# voltage clamp -- lots of nice experiments
aux vprofile=v
aux I=gnabar*h*(v-vna)*m^3+gkbar*n^4*(v-vk)+gl*(v-vl)+vfp(t)
aux ina=gnabar*h*(v-vna)*m^3
aux ik=gkbar*n^4*(v-vk)
aux il=gl*(v-vl)
aux gna=gnabar*h*m^3
aux gk=gkbar*n^4
am(v)=.1*(v+40)/(1-exp(-(v+40)/10))
bm(v)=4*exp(-(v+65)/18)
ah(v)=.07*exp(-(v+65)/20)
bh(v)=1/(1+exp(-(v+35)/10))
an(v)=.01*(v+55)/(1-exp(-(v+55)/10))
bn(v)=.125*exp(-(v+65)/80)
v=vf(t)
step(x)=.5*(1+tanh(x*shp))
stepp(x)=.5*shp*(1-tanh(x*shp)^2)
vf(t)=vhold+(vclamp-vhold)*step(t-t1)*step(t2-t)
vfp(t)=(vclamp-vhold)*(stepp(t-t1)*step(t2-t)-step(t-t1)*stepp(t2-t))
m'=am(v)*(1-m)-bm(v)*m
m(0)=.093
h'=ah(v)*(1-h)-bh(v)*h
h(0)=.418
n'=an(v)*(1-n)-bn(v)*n
n(0)=.396
par vhold=-60,vclamp=0,v2=0,shp=80
par t1=2,t2=10,t3=1000,t4=1200
par vna=50  vk=-77  vl=-54.4  gnabar=120  gkbar=36  gl=0.3  c=1 
@ bounds=10000,total=45,xlo=0,xhi=12,ylo=-2000,yhi=5000,yp=I
@ t0=-30
done