// Playing Recordings of EPSCs into the model cell
// 1. This .hoc code plays in a whole-cell patch clamp recording of an SPN into the model.
// 2. The recorded cell was voltage-clamped at -53mV (~resting membrane potential), and so these currents are synaptic inputs.
// 3. The vector of synaptic inputs was recorded at 1kHz, and is the file "EPSCs_Filtered.txt"
// 4. For varying values of the parameter GKABAR, the membrane potential trace in response to this input is recorded into a .dat file
// 5. From this .dat file, the firing frequency and other properites can be determined
// 6. In the current file, GKABAR is varied between 20-18mS/cm2 in 0.1mS/cm2 increments
// Created: March 2013, Linford Briant
load_file("Cell.hoc")
proc init() {
finitialize(-55)
/*
if (cvode.active()) {
cvode.re_init()
} else {fcurrent()
}
frecord_init()
*/
}
// This ensures that as the parameter GKABAR is varied, the cell has a resting membrane potential of -55mV
objectvar ClampVector, ClampFile
ClampVector=new Vector()
ClampFile=new File()
ClampFile.ropen("ClampFiddyFive_withNa.dat")
ClampVector.scanf(ClampFile)
steps_per_ms=1
dt=1
tstop=50e3
objectvar stim
stim=new IClamp(0.5)
stim.dur=tstop
stim.del=0
// stim.amp=ClampVector.x[0]
// This means we are not setting the RMP of every cell to -55mV
stim.amp=0
access SPNcells[0].soma
SPNcells[0].soma.gkabar_borgka=0.02
// Playing in synaptic train (08-09-23a.smr) "EPSCs_Filtered.txt"
// This has been filtered to remove noise
// This has been down-sampled to 1kHz
// This has been processed in MATLAB so that the trace is in nA (units used in NEURON), as the output in Spike2 is in pA.
objectvar EPSC_vec, EPSC_File
EPSC_vec=new Vector()
EPSC_File=new File()
EPSC_File.ropen("EPSCs_Filtered.txt")
EPSC_vec.scanf(EPSC_File)
objectvar EPSC_stim
EPSC_stim = new IClamp(0.5)
EPSC_stim.dur=1e9
EPSC_stim.del=0
EPSC_vec.play(&EPSC_stim.amp,1)
nstart=0
nvrec=20 // one recording vector for each value of gkabar_borgka between 0.005-0.001 in increments of 0.00005
nstimrec=nvrec-nstart // one stim vector for each value of gkabar_borgka
SPNcells[0].soma.gkabar_borgka=0.02-(0.0001*nstart)
// stim.amp=ClampVector.x[nstart]
objectvar vrec[nvrec-nstart], stimrec[nvrec-nstart]
for i=0, nvrec-nstart-1 vrec[i]=new Vector()
for i=0, nvrec-nstart-1 stimrec[i]=new Vector()
vrec[0].record(&SPNcells[0].soma.v)
stimrec[0].record(&stim.i)
run()
print stim.amp, gkabar_borgka
objectvar DataM, M, DataK, K
M=new Matrix(vrec[0].size(),nvrec-nstart+1) // One extra column for time.
K=new Matrix(stimrec[0].size(),nvrec-nstart+1) // One extra column for time.
M.setcol(1,vrec[0])
K.setcol(1,stimrec[0])
// Set first column in matrices M and N to time.
objectvar vdt
vdt = new Vector()
vdt.resize(vrec[0].size())
vdt.indgen(dt)
M.setcol(0,vdt)
K.setcol(0,vdt)
for j=nstart+1,nvrec-1 {
print j
vrec[j-nstart].record(&SPNcells[0].soma.v)
stimrec[j-nstart].record(&stim.i)
gkabar_borgka=0.02-(0.0001*j)
// stim.amp=ClampVector.x[j]
print stim.amp, gkabar_borgka
run()
M.setcol(j+1-nstart,vrec[j-nstart])
K.setcol(j+1-nstart,stimrec[j-nstart])
}
// Save matrix of recorded vectors to .dat dataset.
DataM=new File()
DataK=new File()
DataM.wopen("SpontaneousFiringFrequency_GKABAR_1_V.dat")
M.fprint(DataM, " %g")
DataM.close("SpontaneousFiringFrequency_GKABAR_1_V.dat")
DataK.wopen("SpontaneousFiringFrequency_GKABAR_1_current.dat")
K.fprint(DataK, " %g")
DataK.close("SpontaneousFiringFrequency_GKABAR_1_current.dat")