Gaze stabilization in chronic vestibular-loss and in XXXX : Interactions of feedforward and sensory feedback mechanisms.

@entity1 @entity135 @entity910 @entity1017 @entity6447 @entity717
During gaze shifts, @entity1 can use visual, vestibular, and proprioceptive feedback, as well as feedforward mechanisms, for stabilization against active and passive @entity910 . The contributions of feedforward and sensory feedback control, and the role of the cerebellum, are still under debate. To quantify these contributions, we increased the head moment of inertia in three groups (ten healthy, five chronic vestibular-loss and nine @entity6447 @entity1 ) while they performed large gaze shifts to flashed targets in darkness. This induces undesired @entity135 . Consequently, both active (desired) and passive (undesired) @entity910 had to be compensated for to stabilize gaze. All groups compensated for active and passive @entity910 , vestibular-loss @entity1 less than the other groups (P < 0.001, @entity1017 : vestibular-loss 0.23    0.09/0.43    0.12, healthy 0.80    0.17/0.83    0.15, @entity6447 .17/0.77    0.30, mean    SD). The compensation gain ratio against @entity717 was smaller than one in vestibular-loss @entity1 (0.54    0.10, P=0.001). Healthy and @entity6447 @entity1 did not differ in active and passive compensation. In summary, vestibular-loss @entity1 can better stabilize gaze against active than against passive @entity910 . Therefore, feedforward mechanisms substantially contribute to gaze stabilization. Proprioception alone is not sufficient (gain 0.2). Stabilization against active and passive @entity910 was not impaired in our @entity6447 @entity1 .
