Alteration of the oscillation frequency (fpyloric) of the PD neuron by shifting its membrane resonance frequency fmax using the dynamic-clamp technique. A, Adding or subtracting gCa shifts both fmax and fpyloric. A1, Voltage traces of the PD neuron during ongoing oscillations in normal saline (top traces) and in response to a ZAP current applied in TTX (bottom traces). The left column shows the effect of subtracting a dynamic-clamp artificial ICa, and the right column shows the effect of adding ICa (see Results). The resting membrane potentials for the traces were −55, −48, and −39 mV, respectively. A2, Impedance profiles measured from traces in A1, shown as a function of frequency. B, Adding or subtracting gh shifts both fmax and fpyloric. B1, As in A1, the left column shows the effect of subtracting a dynamic-clamp artificial Ih, and the right column shows the effect of adding Ih (see Results). The resting membrane potentials for the traces were −57, −48, and −41 mV, respectively. B2, Impedance profiles measured from traces in B1, shown as a function of frequency. C, Normalized changes in fpyloric induced by changing either ICa or Ih are correlated to normalized changes in fmax corresponding to the subtraction or addition of the same dynamic-clamp artificial currents. The dashed line shows a linear fit of data points (R2 = 0.57 ± 0.088; p = 0.001; n = 5 experiments; up to 6 negative and 6 positive conductance values were done in each experiment). The filled circle (−gdyn) shows the average change obtained by the subtraction of dynamic-clamp artificial currents (Δfpyloric/fpyloric = −0.035 ± 0.016 and Δfmax/fmax = −0.36 ± 0.072), and the open square (+gdyn) shows the average obtained by the addition of dynamic-clamp artificial currents (Δfpyloric/fpyloric = 0.081 ± 0.016 and Δfmax/fmax = 0.581 ± 0.115) for both ICa and Ih.