Over the past few decades, various cortical regions in primates have been labeled as vestibular: area 2v, area 3, area 7, superior temporal gyrus and parieto-insular vestibular cortex (PIVC). These areas have reciprocal connections with each other and form an "inner circuit." The PIVC physiologically responds well to vestibular stimulation as well as visual and somatosensory inputs. It also morphologically receives projections from all other vestibular cortical regions. Thus these findings suggest that PIVC integrates multisensory information from different cortical areas. The PIVC may play a major role in the cortical vestibular system.
We recorded neuromagnetic responses to visually-induced linear forward acceleration in humans using a 122-channel whole cortex neuromagnetometer. In the study, visual stimulation without vestibular stimulation induced activation in the PIVC in humans. Hence, it is suggested that the vestibular cortex not only receives vestibulr inputs from peripheral vestibular apparatus, but also produces vestibular sensation using other multi-model inputs.
The monkey, cat and rat have homologous vestibular cortical system over species, which projects corticofugally onto the vestibular nuclei. These projections may play a role in an antagonistic coordination of involuntary oculomotor and skeletomotor movements during head movements or locomotion.
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