During nystagmus induced by the angular vestibuloocular reflex (aVOR), the axis of eye velocity tends to align with the direction of gravito-inertial acceleration (GIA), a process we term "spatial orientation of the aVOR." We studied spatial orientation of the aVOR in rhesus and cynomolgus monkeys before and after midline section of the rostral medulla abolished all oculomotor functions related...

The visual system incorporates a phylogenetically ancient subsystem that responds to overall movement of the retinal image. Its signals induce animals to turn their eyes, heads or bodies to correct the perturbing motion and keep the image as stable as possible. Human optokinetic nystagmus (OKN) is an example: if the eyes are presented with largefield movement, such as the view from the window o...

Background/aims: Few studies have investigated normal response characteristics of torsional optokinetic nystagmus (tOKN). The authors have investigated the effect of stimulus velocity and central/peripheral stimulation on tOKN. Methods: Torsional OKN was elicited using a sinusoidal grating rotating at velocities of 3 /̊s to 1000 /̊s in clockwise and anticlockwise directions. To investigate the ef...

The decision whether a nystagmus is congenital or acquired may be difficult and is of importance in patients presenting with neurological complaints. In this article, established diagnostic criteria are critically reviewed with particular emphasis on types of nystagmus waveform and their relationship to pursuit and optokinetic responses. Attention is drawn to certain acquired nystagmus which ma...

Monkeys with 1 eyelid sutured within 2 weeks of birth for 7 or 14 d (short-term monocular deprivation, n = 5) or for 18-26 months (long-term monocular deprivation, n = 5) were tested for visual and oculomotor function at approximately 2 years of age. Long-term monocularly deprived animals were behaviorally blind when visual inputs were restricted to the deprived eye. There was no sparing of the...

Prolonged binocular optokinetic stimulation (OKS) in the rabbit induces a high-velocity negative optokinetic afternystagmus (OKAN II) that persists for several hours. We have taken advantage of this uniform nystagmus to study how changes in static head orientation in the pitch plane might influence the orientation of the nystagmus. After horizontal OKS, the rotation axis of the OKAN II remained...

Optokinetic nystagmus is the term applied to the nystagmus evoked by a succession of moving objects passing before the eyes (Brain, 1962). It has proved useful as a diagnostic tool in the examination of patients with neurological disease (Cogan, 1956; Huber, 1961; Smith, 1963; Walsh, 1957). Methods of inducing and suppressing optokinetic nystagmus have also been used as the basis for objective ...