Anticompensatory fast phases (AFPs) to vestibular step stimulation in the vertical and horizontal planes and spontaneous saccades were recorded in cats in the upright position and 90° side-down positions. With increasing stimulus velocity, the AFPs of the horizontal vestibulo-ocular reflex (HVOR) increased in cumulative amplitude. AFPs of the vertical VOR (VVOR) were smaller compared to HVOR and showed only a slight increase in cumulative amplitude with increasing stimulus velocity. In contrast, AFP amplitude calculated for VVOR evoked in side-down position increased with increasing velocity as observed for HVOR. AFP direction was aligned with the horizon regardless of both the stimulus plane and animal position. Also the direction of spontaneous saccades tended to be aligned with the horizon. The distribution area of the final points of AFPs was elliptic with the major axis oriented in the horizontal plane. Its projection onto the retina corresponded to the high receptor density area. The ellipse orientation did not change with respect to space up to 30° of head inclination. Beyond this limit the major axis of the ellipse tended to be progressively less aligned with the horizon. The same trend was observed for spontaneous saccades.
Otolithic control of anticompensatory fast phases (AFPs) in cats
SANTARELLI, ROSAMARIA
1994
Abstract
Anticompensatory fast phases (AFPs) to vestibular step stimulation in the vertical and horizontal planes and spontaneous saccades were recorded in cats in the upright position and 90° side-down positions. With increasing stimulus velocity, the AFPs of the horizontal vestibulo-ocular reflex (HVOR) increased in cumulative amplitude. AFPs of the vertical VOR (VVOR) were smaller compared to HVOR and showed only a slight increase in cumulative amplitude with increasing stimulus velocity. In contrast, AFP amplitude calculated for VVOR evoked in side-down position increased with increasing velocity as observed for HVOR. AFP direction was aligned with the horizon regardless of both the stimulus plane and animal position. Also the direction of spontaneous saccades tended to be aligned with the horizon. The distribution area of the final points of AFPs was elliptic with the major axis oriented in the horizontal plane. Its projection onto the retina corresponded to the high receptor density area. The ellipse orientation did not change with respect to space up to 30° of head inclination. Beyond this limit the major axis of the ellipse tended to be progressively less aligned with the horizon. The same trend was observed for spontaneous saccades.Pubblicazioni consigliate
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