Figure 3.

The frequency of spontaneous subthreshold oscillations in WT cells is determined by the electrically coupled network. Membrane potentials were altered by injecting steady currents, either hyperpolarizing or depolarizing, into WT (A) and KO (B) cells. C, Amplitudes of subthreshold oscillations were a strong function of membrane potential in both WT and KO neurons: summary of data from nine WT and nine KO cells. Mean amplitudes at various membrane potentials were scaled to largest responses and summed across 5-mV-wide bins, along with SE bars. The only significant difference was at the most hyperpolarized level (−66 to −70 mV), where the WT response was greater than the KO response (p < 0.05; t test). D, Oscillation frequency was a strong function of membrane polarization in neurons from the KO but was invariant with membrane potential in WT neurons. The graph shows data obtained from cells illustrated in A (WT) and B (KO). E, To summarize the voltage dependence of oscillation frequency, the best-fit line was calculated for each set of data points (as in D) (9 WT and 9 KO cells). The graph in E plots the slopes of the linear fits, in Hertz per millivolts. Dashed line shows slope of zero.