Otolith Deprivation Induces Optokinetic Compensation

• Published in: Journal of neurophysiology Vol. 94; no. 5; pp. 3487 - 3496
• Main Authors: Andreescu, Corina E, De Ruiter, Martijn M, De Zeeuw, Chris I, De Jeu, Marcel T. G
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-11-2005
• Subjects: Acceleration; Adaptation, Physiological; Animals; Computer Simulation; Eye Movements; Head Movements; Mice; Mice, Inbred C57BL; Models, Neurological; Motion Perception; Nystagmus, Pathologic - physiopathology; Otolithic Membrane - physiopathology; Photic Stimulation - methods; Physical Stimulation - methods; Reflex, Vestibulo-Ocular; Semicircular Canals - physiopathology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00147.2005

Department of Neuroscience, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
Submitted 11 February 2005;
accepted in final form 27 July 2005
According to the multisensory integration theory vestibular, optokinetic and proprioceptive inputs act in concert to maintain a stable retinal image of the visual world. Yet, it remains elusive to what extent the otolith organs contribute to this process and whether a specific loss of otolith input is compensated for. Here we investigated the compensatory eye movements in tilted mice, which lack otoconia because of a mutation in otopetrin 1. Tilted mice showed very small displacements of the eyes in the orbit during static roll paradigms, suggesting the absence of functional otolith organs. Independent of head position with respect to gravity, the gain and phase lead of angular vestibuloocular reflex of tilted mice were decreased and increased, respectively (frequencies 0.2 to 1 Hz and peak accelerations 8 to 197°/s 2 , respectively). Furthermore, lack of otolith input increases the dependency of the vestibular system on stimulus frequency. In contrast, the gain of optokinetic reflex in tilted mice was significantly higher in the low-frequency range than in control mice, regardless of the position of the mice in space or the plane of the eye movements. To explain these results, a simple model was used in which a multisensory integration unit was embedded. With this model, we were able to simulate all the behaviors observed. Thus our data and the model support the presence of the multisensory integration system and revealed a compensatory enhanced optokinetic reflex in tilted mice, indicating an adaptive synergism in the processing of otolith and visually driven signals.
Address for reprint requests and other correspondence: M. de Jeu, Department of Neuroscience, Erasmus University Medical Center Rotterdam, Dr. Molewaterplein 50, 3000 DR, Rotterdam, The Netherlands (E-mail: m.dejeu{at}erasmusmc.nl )