Persistent Spiking in ACC Neurons (Ratte et al 2018)

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Accession:255569
"Neurons use action potentials, or spikes, to encode information. Some neurons can store information for short periods (seconds to minutes) by continuing to spike after a stimulus ends, thus enabling working memory. This so-called “persistent” spiking occurs in many brain areas and has been linked to activation of canonical transient receptor potential (TRPC) channels. However, TRPC activation alone is insufficient to explain many aspects of persistent spiking such as resumption of spiking after periods of imposed quiescence. Using experiments and simulations, we show that calcium influx caused by spiking is necessary and sufficient to activate TRPC channels and that the ensuing positive feedback interaction between intracellular calcium and TRPC channel activation can account for many hitherto unexplained aspects of persistent spiking."
Reference:
1 . Ratté S, Karnup S, Prescott SA (2018) Nonlinear Relationship Between Spike-Dependent Calcium Influx and TRPC Channel Activation Enables Robust Persistent Spiking in Neurons of the Anterior Cingulate Cortex. J Neurosci 38:1788-1801 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s):
Channel(s): I CAN; I_AHP; I Na,t; I K;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: XPPAUT;
Model Concept(s): Calcium dynamics; Action Potentials; Working memory; Persistent activity;
Implementer(s): Prescott, Steven [steve.prescott at sickkids.ca]];
Search NeuronDB for information about:  I Na,t; I K; I CAN; I_AHP; 
# basic XPP code for Ratte et al. 2018 J Neurosci 14: 1788-1801 
# written by Steve Prescott, last modified July 9, 2016

##################
   
dv/dt = (Idc+Idc2(t)+Idc3(t)+I1a(t)+I1b(t)+I2a(t)+I2b(t)+I3a(t)+I3b(t)+I4a(t)+I4b(t)+I5a(t)+I5b(t)+I6a(t)+I6b(t)-gna*minf(V)*(V-Vna)-gk*w*(V-VK)-gl*(V-Vl)-gcan*p2*(v-Vcan)-gahp*q*(v-Vk)-gahp2*q2*(v-Vk)-gahp3*q3*(v-Vk)-gca*p*switch*(v-vca))/c
dw/dt = phi*(winf(V)-w)/tauw(V)



q' = (q_inf-q)/tau_q
q2' = (q2_inf-q2)/tau_q2
q3' = (q3_inf-q3)/tau_q3


# for new AD current
param gcan=2
param Vcan=0
p2inf =1/(1+exp((cai-caihalf)/caislope))
param caihalf=.0004
# Cai in microM range
param caislope=-0.0002
p2' = (p2inf-p2)/tau_p2
param tau_p2=1
# essentially instantaneous with change in Cai


# for ca influx and decay
dcai/dt = (-SAvol*(gca*p*(V-Vca)))/F-(cai-0)/tau_ca
#dcai/dt = ((-SAvol*(gca*p*(V-Vca)))/F-(cai-0))/tau_ca - original in correct
p' = (p_inf-p)/tau_p
p_inf = 1/(1+exp((v-vhalfp)/vslopep))
param gca=0.005
# gca also gets 10^-3 shift
param switch=1
param vhalfp=0
param vslopep=-5
param tau_p=1
p(0)=0
cai(0)=0
vca=100
param F=96485
param tau_ca=2000
# lengthened so that CAN persists during prolonged hyperpol steps

# FOR SPHERICAL SOMA
param shape=3
# shape=3 for sphere, shape=2 for cylinder
!SAvol=shape/(10*r)
param r=0.01
# 10 micron radius soma
# p2

# for AHP current
q_inf = 1/(1+exp((v-vhalfq)/vslopeq))
param gahp=0
param vhalfq=0
param vslopeq=-5
param tau_q=25
q(0)=0

q2_inf = 1/(1+exp((v-vhalfq2)/vslopeq2))
param gahp2=50
param vhalfq2=0
param vslopeq2=-5
param tau_q2=200
q2(0)=0

q3_inf = 1/(1+exp((v-vhalfq3)/vslopeq3))
param gahp3=25
param vhalfq3=0
param vslopeq3=-5
param tau_q3=2000
q3(0)=0
#all three gahps are the same except for tau, and adjustments to their density

V(0)=-70
w(0)=0.000025
minf(v)=.5*(1+tanh((v-v1)/v2))
winf(v)=.5*(1+tanh((v-v3)/v4))
tauw(v)=1/cosh((v-v3)/(2*v4))
param vk=-90,vl=-70,vna=50
param gk=20,gl=2,gna=20
param v1=-1.2,v2=18
param v3=0,v4=10
param phi=.15,c=2

# STIMULATION
param idc=0
# use these to trigger spikes... t_run is short to that 1 spike is triggered per pulse
I1a(t)=sign(t>t_start1)*I_stim_a
I1b(t)=sign(t>(t_start1+t_run))*(-1*I_stim_a)
I2a(t)=sign(t>t_start2)*I_stim_a
I2b(t)=sign(t>(t_start2+t_run))*(-1*I_stim_a)
I3a(t)=sign(t>t_start3)*I_stim_a
I3b(t)=sign(t>(t_start3+t_run))*(-1*I_stim_a)
I4a(t)=sign(t>t_start4)*I_stim_a
I4b(t)=sign(t>(t_start4+t_run))*(-1*I_stim_a)
I5a(t)=sign(t>t_start5)*I_stim_a
I5b(t)=sign(t>(t_start5+t_run))*(-1*I_stim_a)
I6a(t)=sign(t>t_start6)*I_stim_a
I6b(t)=sign(t>(t_start6+t_run))*(-1*I_stim_a)
# use this to introduce sustained depol or hyperpol
Idc2(t)=sign(t>t_startDC2)*Idc2_
Idc3(t)=sign(t>t_startDC3)*Idc3_

param I_stim_a=90,t_start1=1100,t_start2=1200,t_start3=1300,t_start4=1400,t_start5=1500,t_start6=1600,t_run=5
param Idc2_=0,t_startDC2=4000,Idc3_=0,t_startDC3=6000

@ total=100000,dt=.1,xlo=-100,xhi=60,ylo=-.125,yhi=.6,xp=v,yp=w
@ meth=runge-kutta
@ MAXSTOR=10000000

done

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