Peripheral vestibular plasticity vs central compensation: evidence and questions.

Over the last few decades, several studies have been conducted to identify the mechanisms involved in spontaneous functional recovery following peripheral vestibular damage. Different reactive processes occur at both the central and peripheral levels over the first few hours after the loss of the peripheral vestibular input. The restoration of the electrophysiological homeostasis between opposite vestibular nuclei is one of the key mechanisms of central compensation. This is achieved through a mosaic of biochemical events within the vestibular nuclei that each occur with their own kinetics. At the same time, under specific conditions, strong synaptic plasticity may take place within the vestibular sensory organs. It is thought that this reactive plasticity can contribute to the repair of damaged contacts between hair cells and fibres of the vestibular nerve, thus gradually restoring peripheral sensory input. These different plastic phenomena seem to reproduce those observed during development. Research is now needed to identify the cellular and molecular mechanisms that support this spontaneous peripheral repair process, with the ambition 1 day to be able to control it and stimulate the restoration of gait and balance.