#  Hodgkin-Huxley model
#  
#  Istimulus : applies stimulus of amplitude 'ampl' in the time interval [a,b]
#
#   March 30, 2007


@ MAXSTOR=40000
@ YP=n
@ XP=v
@ TOTAL=300
@ DT=0.05
@ BOUND=1000000
@ XLO=-100
@ XHI=100
@ YLO=-0.1
@ YHI=1.1
@ METH=gear

par I=0

par a=100, b=200, ampl=0

Istimul(s)=ampl*heav(s-a)*heav(b-s)

an(v) = 0.01*(-v+10)/(exp(-0.1*v+1)-1)
bn(v) = 0.125*exp(-v/80)

am(v) = 0.1*(-v+25)/(exp(-0.1*v+2.5)-1)
bm(v) = 4*exp(-v/18)

ah(v) = 0.07*exp(-v/20)
bh(v) = 1/(exp(-0.1*v+3)+1)

dv/dt = Istimul(s) + I + 36*n^4*(-12-v)+120*m^3*h*(120-v)+ 0.3*(10.6-v)
dn/dt = an(v)*(1-n)-bn(v)*n
dm/dt = am(v)*(1-m)-bm(v)*m
dh/dt = ah(v)*(1-h)-bh(v)*h
ds/dt=1

init v=-0.2828,  n=0.3208, m=0.0513, h=0.5841, s=0

done