Developmental increase in hyperpolarization-activated current regulates intrinsic firing properties in rat vestibular ganglion cells

Identification and modelling of fast and slow Ih current components in vestibular ganglion neurons

“…(E) Firing patterns and hyperpolarisation sags of sustained and transient vestibular neurons models, provided with both I h components, in response to À120, À60, 20 and 40 pA current-clamp stimulation. The models reproduce actual data (Kalluri et al, 2010;Yoshimoto et al, 2015). AP latency could be strongly decreased by the activation of the I h current, due to depolarisation of the resting potential, and the EPSP time course also is decreased, sharpening the temporal response to transmitter release.…”

“…Figure 3E shows the responses of the vestibular ganglion neuron models (sustained, left panel and transient, right panel; see Materials and Methods) provided by both identified I h components, evoked by positive and negative current-clamp steps. The firing patterns differentiating the two basic categories of vestibular ganglion neurons (Kalluri et al, 2010;Yoshimoto et al, 2015) are well reproduced by the models (left and right upper panels). The sag which is known to reflect the presence of the I h currents in vestibular ganglion neurons (Chabbert et al, 2001b), in response to hyperpolarising current steps, is reproduced by the model in both neuron model types (left and right lower panels).…”

“…(E) Firing patterns and hyperpolarisation sags of sustained and transient vestibular neurons models, provided with both I h components, in response to −120, −60, 20 and 40 pA current‐clamp stimulation. The models reproduce actual data (Kalluri et al ., ; Yoshimoto et al ., ).…”

“…In addition, we tested the transient vestibular neuron model with the same protocols, but the large amplitude of a low-voltage-activated potassium current, probably composed of Kv1 and KCNQ channels, in this cell, precluded rebound firing of more than one AP, as already shown (Kalluri et al, 2010;Yoshimoto et al, 2015) whatever the activated I h component.…”

“…A single-compartment excitable neuron model was used to demonstrate the effects of the two I h currents identified in this study. The description of the membrane current flow follows models of cochlear nucleus neurons (Rothman & Manis, 2003a) in the auditory pathway, where maximal conductances are modified to reproduce the firing patterns of sustained and transient vestibular ganglion neurons (Kalluri et al, 2010;Yoshimoto et al, 2015). We added the I h components identified in this study to these models.…”