Figure 2.

(a) Schematic of the lattice. Cells are referred to using i, j coordinates; the resistance between cells is denoted by R. The resistances are converted into dimensionless coupling values as detailed in §2.2.3. (b,c) The resistance of a gap junction. (b) The resistance r_i across an individual connexon (consisting of six connexins). (c) A number of connexons link the two cells. The individual connexons act in parallel, giving an equivalent resistance R. (d) Electrical circuit diagram representing the current flow between connected cells. Cell (i, j) is the cell of interest, coupled to four surrounding cells; R represents the resistances in gap junctions. The circuit at cell (i, j) represents a basic model of an excitable system [28]. V_e represents the external potential, V_i represents the internal potential, C_i,j is the cell capacitance, the excitable element represents the recovery current and the nonlinear current–voltage device (I) represents the fast current. (e) Asymmetry in coupling due to different cell sizes κ₁ > κ₂.