from neuron import h, gui
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.colors as colors
import matplotlib.cm as cmx
import matplotlib.animation as animation
from matplotlib.animation import FuncAnimation
dtype = np.float64
# one-compartment cell (soma)
soma = h.Section(name='soma')
soma.diam = 50 # micron
soma.L = 63.66198 # micron, so that area = 10000 micron2
soma.nseg = 1 # adimensional
soma.cm = 1 # uF/cm2
soma.Ra = 70 # ohm-cm
soma.nseg = 1
soma.insert('na15') # insert mechanism
soma.ena = 65
h.celsius = 24 # temperature in celsius
v_init = -120 # holding potential
h.dt = 0.01 # ms - value of the fundamental integration time step, dt, used by fadvance().
# clamping parameters
dur = 500 # clamp duration, ms
step = 3 # voltage clamp increment
st_cl = -120 # clamp start, mV
end_cl = 1 # clamp end, mV
v_cl = -120 # actual voltage clamp, mV
#number of elements of the vector containing the values from st_cl to end_cl with the fixed step
L=len(np.arange(st_cl, end_cl, step))
# vectors for data handling
t_vec = h.Vector() # vector for time
v_vec = h.Vector() # vector for voltage
v_vec_t = h.Vector() # vector for voltage as function of time
i_vec = h.Vector() # vector for current
ipeak_vec = h.Vector() # vector for peak current
# a two-electrodes voltage clamp
f3cl = h.VClamp(soma(0.5))
f3cl.dur[0] = 40 # ms
f3cl.amp[0] = -120 # mV
f3cl.dur[1] = dur # ms
f3cl.amp[1] = v_cl # mV
f3cl.dur[2] = 20 # ms
f3cl.amp[2] = -10 # mV
# finding the "initial state variables values"
from state_variables import finding_state_variables
initial_values = [x for x in finding_state_variables(v_init,h.celsius)]
print('Initial values [C1, C2, O1, I1, I2]= ', initial_values)
for seg in soma:
seg.na15.iC1=initial_values[0]
seg.na15.iC2=initial_values[1]
seg.na15.iO1=initial_values[2]
seg.na15.iI1=initial_values[3]
seg.na15.iI2=initial_values[4]
### definizione figure
fig, ax = plt.subplots(1,3,figsize=(18,4))
ln0, = ax[0].plot([], [], '-')
ln1, = ax[1].plot([], [], '-')
ln2, = ax[2].plot([], [], '-')
fig.subplots_adjust(wspace=0.5)
fig.suptitle('2. Fast inactivation availability', fontsize=15, fontweight='bold')
def init():
ax[0].set_xlim(0,560)
ax[0].set_ylim(-121,10)
ax[0].set_xlabel('Time $(ms)$')
ax[0].set_ylabel('Voltage $(mV)$')
ax[0].set_title('Time/Voltage relation')
ax[1].set_xlim(0,560)
ax[1].set_ylim(-1.5,0.25)
ax[1].set_xlabel('Time $(ms)$')
ax[1].set_ylabel('Current density $(mA/cm^2)$')
ax[1].set_title('Time/Current density relation')
ax[2].set_xlim(-121,10)
ax[2].set_ylim(-1.5,0.25)
ax[2].set_xlabel('Voltage $(mV)$')
ax[2].set_ylabel('Current density $(mA/cm^2)$')
ax[2].set_title('Current density/Voltage relation')
return ln0, ln1, ln2,
#to plot in rainbow colors
values =range(L)
rbw = cm = plt.get_cmap('rainbow')
cNorm = colors.Normalize(vmin=0, vmax=values[-1])
scalarMap = cmx.ScalarMappable(norm=cNorm, cmap=rbw)
# animation definition
def animate(frame):
ran=np.arange(st_cl, end_cl, step)
v_cl2=ran[int(frame)]
#resizing vectors
t_vec.resize(0)
i_vec.resize(0)
v_vec_t.resize(0)
clamp(v_cl2)
colorVal1 = scalarMap.to_rgba(values[int(frame)])
colorVal2 = scalarMap.to_rgba(values[0:int(frame)+2])
ln0,=ax[0].plot(t_vec, v_vec_t,color=colorVal1)
ln1,=ax[1].plot(t_vec, i_vec,color=colorVal1)
ln2=ax[2].scatter(v_vec, ipeak_vec, c=colorVal2)
return ln0, ln1, ln2
# clamping definition
def clamp(v_cl):
f3cl.dur[1]=dur # ms
f3cl.amp[1]=v_cl # mV
h.finitialize(v_init)
peak_curr = 0
dens = 0
t_peak = 0
while (h.t<h.tstop): # runs a single trace, calculates peak current
dens = f3cl.i/soma(0.5).area()*100.0-soma(0.5).i_cap # clamping current in mA/cm2, for each dt
t_vec.append(h.t) # code for store the current
v_vec_t.append(soma.v) # trace to be plotted
i_vec.append(dens) # trace to be plotted
if ((h.t>=540)and(h.t<=542)): # evaluate the peak
if(abs(dens)>abs(peak_curr)):
peak_curr = dens # updates the peak current
t_peak = h.t
h.fadvance()
if len(v_vec) > L-1: #resizing v_vec and ipeak_vec when the protocol is completed (it is needed for looping the animation)
v_vec.resize(0)
ipeak_vec.resize(0)
v_vec.append(v_cl) # updates the vectors at the end of the run
ipeak_vec.append(peak_curr)
def start():
h.tstop = 40 + dur + 20 # time stop
v_vec.resize(0)
ipeak_vec.resize(0)
#animation
ani = animation.FuncAnimation(fig, animate, frames=L,
init_func=init, blit=True, interval=500, repeat=True)
plt.show()
start()