The edPR model is "what we may refer to as “a minimal neuronal model that has it all”. By “has it all”, we mean that it (1) has a spatial extension, (2) considers both extracellular- and intracellular dynamics, (3) keeps track of all ion concentrations (Na+, K+, Ca2+, and Cl-) in all compartments, (4) keeps track of all electrical potentials in all compartments, (5) has differential expression of ion channels in soma versus dendrites, and can fire somatic APs and dendritic calcium spikes, (6) contains the homeostatic machinery that ensures that it maintains a realistic dynamics in the membrane potential and all ion concentrations during long-time activity, and (7) accounts for transmembrane, intracellular and extracellular ionic movements due to both diffusion and electrical migration, and thus ensures a consistent relationship between ion concentrations and electrical charge. Being based on a unified framework for intra- and extracellular dynamics, the model thus accounts for possible ephaptic effects from extracellular dynamics, as neglected in standard feedforward models based on volume conductor theory. By “minimal” we simply mean that we reduce the number of spatial compartments to the minimal, which in this case is four, i.e., two neuronal compartments (a soma and a dendrite), plus two extracellular compartments (outside soma and outside dendrite). Technically, the model was constructed by adding homeostatic mechanisms and ion concentration dynamics to an existing model, i.e., the two-compartment Pinsky-Rinzel (PR) model, and embedding in it a consistent electrodiffusive framework, i.e., the previously developed Kirchhoff-Nernst-Planck framework."
Model Type: Extracellular; Neuron or other electrically excitable cell
Region(s) or Organism(s): Hippocampus
Cell Type(s): Pinsky-Rinzel CA1/3 pyramidal cell
Currents: I Sodium; I Potassium; I Calcium; I K,Ca; I_AHP; I Na, leak; I K,leak; I Cl, leak; Na/K pump; KCC2; NKCC1; Na/Ca exchanger
Model Concept(s): Detailed Neuronal Models; Homeostasis; Depolarization block; Action Potentials; Electrodiffusion
Simulation Environment: Python
References:
Sætra MJ, Einevoll GT, Halnes G. (2020). An electrodiffusive, ion conserving Pinsky-Rinzel model with homeostatic mechanisms PLoS Computational Biology.