Functional Imaging of the Vestibular System

Abstract

This chapter focuses on current knowledge of multisensory vestibular structures and their functions in the human cortex. Most derives from brain activation studies conducted over the last decade with PET and fMRI. These tools have confirmed that humans have several separate and distinct cortical areas that tracer and electrophysiological studies in animals, especially in monkeys, had identified earlier. The patterns of activations and deactivations during vestibular stimulations in healthy subjects have been compared with those in patients with acute and chronic peripheral and central vestibular disorders. In this way much has been learned about the interconnections of vestibular structures, their activations and interactions with other sensory modalities, the correlations of perceptual and motor functions in normal humans, and the changes that result from strategic peripheral and central vestibular lesions such as vestibular neuritis and bilateral vestibular failure, on the one hand, and central vestibular nucleus lesions due to ischemic infarctions of the lateral medulla (Wallenberg’s syndrome), on the other.