Figure 3.

Spherical cell model (r_cell = 10 μm) for nearly insulating and realistic membrane resistivities. (a) Perspective drawing with ideal parallel plane electrodes (top black and bottom gray) that provide an applied electric field, E⃗_app. (b) Approximation of spherical cell (black region assigned M_e1+m+e2; white and gray regions assigned M_e1 and M_e2, respectively). (c–h) Equipotentials (blue) for ρ_m = 10⁸ Ω m and f = 100 Hz, 100 kHz, 1 MHz, 10 MHz, 100 MHz, and 1 GHz, respectively. (i) Magnitude of the frequency-dependent membrane field gain at the cell's poles, G_m,pole(f), predicted here (red) and by a second-order analytic model (black) (29).