// This function is used to calculate the AMPA coductance values
// such that a single pulse stimulus gives rise to a 5mV local depolarization
// at every synapse location along the cell (each synapse has both an AMPA and an NMDA mechanism).
// AMPA values for each location tested, along the sections tested are saved in the tune_epsp_list
// written by Terrence Brannon, last modified by Yiota Poirazi, July 2001, poirazi@LNC.usc.edu
strdef fast_file
strdef sec_str, recstr, tuning_code
objref epsp_glu, epsp_nmda, vmvec, epsp_ic, tmpvec, ns, nc_glu, nc_nmda
proc tune_epsp_fastSOMA () {
// printf("proc tune_epsp_fast (%s.v(%g))\n", secname(), $2)
R = $2 // synapse location
epsp_glu = new GLU(R)
epsp_nmda = new NMDA(R) //before was NMDAb (I don't Know why, jose)
tuned = 0 // initial values before tuning
old_GMAX = 0
ns = new NetStim(0.5)
ns.start = 20
ns.number =1
while (!tuned) {
nc_glu = new NetCon(ns,epsp_glu)
nc_glu.delay=0
nc_nmda = new NetCon(ns,epsp_nmda) //before was epsp_glu, I don't know why,jose
nc_nmda.delay=0
nc_glu.weight = GMAX // previously calculated maximum AMPA conductance
nc_nmda.weight = GMAX*NMDA_AMPA_RATIO // maximum NMDA conductance
tmpvec = new Vector()
sprint(recstr, "tmpvec.record(&soma[0].v(0.5))") // record depolarization at synapse
execute1(recstr)
init()
run()
vmvec = tmpvec.c
// test if resulting depolarization is closed to the desired value (5mV)
if (epsilon_equal(vmvec.max(),desired_voltageSOMA,$3)) {
tuned = 1 // if yes, stop
printf("\t\tTUNED.\n")
} else { // if no, update the GMAX value and test again
diffa = desired_voltageSOMA-BASELINE
diffb = vmvec.max()-BASELINE
ratio = diffa/diffb
// if (diffa>diffb){
// GMAX = GMAX*1.1 //GMAX*ratio
// }else{
// GMAX = GMAX*0.9
// }
GMAX=GMAX+(vmvec.max()-desired_voltageSOMA)/vmvec.max()*GMAX
print "\t\tnew GMAX: ", GMAX
}
}
sprint(tuning_code,"%s tune_epsp_list.append(new EPSPTuning(\"%s\",%f,%f,1))", secname(), secname(), x, GMAX)
$o4.printf("%s\n", tuning_code)
}
// test if difference between desired and actual voltage is smaller than epsilon
func epsilon_equal() {
printf("epsilon_equal(%f,%f,%f)\n", $1,$2,$3)
diff = ($1-$2)
if (abs(diff) < $3) {
return(1)
} else {
return(0)
}
}