
  Ron' = (synon*Rinf - Ron)/Rtau
  Roff' = -Beta*Roff
}

: following supports both saturation from single input and
: summation from multiple inputs
: if spike occurs during CDur then new off time is t + CDur
: ie. transmitter concatenates but does not summate
: Note: automatic initialization of all reference args to 0 except first

NET_RECEIVE (weight, on, nspike, r0, t0 (ms)) {
  : flag is an implicit argument of NET_RECEIVE and  normally 0
  if (t>0) { : bug fix so that init doesn't send a false event
    if (flag == 0) { : a spike, so turn on if not already in a Cdur pulse
      nspike = nspike + 1
      if (!on) {
        r0 = r0*Exp1(-Beta*(t - t0))
        t0 = t
        on = 1
        synon = synon + weight
        Ron = Ron + r0
        Roff = Roff - r0
      }
      : come again in Cdur with flag = current value of nspike
      net_send(Cdur, nspike)
    }
    if (flag == nspike) { : if this associated with last spike then turn off
      r0 = weight*Rinf + (r0 - weight*Rinf)*Exp1(-(t - t0)/Rtau)
      t0 = t
      synon = synon - weight
      Ron = Ron - r0
      Roff = Roff + r0
      on = 0
    }
  }
}

FUNCTION Exp1(x) {   
  if (x < -100) {
    Exp1  = 0
  } else if (x > 100) {
    Exp1 = exp(100)
  } else{
    Exp1 = exp(x)
  }
}

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