#
'''
The MSN class defining the cell
'''
from neuron import h
import numpy as np
import json
# Distributions:
'''
T-type Ca: g = 1.0/( 1 +np.exp{(x-70)/-4.5} )
naf (den): (0.1 + 0.9/(1 + np.exp((x-60.0)/10.0)))
'''
def calculate_distribution(d3, dist, a4, a5, a6, a7, g8):
'''
Used for setting the maximal conductance of a segment.
Scales the maximal conductance based on somatic distance and distribution type.
Parameters:
d3 = distribution type:
0 linear,
1 sigmoidal,
2 exponential
3 step function
dist = somatic distance of segment
a4-7 = distribution parameters
g8 = base conductance (similar to maximal conductance)
'''
if d3 == 0:
value = a4 + a5*dist
elif d3 == 1:
value = a4 + a5/(1 + np.exp((dist-a6)/a7) )
elif d3 == 2:
value = a4 + a5*np.exp((dist-a6)/a7)
elif d3 == 3:
if (dist > a6) and (dist < a7):
value = a4
else:
value = a5
if value < 0:
value = 0
value = value*g8
return value
# ======================= the MSN class ==================================================
class MSN:
def __init__(self, params=None, \
morphology=None, \
variables=None, \
section=None ):
Import = h.Import3d_SWC_read()
Import.input(morphology)
imprt = h.Import3d_GUI(Import, 0)
imprt.instantiate(None)
h.define_shape()
# h.cao0_ca_ion = 2 # default in nrn
h.celsius = 35
self._create_sectionlists()
self._set_nsegs(section=section)
self.v_init = -80
self.dendritic_channels = [
"naf",
"kaf",
"kas",
"kdr",
"kir",
"cal12",
"cal13",
"can",
"car",
"cav32",
"cav33",
"sk",
"bk" ]
self.somatic_channels = [
"naf",
"kaf",
"kas",
"kdr",
"kir",
"cal12",
"cal13",
"can",
"car",
"sk",
"bk" ]
self.axonal_channels = [
"naf",
"kas" ,
"Im" ]
# insert active mechanisms (related to channels) -------------
for sec in self.somalist:
for mech in self.somatic_channels+["cadyn", "caldyn"]:
sec.insert(mech)
for sec in self.axonlist:
for mech in self.axonal_channels:
sec.insert(mech)
for sec in self.dendlist:
for mech in self.dendritic_channels+["cadyn", "caldyn"]:
sec.insert(mech)
with open(params) as file:
par = json.load(file)
# set passive parameters --------------------------------------------
for sec in self.allseclist:
sec.Ra = 150
sec.cm = 1.0
sec.insert('pas')
#sec.g_pas = 1e-5 # set using json file
sec.e_pas = -70 # -73
sec.g_pas = float(par['g_pas_all']['Value'])
sec.ena = 50
sec.ek = -85 # -90
self.distribute_channels("soma", "gbar_naf", 0, 1, 0, 0, 0, float(par['gbar_naf_somatic']['Value']))
self.distribute_channels("soma", "gbar_kaf", 0, 1, 0, 0, 0, float(par['gbar_kaf_somatic']['Value']))
self.distribute_channels("soma", "gbar_kas", 0, 1, 0, 0, 0, float(par['gbar_kas_somatic']['Value']))
self.distribute_channels("soma", "gbar_kdr", 0, 1, 0, 0, 0, float(par['gbar_kdr_somatic']['Value']))
self.distribute_channels("soma", "gbar_bk", 0, 1, 0, 0, 0, float(par['gbar_bk_somatic' ]['Value']))
self.distribute_channels("soma", "pbar_cal12", 0, 1, 0, 0, 0, 1.34e-5)
self.distribute_channels("soma", "pbar_cal13", 0, 1, 0, 0, 0, 1.34e-6)
self.distribute_channels("soma", "pbar_car", 0, 1, 0, 0, 0, 1.34e-4)
self.distribute_channels("soma", "pbar_can", 0, 1, 0, 0, 0, 4e-5)
self.distribute_channels("dend", "gbar_kdr", 0, 1, 0, 0, 0, float(par['gbar_kdr_basal']['Value']))
self.distribute_channels("dend", "gbar_bk", 0, 1, 0, 0, 0, float(par['gbar_bk_basal' ]['Value']))
self.distribute_channels("dend", "pbar_cal12", 0, 1, 0, 0, 0, 1e-5)
self.distribute_channels("dend", "pbar_cal13", 0, 1, 0, 0, 0, 1e-6)
self.distribute_channels("dend", "pbar_car", 0, 1, 0, 0, 0, 1e-4)
self.distribute_channels("axon", "gbar_kas", 0, 1, 0, 0, 0, float(par['gbar_kas_axonal']['Value']))
self.distribute_channels("axon", "gbar_naf", 3, 1, 1.1, 30, 500, float(par['gbar_naf_axonal']['Value']))
self.distribute_channels("axon", "gbar_Im", 0, 1, 0, 0, 0, 1.0e-3)
# in ephys step functions are not supported so something like below formula will be used instead.
#self.distribute_channels("axon", "gbar_naf", 1, 1, 0.1, 30, -1, float(par['gbar_naf_axonal']['Value']))
#(1 + 0.9/(1 + math.exp(({distance}-30.0)/-1.0) ))
if variables:
self.distribute_channels("dend", "gbar_naf", 1, 1.0-variables['naf'][1], \
variables['naf'][1], \
variables['naf'][2], \
variables['naf'][3], \
np.power(10,variables['naf'][0])*float(par['gbar_naf_basal']['Value']))
self.distribute_channels("dend", "gbar_kaf", 1, 1.0, \
variables['kaf'][1], \
variables['kaf'][2], \
variables['kaf'][3], \
np.power(10,variables['kaf'][0])*float(par['gbar_kaf_basal']['Value']))
self.distribute_channels("dend", "gbar_kas", 1, 0.1, \
0.9, \
variables['kas'][1], \
variables['kas'][2], \
np.power(10,variables['kas'][0])*float(par['gbar_kas_basal']['Value']))
self.distribute_channels("dend", "gbar_kir", 0, np.power(10,variables['kir'][0]), 0, 0, 0, float(par['gbar_kir_basal' ]['Value']))
self.distribute_channels("soma", "gbar_kir", 0, np.power(10,variables['kir'][0]), 0, 0, 0, float(par['gbar_kir_somatic']['Value']))
self.distribute_channels("dend", "gbar_sk", 0, np.power(10,variables['sk' ][0]), 0, 0, 0, float(par['gbar_sk_basal' ]['Value']))
self.distribute_channels("soma", "gbar_sk", 0, np.power(10,variables['sk' ][0]), 0, 0, 0, float(par['gbar_sk_somatic' ]['Value']))
self.distribute_channels("dend", "pbar_can", 1, 1.0-variables['can'][1], \
variables['can'][1], \
variables['can'][2], \
variables['can'][3], \
np.power(10,variables['can'][0]))
self.distribute_channels("dend", "pbar_cav32", 1, 0, \
1, \
variables['c32'][1], \
variables['c32'][2], \
np.power(10,variables['c32'][0]))
self.distribute_channels("dend", "pbar_cav33", 1, 0, \
1, \
variables['c33'][1], \
variables['c33'][2], \
np.power(10,variables['c33'][0]))
else:
self.distribute_channels("dend", "gbar_naf", 1, 0.1, 0.9, 60.0, 10.0, float(par['gbar_naf_basal']['Value']))
self.distribute_channels("dend", "gbar_kaf", 1, 1, 0.5, 120.0, -30.0, float(par['gbar_kaf_basal']['Value']))
self.distribute_channels("dend", "gbar_kas", 2, 1, 9.0, 0.0, -5.0, float(par['gbar_kas_basal']['Value']))
self.distribute_channels("dend", "gbar_kir", 0, 1, 0, 0, 0, float(par['gbar_kir_basal']['Value']))
self.distribute_channels("soma", "gbar_kir", 0, 1, 0, 0, 0, float(par['gbar_kir_somatic']['Value']))
self.distribute_channels("dend", "gbar_sk", 0, 1, 0, 0, 0, float(par['gbar_sk_basal']['Value']))
self.distribute_channels("soma", "gbar_sk", 0, 1, 0, 0, 0, float(par['gbar_sk_basal']['Value']))
self.distribute_channels("dend", "pbar_can", 0, 1, 0, 0, 0, 1e-7)
self.distribute_channels("dend", "pbar_cav32", 1, 0, 1.0, 120.0, -30.0, 1e-7)
self.distribute_channels("dend", "pbar_cav33", 1, 0, 1.0, 120.0, -30.0, 1e-8)
def _create_sectionlists(self):
self.allsecnames = []
self.allseclist = h.SectionList()
for sec in h.allsec():
self.allsecnames.append(sec.name())
self.allseclist.append(sec=sec)
self.nsomasec = 0
self.somalist = h.SectionList()
for sec in h.allsec():
if sec.name().find('soma') >= 0:
self.somalist.append(sec=sec)
if self.nsomasec == 0:
self.soma = sec
self.nsomasec += 1
self.axonlist = h.SectionList()
for sec in h.allsec():
if sec.name().find('axon') >= 0:
self.axonlist.append(sec=sec)
self.dendlist = h.SectionList()
for sec in h.allsec():
if sec.name().find('dend') >= 0:
self.dendlist.append(sec=sec)
def _set_nsegs(self, section=None, N=20):
""" def seg/sec. if section: set seg ~= 1/um """
if section:
dend_name = 'dend[' + str(int(section)) + ']'
for sec in self.allseclist:
if sec.name() == dend_name:
# TODO: this needs some thinking; how to best set number of segments
n = 2*int(sec.L/2.0)+1
if n > N:
sec.nseg = n
else:
sec.nseg = 2*(N/2) + 1 # odd number of seg
else:
sec.nseg = 2*int(sec.L/40.0)+1
else:
for sec in self.allseclist:
sec.nseg = 2*int(sec.L/40.0)+1
for sec in self.axonlist:
sec.nseg = 2 # two segments in axon initial segment
def distribute_channels(self, as1, as2, d3, a4, a5, a6, a7, g8):
h.distance(sec=self.soma)
for sec in self.allseclist:
# if right cellular compartment (axon, soma or dend)
if sec.name().find(as1) >= 0:
for seg in sec:
dist = h.distance(seg.x, sec=sec)
val = calculate_distribution(d3, dist, a4, a5, a6, a7, g8)
cmd = 'seg.%s = %g' % (as2, val)
exec(cmd)