Pallid mutant mice with no otoconia in their gravity receptors were behaviorally tested and their vestibular nuclei measured to determine if this developmental sensory deprivation had any detrimental effect on central vestibular structure and function. This absence of otoconia was correlated with disorientation in water and absence of air righting reflexes. The inferior and superior vestibular nuclei were smaller than normal, but neurons within regions that receive direct gravity receptor input were smaller only unilaterally in medial vestibular nucleus. It was tentatively concluded that the sensory deprivation resulting from reduced gravity receptor input was responsible for the behavioral and central morphological abnormalities.