Figure 4.

Voltage dependence of g_K activation. The circles correspond to the experiment illustrated in figure 1. The I_o results from those records were normalized by GHK[(V−E_K)]. The values of that procedure reached saturation at +5 mV. The points at 5, 15, 25 and 35 mV were averaged, and that average value was used to normalize the results a second time so that this relation for V≥5 mV corresponds to unity. The curve labelled ‘HH $n_{\infty }^4(V)$’ represents $n_{\infty }^4(V)$ in the HH (1952d) model, where n_∞(V)=α_n/(α_n+β_n). The curve labelled ‘$n_{\infty }^4(V)$ revised’ is the prediction of the model using the modified β_n described in the text (V_o=19.7 mV as opposed to 80 mV in the HH model).