Visual-vestibular interactions

The human brain uses information from various sensory systems to gauge orientation of the body with respect to the external environment. Our perception of space is based on the image of the external world as registered by various senses and continuously updated and stabilized through sensory feedback from motor activities. In this process, multisensory integration can resolve ambiguities associated with the inherent “noise” from discrete sensory modalities. Accordingly, convergence of visual and vestibular inputs plays a significant role in our perceptions of spatial orientation and motion, which are essential for motor planning and interaction with the external environment. Once movements are generated, the visual-vestibular integration is imperative for optimizing vision and stabilizing the line of sight during movements of the head (i.e., gaze stabilization). Such visual-vestibular interactions are vital for maintaining a coherent perception of spatial orientation during static or dynamic changes in positions of the head and body. In this chapter, we will discuss the basic principles of visual-vestibular interaction within the frameworks of heading (e.g., walking or running) and head tilt with relation to gravity (e.g., a lateral tilt of the head on body). We first describe the fundamental aspects of multisensory integration in these processes along with the underlying physiological and anatomical correlates. We then discuss experimental hypotheses and research findings related to visual-vestibular interaction and outline their clinical applications in human diseases.