membrane potential dependency from ion concentrations?
Posted: Mon Nov 26, 2018 4:07 pm
Hello everybody,
In my thesis i will work with NEURON. In order to understand the NEURON simulations better, i refresh my neurophysiology knownledge. Thereby, some questions came up, i stuck with. May you can help me.
For example, if i increase the internal potassium concentration (for example by current injection), the cell will hyperpolarize according to Goldman Equation (and the increased chemical gradient). My problem is that i would assume the increased potassium concentration in the cell would have depolarized the cell in the first place. Is there any way i can visualize this? Same problem with injection of potassium outside the cell but vice versa.
My second question might can help elucidate my first question: The Goldman Equation only considers Ions for which the membran has permability. What If i would increase for example the outside calcium concentration (or the concentration of any other ion the cell has little/no permability for)? Would the change in concentration of this ion affect the membrane potential?
I have not discovered any features of NEURON, which considers ion concentrations directly (only the ion-conductancies and potentials). Is there no need for it? Is the cell described sufficiently by specification of the membrance conductance and the equilibrium potential of this neuron?
I would really appreciate help as i am stucked.
With kind regards,
Bonic
In my thesis i will work with NEURON. In order to understand the NEURON simulations better, i refresh my neurophysiology knownledge. Thereby, some questions came up, i stuck with. May you can help me.
For example, if i increase the internal potassium concentration (for example by current injection), the cell will hyperpolarize according to Goldman Equation (and the increased chemical gradient). My problem is that i would assume the increased potassium concentration in the cell would have depolarized the cell in the first place. Is there any way i can visualize this? Same problem with injection of potassium outside the cell but vice versa.
My second question might can help elucidate my first question: The Goldman Equation only considers Ions for which the membran has permability. What If i would increase for example the outside calcium concentration (or the concentration of any other ion the cell has little/no permability for)? Would the change in concentration of this ion affect the membrane potential?
I have not discovered any features of NEURON, which considers ion concentrations directly (only the ion-conductancies and potentials). Is there no need for it? Is the cell described sufficiently by specification of the membrance conductance and the equilibrium potential of this neuron?
I would really appreciate help as i am stucked.
With kind regards,
Bonic