Figure 4.

Electrode fitting and response dynamics of second-order vestibular neurons (2°VN) and abducens motoneuron (AbMot) using Piece-wise Non-linear Electrode Compensation (PNEC). (A) Electrode fitting procedure of the responses in an AbMot at I_hold = +1 nA; the electrode admittance Y_e (solid line) changed after the electrode was removed from the neuron and was shifted (G_T + Y_e) in order to overlap at high frequencies with the properties of the electrode + neuron admittance Y_n + e; plotted frequency spectrum 0.2–980 Hz. (B1,B2–D1,D2) Impedance profiles and corresponding phase relations of the responses at several holding currents (I_hold) of an AbMot (B1,B2), a tonic (C1,C2) and two different phasic 2°VN (D1,D2,E1,E2) after PNEC; responses of the phasic 2°VN shown in (D1,D2) were measured before and after bath application of 4-aminopyridine (4AP; 20 μM) [dotted lines in (D1,D2)] with PNEC; responses of the phasic 2°VN shown in (E1,E2) were measured after PNEC as well as during standard bridge compensation (BC) of the amplifier [dotted lines in (E1,E2)]; legends in (B1–E1) also apply to (B2–E2).