Vestibular cortex activation during locomotor imagery in the blind.

A previous functional magnetic resonance imaging (fMRI) study in sighted individuals showed deactivations of multisensory vestibular cortex areas in the posterior insula and adjacent temporal sites during locomotor imagery. These vestibular deactivations were suggested to reflect the suppression of vestibular signals during locomotion in order to prevent potentially adverse interactions of these inputs with the optimized automated locomotion pattern. In this fMRI experiment, 10 totally blind subjects and 10 age- and gender-matched sighted controls imagined several locomotor tasks in a first-person perspective (kinesthetic imagery of standing, walking, and running). As opposed to their sighted controls, totally blind individuals activated multisensory vestibular areas in the posterior insula and superior temporal gyrus, with right-sided preponderance during locomotor imagery. These results plausibly suggest that blind subjects rely more on vestibular feedback for locomotor control than do sighted subjects. Thus, this fMRI study provides neuroimaging evidence for distinct cortical processing in the multisensory vestibular system in the blind during locomotor control.