# simplified corticospinal cell model (6 compartment)
from neuron import h
from math import exp,log
Vrest = -88.5366550238
h.v_init = -75.0413649414
h.celsius = 34.0 # for in vitro opt
# geom properties
somaL = 48.4123467666
somaDiam = 28.2149102762
axonL = 594.292937602
axonDiam = 1.40966286462
apicL = 261.904636003
apicDiam = 1.5831889597
bdendL = 299.810775175
bdendDiam = 2.2799248874
# passive properties
axonCap = 1.01280903702
somaCap = 1.78829677463
apicCap = 1.03418636866
bdendCap = 1.89771901209
rall = 114.510490019
axonRM = 3945.2107187
somaRM = 18501.7540916
apicRM = 10751.193413
bdendRM = 13123.00174
# Na, K reversal potentials calculated from BenS internal/external solutions via Nernst eq.
p_ek = -104.0 # these reversal potentials for in vitro conditions
p_ena = 42.0
# h-current
h.erev_ih = -37.0 # global
gbar_h = 0.000140956438043
h_gbar_tuft = 0.00565 # mho/cm^2 (based on Harnett 2015 J Neurosci)
# d-current
gbar_kdmc = 0.000447365630734
kdmc_gbar_axonm = 20
# spiking currents
gbar_nax = 0.0345117294903
nax_gbar_axonm = 5.0
nax_gbar_somam = 1.0
nax_gbar_dendm = 1.0
gbar_kdr = 0.0131103978049
kdr_gbar_axonm = 5.0
# A few kinetic params changed vis-a-vis kdr.mod defaults:
kdr_vhalfn = 11.6427471384
gbar_kap = 0.0898600246397
kap_gbar_axonm = 5.0
# A few kinetic params changed vis-a-vis kap.mod defaults:
kap_vhalfn = 32.7885075379
kap_tq = -52.0967985869
kap_vhalfl = -59.7867409796 # global!!
# other ion channel parameters
cal_gcalbar = 4.41583533572e-06
can_gcanbar = 4.60717910591e-06
calginc = 1.0
h_lambda = 325.0
kBK_gpeak = 5.09733585163e-05
kBK_caVhminShift = 43.8900261407
cadad_depth = 0.119408607923
cadad_taur = 99.1146852282
###############################################################################
# SPI6 Cell
###############################################################################
class SPI6 ():
"Simplified Corticospinal Cell Model"
def __init__(self,x=0,y=0,z=0,ID=0):
self.x,self.y,self.z=x,y,z
self.ID=ID
self.all_sec = []
self.add_comp('soma')
self.set_morphology()
self.insert_conductances()
self.set_props()
def add_comp(self, name):
self.__dict__[name] = h.Section(name=name)#,cell=self)
self.all_sec.append(self.__dict__[name])
def set_morphology(self):
self.add_comp('axon')
self.add_comp('Bdend')
self.add_comp('Adend1')
self.add_comp('Adend2')
self.add_comp('Adend3')
self.apic = [self.Adend1, self.Adend2, self.Adend3]
self.basal = [self.Bdend]
self.alldend = [self.Adend1, self.Adend2, self.Adend3, self.Bdend]
self.set_geom()
self.axon.connect(self.soma, 0.0, 0.0)
self.Bdend.connect(self.soma, 0.5, 0.0) # soma 0.5 to Bdend 0
self.Adend1.connect(self.soma, 1.0, 0.0)
self.Adend2.connect(self.Adend1, 1.0, 0.0)
self.Adend3.connect(self.Adend2, 1.0, 0.0)
def set_geom (self):
self.axon.L = axonL; self.axon.diam = axonDiam;
self.soma.L = somaL; self.soma.diam = somaDiam
for sec in self.apic: sec.L,sec.diam = apicL,apicDiam
self.Bdend.L = bdendL; self.Bdend.diam = bdendDiam
def activeoff (self):
for sec in self.all_sec: sec.gbar_nax=sec.gbar_kdr=sec.gbar_kap=0.0
def set_axong (self):
axon = self.axon
axon.gbar_kdmc = gbar_kdmc * kdmc_gbar_axonm
axon.gbar_nax = gbar_nax * nax_gbar_axonm
axon.gbar_kdr = gbar_kdr * kdr_gbar_axonm
axon.gbar_kap = gbar_kap * kap_gbar_axonm
def set_calprops (self,sec):
sec.gcalbar_cal = cal_gcalbar
sec.gcanbar_can = can_gcanbar
sec.gpeak_kBK = kBK_gpeak
sec.caVhmin_kBK = -46.08 + kBK_caVhminShift
sec.depth_cadad = cadad_depth
sec.taur_cadad = cadad_taur
def set_somag (self):
sec = self.soma
sec.gbar_ih = gbar_h # Ih
self.set_calprops(sec)
sec.gbar_kdmc = gbar_kdmc
sec.gbar_nax = gbar_nax * nax_gbar_somam
def set_bdendg (self):
sec = self.Bdend
sec.gbar_ih = gbar_h # Ih
self.set_calprops(sec)
sec.gbar_nax = gbar_nax * nax_gbar_dendm
def set_apicg (self):
h.distance(0,0.5,sec=self.soma) # middle of soma is origin for distance
self.nexusdist = nexusdist = 300.0
self.h_gbar_tuftm = h_gbar_tuftm = h_gbar_tuft / gbar_h
self.h_lambda = h_lambda = nexusdist / log(h_gbar_tuftm)
for sec in self.apic:
self.set_calprops(sec)
for seg in sec:
d = h.distance(seg.x,sec=sec)
if d <= nexusdist: seg.gbar_ih = gbar_h * exp(d/h_lambda)
else: seg.gbar_ih = h_gbar_tuft
sec.gbar_nax = gbar_nax * nax_gbar_dendm
self.apic[1].gcalbar_cal = cal_gcalbar * calginc # middle apical dend gets more iL
# set properties
def set_props (self):
self.set_geom()
# cm - can differ across locations
self.axon.cm = axonCap
self.soma.cm = somaCap
self.Bdend.cm = bdendCap
for sec in self.apic: sec.cm = apicCap
# g_pas == 1.0/rm - can differ across locations
self.axon.g_pas = 1.0/axonRM
self.soma.g_pas = 1.0/somaRM
self.Bdend.g_pas = 1.0/bdendRM
for sec in self.apic: sec.g_pas = 1.0/apicRM
for sec in self.all_sec:
sec.ek = p_ek # K+ current reversal potential (mV)
sec.ena = p_ena # Na+ current reversal potential (mV)
sec.Ra = rall; sec.e_pas = Vrest # passive
sec.gbar_nax = gbar_nax # Na
sec.gbar_kdr = gbar_kdr # KDR
sec.vhalfn_kdr = kdr_vhalfn # KDR kinetics
sec.gbar_kap = gbar_kap # K-A
sec.vhalfn_kap = kap_vhalfn # K-A kinetics
sec.vhalfl_kap = kap_vhalfl
sec.tq_kap = kap_tq
self.set_somag()
self.set_bdendg()
self.set_apicg()
self.set_axong()
def insert_conductances (self):
for sec in self.all_sec:
sec.insert('k_ion')
sec.insert('na_ion')
sec.insert('pas') # passive
sec.insert('nax') # Na current
sec.insert('kdr') # K delayed rectifier current
sec.insert('kap') # K-A current
for sec in [self.Adend3, self.Adend2, self.Adend1, self.Bdend, self.soma]:
sec.insert('ih') # h-current
sec.insert('ca_ion') # calcium channels
sec.insert('cal') # cal_mig.mod
sec.insert('can') # can_mig.mod
sec.insert('cadad') # cadad.mod - calcium decay
sec.insert('kBK') # kBK.mod - ca and v dependent k channel
for sec in [self.soma, self.axon]: sec.insert('kdmc') # K-D current in soma & axon only
#
def prmstr (p,s,fctr=2.0,shift=5.0):
if p == 0.0:
print (s,'=',str(p-shift),str(p+shift),str(p),'True')
elif p < 0.0:
print (s, '=',str(p*fctr),str(p/fctr),str(p),'True')
else:
print (s, ' = ' , str(p/fctr), str(p*fctr), str(p), 'True')