# Electrophysiological Characterization of Murine Vestibular Efferent Neurons and Modulation by Acute Peripheral Vestibular Deprivation

## TL;DR

This study explores how brainstem neurons that control inner ear function behave and change when the inner ear is temporarily disabled.

## Contribution

The study identifies the electrophysiological properties and neuromodulatory regulation of murine vestibular efferent neurons.

## Key findings

- Vestibular efferent neurons show spontaneous firing with diverse discharge patterns and after-hyperpolarization.
- A-type potassium currents are modulated by acetylcholine and calcitonin gene-related peptide.
- Acute vestibular deprivation increases spontaneous firing bilaterally, suggesting adaptive plasticity.

## Abstract

Vestibular efferent neurons in the brainstem provide direct cholinergic innervation to peripheral vestibular organs, thereby modulating their sensory responsiveness. In this study, a genetically targeted mouse model with choline acetyltransferase-driven fluorescent labeling enabled the precise localization of these neurons to the dorsolateral region of the genu of the facial nerve. Whole-cell patch-clamp recordings in acute brainstem slices revealed that virtually all neurons exhibited spontaneous action potential firing, with marked heterogeneity in discharge patterns and after-hyperpolarization kinetics. Prominent A-type potassium currents were identified and found to be differentially regulated by acetylcholine and calcitonin gene-related peptide. Acute unilateral vestibular deprivation induced a bilateral enhancement of spontaneous firing, indicating sensitivity to altered sensory input. These findings define the intrinsic electrophysiological properties and neuromodulatory mechanisms of vestibular efferent neurons, providing mechanistic insight into their roles in both physiological regulation and adaptive plasticity within the vestibular system.