Multisensory Integration: Mathematical Solution of Inherent Sensory Ambiguities

The brain integrates information from multiple sensory modalities to generate appropriate motor output and create perceptual experiences of the environment. Multisensory integration is evident at the single-neuron level in the cerebral cortex as well as the subcortical areas or brainstem nuclei. In the last two decades, the cerebellum has received increasing interest as an essential structure for multisensory integration. Studies have shown that the cerebellum integrates vestibular signals with signals from other sensory modalities to generate predictions of our inertial motion, orientation, postural control, and gaze stabilization. Here, we review recent literature on the cerebellar role in the integration of vestibular, visual, and proprioceptive signals for spatial navigation. First, we present evidence that the cerebellum contributes to solving the ambiguity found in vestibular afferent information. Theoretical and behavioral evidence indicates that this vestibular sensory ambiguity is resolved by the central nervous system using a combination of otolith signal and rotational cues from the semicircular canals. Second, in the light of recent findings, we describe the role of the cerebellum in integrating vestibular and visual information. Third, we describe how the cerebellum may integrate vestibular and proprioceptive cues.