Animal studies linking the vestibular system and memory: Aotearoa/New Zealand's contribution.

Animal studies of the mammalian vestibular system began at the University of Otago in 1987. From approximately 2000, these studies focused on the effects of vestibular lesions and stimulation, on spatial memory and the hippocampus. Our research has shown that, as well as the deficits in the vestibulo-ocular and vestibulo-spinal reflexes that occur following vestibular dysfunction, vestibular loss may also cause cognitive disorders, especially spatial memory deficits, some of which are related to the contribution of ascending vestibular pathways to the function of the limbic system and neocortex in regulating spatial orientation. In addition to behavioural demonstrations of spatial memory deficits, we have demonstrated that vestibular loss is associated with a variety of dysfunctional changes in the hippocampus, which may be responsible for the spatial memory deficits. These memory deficits are unlikely to be due to hearing loss, problems with motor control, oscillopsia or anxiety and depression. These animal studies have raised awareness of cognitive deficits associated with vestibular disorders and contributed to their recognition and treatment.