An inhibitory current (actual Erev = −70 mV) was evoked at varying distances from the recording site 0 µm. (A–F) All plots show apparent Erevs as a function of gmax (1, 5, 10, 50 nS) for all 20 passive cable models (in gray), varying in their membrane and axial resistances (see Materials and methods). The data points in color denote the same cable model presented in Figure 6, with a passive conductance of 20 nS·cm−2 and axial resistance of 30 Ω·cm (as indicated in key at top). The cable diagrams above each plot indicate the recording and activation sites. (A) When measured at the site of activation (0 µm), the apparent Erev is equivalent to the actual Erev, regardless of gmax or passive properties. B–F When the inhibitory current is activated at 200 (B), 400 (C), 600 (D), 800 (E), or 1000 (F) µm away, the apparent Erev measured at 0 µm is independent of gmax, but does vary with passive properties.