The dorsolateral prefrontal cortex as a potential target for electrical stimulation in the treatment of vestibular-based nausea.

As a result of its location (facilitating ease of access) and its multimodal nature, the dorsolateral prefrontal cortex (dlPFC) is a commonly targeted site for transcranial electrical and magnetic stimulation in the treatment of psychiatric disorders. However, this cortical region has many interconnections throughout the brain, overlapping with other systems. One such example is the vestibular system. Starting at the vestibular organs within the inner ear, the vestibular system plays a major role in nauseogenic responses, and many vestibular disorders do not have well-documented treatment plans. Given the overlapping circuitry between the dlPFC and vestibular processing networks, it has been hypothesised that the two would have interactions with one another when stimulated. Indeed, recent work has shown transcranial alternating current stimulation of the dlPFC to have an inhibitory action on sinusoidal galvanic vestibular stimulation-induced nausea and perceptions of motion. Furthermore, stimulating the dlPFC through transcranial direct current stimulation has reduced dizziness in a cohort of phobic postural vertigo patients. This review aims to introduce the vestibular system and vestibular-based nausea, including the cortical processing network, before discussing the dlPFC as a potential site for therapeutic targeting in various vestibular-related disease states. This targeting focusses on transcranial stimulation, first in vestibular disorders, then in generalised motion sickness, concluding with speculation upon its possible (though perhaps less probable) 'blue-sky' use in chemotherapy-induced nausea and vomiting.