The bilateral central vestibular system: its pathways, functions, and disorders

Abstract

The bilateral anatomical organization of the vestibular system provides three functional advantages: optimal differentiation of head motion and orientation, sensory substitution of a unilateral peripheral failure, and central compensation of a peripheral or central vestibular tone imbalance. The structure is based on bilaterally ascending and descending pathways and at least four crossings: three in the brain stem and one in the cortex. The resulting sensorimotor functions can be subdivided into three major groups: (1) reflexive control of gaze, head, and body in three spatial planes (yaw, pitch, roll) at the brain stem/cerebellar level; (2) perception of self-motion and control of voluntary movement and balance at the cortical/subcortical level; and (3) higher vestibular cognitive functions (e.g., spatial memory and navigation). The bilateral representation of the vestibular system in multiple multisensory cortical areas and the vestibular dominance of the nondominant hemisphere raise the question of how one global percept of motion and orientation in space is formed.

Visual-vestibular processing in the human Sylvian fissure

“…Despite these limitations, our goal in this study was to use a canonical caloric stimulation design, following previous descriptions, to produce optimal vestibular stimulation conditions for PIVC (e.g., Bense et al 2001;Dieterich et al 2003;Fasold et al 2002;Indovina et al 2005;Lobel et al 1998;Stephan et al 2005). In these studies, participants did not perform any task related to their sensations during caloric stimulation and they kept their eyes closed.…”

“…Despite the obvious importance of vestibular signals, the cortical organization of the vestibular system is not yet well established. Unlike other sensory systems, the number of vestibular cortical areas and the information they represent are still under debate (Dieterich and Brandt 2015;Guldin and Grüsser 1998;Kahane et al 2003;Lopez and Blanke 2011;Lopez et al 2012).…”

“…This information is of critical relevance for guiding locomotion and for process- There is accumulating evidence that the potential hub of the cortical vestibular network is located in a region including the posterior part of the Sylvian fissure (also called lateral sulcus), perisylvian cortex, and the posterior insula. At this site, functional imaging studies in humans found activation during vestibular stimulation (Bense et al 2001;Dieterich et al 2003;Eickhoff et al 2006;Fasold et al 2002;Lobel et al 1998) and labeled it the parieto-insular vestibular cortex (PIVC), following terminology in the primate brain (Akbarian et al 1988;Chen et al 2010;Grüsser et al 1990; Shinder and Newlands 2014).…”

“…For the definition of area PIVC, in addition to previous descriptions (e.g., Deutschländer et al 2002;Dieterich et al 2003;Eickhoff et al 2006;Lopez and Blanke 2011;Lopez et al 2012;zu Eulenburg et al 2012), results of a random-effects group analysis of the vestibular localizer were used (Fig. 3C).…”

“…This information is of critical relevance for guiding locomotion and for process- There is accumulating evidence that the potential hub of the cortical vestibular network is located in a region including the posterior part of the Sylvian fissure (also called lateral sulcus), perisylvian cortex, and the posterior insula. At this site, functional imaging studies in humans found activation during vestibular stimulation (Bense et al 2001;Dieterich et al 2003;Eickhoff et al 2006;Fasold et al 2002;Lobel et al 1998) and labeled it the parieto-insular vestibular cortex (PIVC), following terminology in the primate brain (Akbarian et al 1988;Chen et al 2010;Grüsser et al 1990; Shinder and Newlands 2014).However, the vestibular network in the posterior Sylvian fissure is likely more complex and might include at least one additional area, named posterior insular cortex (PIC), that responds to vestibular stimuli as well as to visual object motion and potentially serves as a site of multisensory integration .The anatomical and functional relationship between PIC and PIVC is still unclear, because both areas have not yet been investigated in the same participant. Therefore, in this study we aimed to define and compare the regions known as PIVC and PIC directly in the same participants.…”