Role for short term plasticity and OLM cells in containing spread of excitation (Hummos et al 2014)

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Accession:168314
This hippocampus model was developed by matching experimental data, including neuronal behavior, synaptic current dynamics, network spatial connectivity patterns, and short-term synaptic plasticity. Furthermore, it was constrained to perform pattern completion and separation under the effects of acetylcholine. The model was then used to investigate the role of short-term synaptic depression at the recurrent synapses in CA3, and inhibition by basket cell (BC) interneurons and oriens lacunosum-moleculare (OLM) interneurons in containing the unstable spread of excitatory activity in the network.
References:
1 . Hummos A, Franklin CC, Nair SS (2014) Intrinsic mechanisms stabilize encoding and retrieval circuits differentially in a hippocampal network model. Hippocampus 24:1430-48 [PubMed]
2 . Hummos A, Nair SS (2017) An integrative model of the intrinsic hippocampal theta rhythm. PLoS One 12:e0182648 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s): Dentate gyrus granule GLU cell; Hippocampus CA3 pyramidal GLU cell; Hippocampus CA3 interneuron basket GABA cell; Hippocampus CA3 stratum oriens lacunosum-moleculare interneuron; Abstract Izhikevich neuron;
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s): Acetylcholine; Gaba; Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Activity Patterns; Epilepsy; Storage/recall;
Implementer(s):
Search NeuronDB for information about:  Dentate gyrus granule GLU cell; Hippocampus CA3 pyramidal GLU cell; Hippocampus CA3 interneuron basket GABA cell; Acetylcholine; Gaba; Glutamate;
NEURON {
  POINT_PROCESS IZH
  NONSPECIFIC_CURRENT vv
  RANGE a,b,c,d,e,f,I,vv,thresh, vr, vt, vpeak, aACH, cACH, dACH,alphaShutdown, bACH, ACHshutdown, aMin, aMax, g, vrACH, k, Cap, uinit
}
UNITS {
	(mV) = (millivolt)
    (nA) = (nanoamp)
	(pA) = (picoamp)
	(uS) = (microsiemens)
	(nS) = (nanosiemens)
}

INITIAL {
u = uinit
net_send(0,1)
}

PARAMETER {  
: these are default parameters, if parameters were not set up by the user. 
  k = 0.0011 (nA/mV2) :(1/mV*megaohm) 
  a = 0.01 (1/ms)
  b = 0.0002 (uS)
  c = -65 (mV)
  d = .001 (nA)

 
  vpeak= 30 (mV)
  vv = 0 (mV)
  vr = - 70 (mV)
  vt = - 45 (mV)

  a_OLM = 0.002
  ACH = 1 	 		: Baseline levels of ACh
  dACH = 0 (nA)		: Determines the direction of the magnitude of ACh effects on the Izhikevitch parameter 'd' 
  cACH = 0 (mV)		: Determines the direction of the magnitude of ACh effects on the Izhikevitch parameter 'c' 
  vrACH = 0 (mV)	: Determines the direction of the magnitude of ACh effects on Cell's resting membrane potential  
  bACH = 1.25
  
  ACHshutdown = 0	: Takes the value of 1 only for OLM cells to allow the calculation of parameter 'a' 
  
  uinit = 0 (nA)
  
}

STATE { u }

ASSIGNED {
  }

BREAKPOINT {
  SOLVE states METHOD derivimplicit
  vv = -(k*(v - (vr + vrACH * (-1+ ACH) ))*(v - vt) - u)
  
  a_OLM = 0.023*ACH^2 - 0.022*ACH + 0.002 : The parameter 'a' for OLM cells was fit to the polynomial function of ACh of second degree to reproduce the effects described in the paper 
}

DERIVATIVE states {
    u' = (a_OLM * ACHshutdown + a )*(b*(v - (vr + vrACH * (-1+ ACH) ))-u)
}

NET_RECEIVE (w) {
  if (flag == 1) {
    WATCH (v>vpeak) 2
  } else if (flag == 2) {
    net_event(t)
    v = c + cACH * (-1+ACH) 
    u = u+d + dACH * (1-ACH)
  }
}



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