Figure 3.

Response dynamics of phasic 2°VNs. A₁–A₃, Typical examples of impedance profiles of three different phasic 2°VNs calculated from responses to injection of small-amplitude ZAP currents. Based on their shape, responses were classified as nonresonant (A₁), simple resonant (A₂), or trough resonant (A₃). Simple-resonant responses exhibit a single resonance peak (*), and trough-resonant responses exhibit a trough-like depression (black diamond) before the resonance peak (**). Horizontal dashed lines indicate resting membrane potential (−67 mV in A₁; −66 mV in A₂; −63 mV in A₃). Calibration in A₃ applies to A₁ and A₂. B, Bode plots comparing impedance and phase profiles of all phasic (filled circles) and tonic (filled stars) 2°VNs; phasic neurons were further separated as nonresonant (gray circles), simple resonant (gray circles), and trough resonant (gray triangles).V, Voltage; F, frequency; C, current.