% A minimal model of the dopamine neuron, from Li etal, Neuroscience, 
% 71:397-410, 1996. 
variables Vs=-64.0,h=1.0,n=0.002,r=0.12,Vd=-77.0,Na=5.09
params vl=-50.0,cm=1.0,vk=-85.0
params gna=3.2,gk=3.2,gh=0.1,gc=0.1,p=0.5,rd=1.0,iap=0.0,kna=15.0,Nass=8.0,gnmdab=1.25,gnmdanab=1.0

% Dendrite functions
user gnmda 1 gnmdab*(p/(1-p))
user gnmdana 1 gnmdanab*(p/(1-p))
user gl 1 0.18*(p/(1-p))
user ipumpmx 1 18.0*(p/(1-p))
user fd 1 0.173
user fnmda 1 1.0/(1.0+0.14*exp(-arg1/12.5))  

% Current functions
user minf 1 1.0/(1.0+exp((-35.0-arg1)/6.2))
user ninf 1 1.0/(1.0+exp((-31.0-arg1)/5.3))
user hinf 1 1.0/(1.0+exp((arg1+30.0)/8.3))
user rinf 1 1.0/(1.0+exp((arg1+80.0)/8.0))
user tauh 1 0.43 + 0.86/(1.0+exp((arg1+25.0)/5.0))
user taun 1 (0.8+1.6/(1.0+exp(0.1*(arg1+25.0)))) / (1.0+exp(-0.1*(arg1+70.0)))
%user taun 1 (0.43+1.075/(1.0+exp(0.1*(arg1+25.0)))) * (exp(0.1*(arg1+70.0))/(1.0+exp(0.1*(arg1+70.0))))
user taur 1 190.0

% Currents
user ina 2 gna*(minf(arg1)^3)*arg2*(arg1-55.0) 
user ik 2 gk*(arg2^2)*(arg1-vk)
user ih 2 gh*arg2*(arg1+30.0) 
user inmda 1 gnmda(arg1)*fnmda(arg1)*arg1  
user inmdana 1 gnmdana(arg1)*fnmda(arg1)*(arg1-55.0) 
user ipump 1 ipumpmx(arg1)*((arg1+Nass)^3 / (kna^3+(arg1+Nass)^3))
user ipumpss 1 ipumpmx(arg1)*(Nass^3 / (kna^3+Nass^3))
user il 1 gl(arg1)*(arg1-vl) 
user isoma 4 ina(arg1,arg2) + ik(arg1,arg3) + ih(arg1,arg4) 
user iden 2 inmda(arg1) + ipump(arg2) - ipumpss(arg1) + il(arg1) 

% Differential equations
odeVs  (iap-isoma(Vs,h,n,r)+(gc/p)*(Vd-Vs))/cm
odeh   (hinf(Vs)-h)/tauh(Vs)
oden   (ninf(Vs)-n)/taun(Vs)
oder   (rinf(Vs)-r)/taur(Vs)
odeVd  (-iden(Vd,Na)+(gc/(1-p))*(Vs-Vd))/cm
odeNa  -fd(Vd)*(inmdana(Vd)+3.0*(ipump(Na)-ipumpss(Vd)))
done