### Direction of current in point process

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**Tue Feb 06, 2018 3:43 pm**I am using a model for an Ornstein-Uhlenbeck Process (see below). It is defined as a point process. What does this imply regarding the direction of current? Is i > 0 depolarizing the cell, so that the equation for a one-compartment model would be c_m dV/dt = -I_ion

**+**I_syn or is it**-**I_syn?Code: Select all

```
INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}
NEURON {
POINT_PROCESS Gfluct
RANGE g_e, g_i, E_e, E_i, g_e0, g_i0, g_e1, g_i1
RANGE std_e, std_i, tau_e, tau_i, D_e, D_i
RANGE new_seed
NONSPECIFIC_CURRENT i
}
UNITS {
(nA) = (nanoamp)
(mV) = (millivolt)
(umho) = (micromho)
}
PARAMETER {
dt (ms)
E_e = 0 (mV) : reversal potential of excitatory conductance
E_i = -75 (mV) : reversal potential of inhibitory conductance
g_e0 = 0.0121 (umho) : average excitatory conductance
g_i0 = 0.0573 (umho) : average inhibitory conductance
std_e = 0.0030 (umho) : standard dev of excitatory conductance
std_i = 0.0066 (umho) : standard dev of inhibitory conductance
tau_e = 2.728 (ms) : time constant of excitatory conductance
tau_i = 10.49 (ms) : time constant of inhibitory conductance
}
ASSIGNED {
v (mV) : membrane voltage
i (nA) : fluctuating current
g_e (umho) : total excitatory conductance
g_i (umho) : total inhibitory conductance
g_e1 (umho) : fluctuating excitatory conductance
g_i1 (umho) : fluctuating inhibitory conductance
D_e (umho umho /ms) : excitatory diffusion coefficient
D_i (umho umho /ms) : inhibitory diffusion coefficient
exp_e
exp_i
amp_e (umho)
amp_i (umho)
}
INITIAL {
g_e1 = 0
g_i1 = 0
if(tau_e != 0) {
D_e = 2 * std_e * std_e / tau_e
exp_e = exp(-dt/tau_e)
amp_e = std_e * sqrt( (1-exp(-2*dt/tau_e)) )
}
if(tau_i != 0) {
D_i = 2 * std_i * std_i / tau_i
exp_i = exp(-dt/tau_i)
amp_i = std_i * sqrt( (1-exp(-2*dt/tau_i)) )
}
}
BREAKPOINT {
SOLVE oup
if(tau_e==0) {
g_e = std_e * normrand(0,1)
}
if(tau_i==0) {
g_i = std_i * normrand(0,1)
}
g_e = g_e0 + g_e1
g_i = g_i0 + g_i1
i = g_e * (v - E_e) + g_i * (v - E_i)
}
PROCEDURE oup() { : use Scop function normrand(mean, std_dev)
if(tau_e!=0) {
g_e1 = exp_e * g_e1 + amp_e * normrand(0,1)
}
if(tau_i!=0) {
g_i1 = exp_i * g_i1 + amp_i * normrand(0,1)
}
}
```