param gca=5.5 
param gk=8.0 
param gl=2.0 
param vca=115.0 
param vk=-84.0 
param vl=-55.0 
param c=20.0 
param phi=0.22 
param ic=90.0 
param v1=-1.2 
param v2=18.0 
param v3=2.0 
param v4=30.0 

state v=0
state w=0

aux minf = (1/2)*(1+tanh((v-v1)/v2))
aux winf = (1/2)*(1+tanh((v-v3)/v4))
aux tauw = 1/cosh((v-v3)/(2*v4))

v'= (1/c)*(ic-gca*minf*(v-vca) - gk*w*(v-vk) - gl*(v-vl))
w'= phi*(winf-w)/tauw

option tstop=100