PT - JOURNAL ARTICLE AU - Andrea M. Green AU - Dora E. Angelaki TI - Resolution of Sensory Ambiguities for Gaze Stabilization Requires a Second Neural Integrator AID - 10.1523/JNEUROSCI.23-28-09265.2003 DP - 2003 Oct 15 TA - The Journal of Neuroscience PG - 9265--9275 VI - 23 IP - 28 4099 - http://www.jneurosci.org/content/23/28/9265.short 4100 - http://www.jneurosci.org/content/23/28/9265.full SO - J. Neurosci.2003 Oct 15; 23 AB - The ability to simultaneously move in the world and maintain stable visual perception depends critically on the contribution of vestibulo-ocular reflexes (VORs) to gaze stabilization. It is traditionally believed that semicircular canal signals drive compensatory responses to rotational head disturbances (rotational VOR), whereas otolith signals compensate for translational movements [translational VOR (TVOR)]. However, a sensory ambiguity exists because otolith afferents are activated similarly during head translations and reorientations relative to gravity (i.e., tilts). Extra-otolith cues are, therefore, necessary to ensure that dynamic head tilts do not elicit a TVOR. To investigate how extra-otolith signals contribute, we characterized the temporal and viewing distance-dependent properties of a TVOR elicited in the absence of a lateral acceleration stimulus to the otoliths during combined translational/rotational motion. We show that, in addition to otolith signals, angular head position signals derived by integrating sensory canal information drive the TVOR. A physiological basis for these results is proposed in a model with two distinct integration steps. Upstream of the well known oculomotor velocity-to-position neural integrator, the model incorporates a separate integration element that could represent the “velocity storage integrator,” whose functional role in the oculomotor system has so far remained controversial. We propose that a key functional purpose of the velocity storage network is to temporally integrate semicircular canal signals, so that they may be used to extract translation information from ambiguous otolith afferent signals in the natural and functionally relevant bandwidth of head movements.