Patent ID: 8180617

Claim:
A computer-based method for computing a spatial charge distribution for at least a portion of an electrophysiological system that comprises a biological membrane having an intracellular side and an extracellular side, said method comprising: (I) inputting data to a computer regarding (i) the structure and dimensions of the portion of the electrophysiological system, (ii) at least one electrical property of the portion of the electrophysiological system, and (iii) the value V Nernst of at least one Nernst potential between the intracellular and extracellular sides of the biological membrane; (II) using the computer to: (a) represent said portion of the electrophysiological system by a plurality of cubic calculation cells, each calculation cell having six faces and edges of length s; (b) represent a non-conservative field E′ n at a face of at least one calculation cell by an equation of the form: E′ n =−V Nernst /s, said face having an outward normal that points from the intracellular side of the face towards the extracellular side of the face; (c) represent a non-conservative field E′ n at a face of at least one calculation cell by an equation of the form: E′ n =+V Nernst /s said face having an outward normal that points from the extracellular side of the face towards the intracellular side of the face; and (d) determine the spatial charge distribution for said portion of the electrophysiological system using (i) the plurality of cubic calculation cells, (ii) the representations of the non-conservative field, and (iii) a 1/r 2 law to express at least some of the electrophysiological system's electrical fields, where r represents a distance to a quantity of charge, said spatial charge distribution being determined without first determining and differentiating an electrical potential distribution; and (III) displaying at least a part of the spatial charge distribution for said portion of the electrophysiological system determined in step (II)(d).